| Title |
Investigators | Department | Objectives | Approach Keywords | Progress Reports | Impact Statements | Publications | |
Project * COL00644 | |
| Title | Genomics of Economically Important Traits in Wheat and Barley |
| Investigator(s) | Lapitan, NL; |
| Department | Soil and Crop Sciences |
| Objectives | The long-term goal of this project is to identify genes and pathways involved in complex and agronomically important traits in wheat and barley using genomics approaches. Specific objectives are to: 1.) Conduct high resolution mapping for Russian wheat aphid resistance (RWA) gene, Dn7. 2.) Positionally clone the Dn7 gene. 3.) Identify elicitor(s) from the Russian wheat aphid. 4.) Identify wheat genes involved in defense response to RWA infestation. 5.) Identify genetic determinants of malting quality in barley. |
| Approach | The current Dn7 map is flanked by Xhor2 and Xscb241 with a genetic distance of 2.1 cM. This region will first be saturated with markers until a marker that co-segregates with Dn7 is identified. When this is achieved, 1RS BAC clones containing markers linked to Dn7 will be identified. Low copy sequences from the BACs will be mapped in a high resolution mapping population consisting of 2000 F2 individuals. The closest markers to Dn7 will be used for the next round of screening the 1RS BAC library, followed by mapping, until BAC clones containing markers flanking Dn7 overlap. BAC clones in the contig will be sequenced and candidate genes will be identified based on presence of open reading frames, and predicted function. Lastly, candidate genes will be silenced in Gamtoos-R using virus-induced gene silencing (VIGS). Silenced genes that result in susceptible phenotypes in Gamtoos-R following RWA infestation will be identified as a candidate for the Dn7 locus. The protein(s) consisting the Russian wheat aphid elicitor will be identified by extracting proteins from salivary glands, and separating protein fractions by gel filtration. Different fractions will be assayed for ability to produce susceptible symptoms in susceptible wheat plants following injection of protein fractions. The identity of proteins will be determined by mass spectrometry. Wheat genes involved in defense response to Russian wheat aphid infestation will be identified by means of transcript profiling studies using wheat gene chip microarrays. Transcript profiling studies in barley using the Barley 1 gene chip array will be conducted to identify candidate genes for malting quality phenotypes. Differentially expressed genes in comparisons among four malting barley cultivars and four malting stages of Morex vs. dry seed will be correlated with malting quality phenotypes. |
| Keywords | Wheat, Barley, Russian wheat aphid, interaction, defense mechanism, elicitor, biotype, malting quality, microarrays, mapping, positional cloning |
| Progress Reports | |
| 1993 | A molecular map of barley containing 295 RFLP, isozyme, and morphological marker was constructed. Experiments were conducted to add more RFLP markers to the map. This densely populated map will be used by breeders and geneticists to identify economically important traits such as disease and insect resistance, and yield. Comparative RFLP mapping between barley and a diploid progenitor of wheat, Triticum tauschii, was conducted. The results showed that more than 95% of DNA sequences tested were shared between barley and T. tauschii. The order of DNA markers on chromosomes of the two species were very similar. However, there were a few differences in marker order observed between the two species that may have been brought about by duplications and deletions of DNA sequences during evolution. The results indicate that single copy RFLP markers in barley may be used for mapping in T. tauschii and wheat, and vice versa. Results also indicate that genes for agronomically important traits may be found in the same chromosomal positions in barley and wheat. Wheat is a hexaploid and is more difficult to analyze genetically and molecularly. These results indicate that barley may be used to identify and clone genes controlling agronomically important traits in wheat. |
| 1994 | A comparative RFLP mapping study between barley and Triticum tauschii was completed. The order of RFLP markers on the chromosomes of the two species were very similar, indicating that RFLP markers can be used interchangeably between barley and T. tauschii (and wheat). A barley map which incorporates markers from three previously published barley maps was constructed to enable the alignment of the different barley maps. By aligning the maps, the new map provides researchers with a larger number of markers for each specific chromosome region. The map also includes markers from rice. A comparison of the barley and rice maps showed conserved linkage groups between the two species. This indicates that rice markers can be used for barley and wheat mapping, and vice versa. A genomic library of barley in a bacterial artificial chromosome (BAC) vector is being constructed for use in physical mapping and map-based cloning . Twenty-eight Solanum species and accessions were surveyed for bacterial ring rot (BRR) reaction and RFLPs in a study to genetically map the genes for immunity to BRR. An accession of S. acaule and of S. phureja were found to be immune to BRR. S. acaule was crossed with a susceptible diploid S. infundibuliforme accession. The F1 progeny segregated 3:1 for non- immune:immune. RFLPs which are segregating in the S. acaule parent will be identified and correlated with immunity. DNA markers linked to the immunity genes can be used as visual tags for transferring the immunity genes to suscept. |
| 1995 | This project is composed of three subprograms. All had substantial progress during this period . DNA markers linked to two genes for resistance to Russian wheat aphid (RWA) were identified. The genes Dn2 and Dn4 from PI262660 and PI372129 were found to be linked to RFLP markers KSUA1 and MWG837, respectively. DNA markers tightly linked to the genes will be used in the wheat breeding program to facilitate selection of resistant plants and to combine multiple resistance genes into a single genotype. Resistance to RWA in the Russian triticale lines PI386148 and PI386150 was localized to chromosome 4Rm of Secale montanum by genetic and cytogenetic analyses and a manuscript describing this work is in press. This finding and the availability of rye-specific DNA probes should facilitate the transfer of RWA resistance from the triticale lines into wheat. The genetic control of immunity to bacterial ring rot (BRR) in Solanum acaule was determined. Two dominant genes at two different loci were shown to be required for immunity. This finding will be important in developing strategies to transfer bacterial ring rot immunity into potato cultivars. A protocol for physical mapping of single copy sequences by fluorescence in situ hybridization (FISH) was developed in barley and is described in a manuscript in preparation. The FISH protocol enables direct localization of genes to chromosomes and will aid in the isolation of economically important genes whose products are unknown. |
| 1996 | This project is composed of several subprograms and substantial progress was made in all subprograms during this period. Two genes for resistance to Russian wheat aphid, Dn2 and Dn4, were mapped using RFLP markers. The AFLP technique was tested for its usefulness in genetic mapping in wheat and the results showed that this technique is able to uncover large numbers of polymorphisms in wheat. Quantitative trait loci controlling fusarium head blight in barley were mapped. A fluorescence in situ hybridization (FISH) technique for physical mapping of genes in barley was developed and is described in a paper in press. A USDA NRI Competitive Grant with D. Knudson as Co-P.I. was funded to investigate gene organization in barley using FISH. A hypersensitive response-mediated resistance to the pathogen causing bacterial ring rot in potato was discovered in leaves of Solanum acaule. These studies are important because they focus on the application of molecular techniques to improve crops that are economically important in Colorado and in the U.S. These results will facilitate breeding of resistance to significant disease and insect problems in wheat, barley, and potato by providing DNA markers that can serve as visual tags for the genes in breeding programs. These studies also expand our knowledge base of genome organization and will lay the groundwork for cloning of important genes from wheat, barley, and potato. |
| 1997 | This project focuses on the application of molecular techniques in wheat and barley improvement.This project has three subprograms. Two subprograms involve development of DNA markers for breeding resistance to Russian wheat aphid in wheat and resistance to Fusarium head blight in barley. The third subprogram involves the study of gene organization in barley by fluorescence in situ hybridization (FISH). Significant progress was made in all three subprograms.The Russian wheat aphid (RWA) is the most serious insect pest of wheat in the United States at present. To expedite breeding of resistant cultivars, DNA markers linked to two Russian wheat aphid (RWA) resistance genes (Dn2 and DN4) were developed. The chromosome location of Dn2 and Dn4 were determined. The use of DNA markers for combining Dn2 and Dn4 genes into a single cultivar was evaluated. The results indicate that the DNA markers found will not be useful for pyramiding Dn2 and Dn4 and that markers more tightly linked to these genes are required. Fusarium head blight or scab is the most serious disease threatening barley production in the midwest. Five QTL for scab resistance were identified. Two QTL together explained about 30% of low scab infection and 32% of low vomitoxin (DON) levels. The study on gene organization in barley will provide information on the distribution of recombination frequencies across the genome of barley and it will lay the groundwork for positional cloning in species with large genomes by identifying the regions of chromosomes where genes are located, and by showing whether genes occupy specific domains in barley chromosomes. The results also will provide the basis for the development of a positional cloning strategy that is appropriate for this species. During the first year of this project, we have successfully identified probes that allow unambiguous identification and orientation of each of the seven barley chromosomes. These probes will enable systematic physical mapping of known gene clones and cDNAs on barley chromosomes by FISH. This project has significant economic, environmental, and scientific impact. It is an excellent demonstration of the application of molecular markers to assist selection of important traits in breeding. It is expanding the knowledge base of the genetics of resistance to Russian wheat aphid in wheat and the genetics of resistance to fusarium head blight in barley. It is contributing to the expansion of technical capabilities in genetic and physical mapping in wheat and barley by the development of new techniques such as the AFLP technique and FISH. It is contributing knowledge on the genome organization of wheat and barley. The use of genetic resistance to control the RWA and fusarium head blight protects the environment from pesticides and chemicals used to control these problems. |
| 1998 | This project focuses on the application of molecular techniques in wheat and barley improvement.This project has three subprograms: 1) development of DNA markers for resistance genes to Russian wheat aphid (RWA) in wheat; 2) QTL mapping of resistance genes to Fusarium head blight (FHB) in barley; and 3) study of gene organization in barley by fluorescence in situ hybridization (FISH). Progress was made in all three subprograms. The RWA is the most significant pest problem in wheat in the United States.The use of resistant cultivars is an effective means to control the RWA. DNA markers can facilitate breeding of resistant cultivars by marker assisted-selection. Last year, we reported the identification of RFLP markers linked to two RWA resistance genes, Dn2 and Dn4. Because the closest markers were still about 10 cM away from each gene, AFLP and microsatellite markers were screened to identify DNA markers that are more tightly linked to the genes. Microsatellite marker WMS 437-1 is 2.3 cM away from Dn2, and an AFLP marker (E-ACA/M-CTG) is 7.9 cM away from Dn4. Evaluation of these new markers for their utility in pyramiding Dn2 and Dn4 into a single genotype is underway. FHB or scab is the most serious disease threatening barley production in the midwest. QTL mapping of FHB resistance in the six-rowed cultivar Chevron revealed 9 QTLs for lower FHB severity and 9 QTLs for lower levels of the vomitoxin DON. QTLs associated with heading date and height were also mapped. The two QTLs that contributed the largest effects to lower FHB severity and DON were also associated with late heading or tallness, both of which are traits found in Chevron. These results indicate that these QTLs with major effects on FHB severity and DON may not contain resistance genes, but rather, these appear to be effects of escape from infection. The long term goal of these two projects is to clone and characterize resistance genes.The large genome sizes of barley and wheat (5000 Mbp for barley; 15,000 Mbp for wheat) make the application of positional cloning in these crops extremely difficult and impractical. Hence, we are investigating the gene organization in barley to determine whether barley genes are located in specific domains of the genome. Three probes that allow unambiguous identification and orientation of each of the seven barley chromosomes were identified.An ultrasensitive FISH technique was developed for barley and it was used to determine the physical location on the chromosome of known gene clones and cDNAs that had been previously mapped by genetic segregation. These projects have significant economic, environmental, and scientific impact. The use of DNA markers linked to RWA resistance genes for selection can shorten the development time of plants containing two or more resistance genes by at least half of that required using conventional screening methods. The results on QTL mapping of FHB resistance genes provide breeders with information on regions to select for and avoid. The knowledge gained from the study of gene organization in barley can be used to develop cloning strategies that are appropriate for barley and its relative, wheat. |
| 1999 | This project focuses on the application of molecular techniques in wheat and barley improvement.This project has three subprograms: 1) development of DNA markers for resistance genes to Russian wheat aphid (RWA) in wheat; 2) QTL mapping of resistance genes to Fusarium head blight in barley; and 3) study of gene organization in barley by fluorescence in situ hybridization (FISH). The RWA is one of the most significant pest problems in wheat in the United States.The use of resistant cultivars is an effective means to control the RWA. DNA markers can facilitate breeding of resistant cultivars by marker-assisted-selection. DNA markers for two genes, Dn2 and Dn4, were reported. The marker WMS437, which is linked to Dn2, was proven to be effective for distinguishing plants containing Dn2 from susceptible wheat plants or resistant plants containing genes other than Dn2. This marker would therefore be useful for marker-assisted-selection and pyramiding. Another gene for RWA resistance, Dn7, was genetically mapped. Dn7 originated from rye and was transferred to wheat via a 1RS/1BL chromosome translocation by Dr. Frans Marais (South Africa). Six DNA markers were linked to Dn7, and the nearest marker is only 3.9 cM from the gene. The Dn7 gene confers a level of resistance that is much higher than that conferred by the Dn4 gene, which is contained in the wheat cultivar Halt and other resistant cultivars recently released by Colorado State University. For example, plants containing Dn7 contain at least 10-fold less number of aphids and are more vigorous compared to plants containing Dn4. The second project was completed this year and a paper was submitted for publication. The third project aims to answer the question "how are barley genes organized in the genome?" An ultrasensitive FISH technique was developed for barley and was used to determine the physical location on the chromosome of known gene clones and cDNAs that had been previously mapped by genetic segregation. The FISH physical map shows that most barley genes are located near the ends of chromosomes, which was not expected based on the genetic map information. This finding indicates that map-based cloning of agriculturally important genes in barley and wheat is feasible, despite the large genome sizes of these species (5000 Mbp for barley; 15,000 Mbp for wheat), and supports recent work that has been done in other laboratories. |
| 2000 | The long-term goal of this project is to make cloning of economically important genes in wheat feasible and routine. We are currently focusing on mapping and cloning of genes for resistance to Russian wheat aphid (RWA), which is the most important pest problem in wheat production in Colorado. Significant progress was made toward accomplishment of this objective. A newly identified resistance gene for RWA, Dn7, was genetically mapped using RFLP markers. In a collaboration with Dr. Dennis Knudson, the DNA sequences of ~ 1000 cDNA clones containing sequences expressed during RWA infestation in a line containing Dn7, were determined. Eighty-five percent of the cDNAs were known in the existing databases and 15% represented undescribed, new wheat cDNAs. Fifteen cDNAs were identified as known disease resistance genes. The RWA resistance gene Dn4 was previously mapped genetically by us. We determined the physical distance (no. of DNA base pairs) between the DNA markers flanking Dn4 using fluorescence in situ hybridization. This information is important for map-based cloning of the gene. The two markers flanking Dn4 are less than 1 megabase apart and could be as close as 1 kilobase. This finding was a breakthrough. It opens up the possibility of cloning the Dn4 genes and other genes in wheat, despite its large genome size and low level of genetic polymorphism. It demonstrated that even though the genetic distance between markers may be large, the physical distance may be small and therefore wheat genes are amenable to map-based cloning. |
| 2001 | The long-term goals of this project are to provide DNA markers for marker assisted-selection of agronomic traits, and to make cloning of genes feasible and practical in wheat and barley. Our current focus is to map genes for Russian wheat aphid (RWA) resistance in wheat and clone candidate resistance genes. Significant progress was achieved toward this goal. CDNA libraries were made from a resistant wheat genotype (94M370) from both aphid-infested and non-infested leaf tissues. Subtractive hybridization was performed between the cDNA from infested and non-infested material to identify genes that were differentially expressed during aphid feeding. The DNA sequences of 45 positive clones were determined and analyzed. Approximately 50% of the clones were plastid genes. The other 50% represent clones that were previously associated with defense-response mechanisms in plants, retrotransposons, and genes associated with human tumors. These results provide insights on the molecular mechanism of resistance to the RWA and may lead to the cloning of genes that are useful for genetically engineering resistant genotypes. Great strides were achieved toward efforts to clone a RWA resistance gene by map-based cloning. One BAC clone was identified to contain the two DNA markers flanking the Dn4 gene. If the genetic map is confirmed, this means we have already cloned the Dn4 gene. Seventy-thousand wheat ESTs were produced in an NSF-funded project by a collaborator in Albany . We have mapped 170 ESTs consisting of 324 loci on wheat deletion lines. These resources will advance the capability of wheat researchers to identify genes for agronomically important traits. |
| 2002 | The overall goal of my research program is to use existing genetic variation to improve economically important traits in wheat and barley. There are four ongoing research projects in my lab: 1) Mapping and cloning of genes for resistance to the Russian wheat aphid; 2) Use of markers for marker-assisted selection in wheat breeding; 3) Mapping of expressed sequenced tags (ESTs) in wheat; and 4) Identification of allelic variants for malting quality in barley. Significant progress was made in all four projects. Because of the large genome size of wheat, complete sequencing has not been feasible in the past. Project 3 was conducted as a way to identify the function of all the genes in the wheat genome. Expressed portions of the wheat genome were cloned, sequenced, and mapped by ten labs (including my lab) to wheat chromosomes. As of December 31, 2002, 11173 EST loci were mapped to wheat chromosomes. Of these, 1830 loci were mapped at CSU. These ESTs are available to researchers world-wide through the internet and provide a valuable resource to enable the identification of genes for economically important traits in wheat. The results also contribute to our understanding of organization and evolution of genes in wheat and related species. In the past year, new markers for marker-assisted selection of genes for resistance to the Russian wheat aphid (RWA) were identified. These markers form part of a USDA-IFAFS project to apply markers in wheat breeding . Although molecular markers have been developed for numerous traits in wheat, most of these have not been tested for their utility in breeding. This is the first project that takes a concerted effort to test markers in wheat breeding programs across the U.S. The CSU component (with Dr. Haley as collaborator) involves development of cultivars for Colorado that contain a combination of genes for resistance to the RWA, wheat streak mosaic virus, barley yellow dwarf virus, and high grain protein content. Twenty-five cultivars are expected to be developed from this project using marker-assisted-selection. Six papers reporting findings from the results of these projects have been submitted to refereed journals. One has been accepted, and the others are in review. |
| 2003 | The overall goal of this research program is to use existing genetic variation to improve economically important traits in wheat and barley. One of our accomplishments was to map 907 expressed wheat genes (expressed sequence tags or ESTs) in the chromosomes of wheat. The data are publicly available and provide a valuable resource in advancing wheat research. These ESTs provide candidate genes for economically important traits in wheat when the only information for such a trait is its genetic map. These results have enabled detailed studies on the organization of wheat genes and provide a foundation for subsequent studies to sequence the wheat genome. A second accomplishment is the development of PCR-based DNA markers tightly linked to a Russian wheat aphid resistance gene, Dn7. The importance of this result is highlighted by the appearance of a new aphid biotype in Colorado and other Midwestern states in Spring 2003. All known resistance genes, with the exception of Dn7, were susceptible to this new biotype. The PCR markers developed in this project will expedite the transfer of Dn7 to susceptible wheat cultivars in Colorado and other states. DNA markers for other traits, including wheat streak mosaic virus resistance, and high grain protein, were applied in the wheat breeding program. |
| 2004 | The overall goal of my research program is to use existing genetic variation to improve economically important traits in wheat and barley. Significant progress was made in developing new tools to improve wheat resistance to the Russian wheat aphid (RWA). The RWA is a significant economic problem for wheat and barley growers in the U.S. and most parts of the world. In Colorado alone, average annual losses are estimated at $11 million. The most effective means to control the damage caused by this pest is through the use of resistant cultivars. Within the last two years, however, at least five new biotypes have appeared in the U.S. and overcome resistance genes bred into wheat cultivars. Furthermore, the biotypes cannot be distinguished from each other morphologically and this information is important for breeding new cultivars. We tested RAPD markers on the five biotypes and found a relatively high level of polymorphism among them. DNA fingerprinting kits are being developed to facilitate the identification of biotypes in the field. This will allow the study of biotype alternation over time in the same locations and will provide information necessary for biotype forecasting. We developed an assay that will allow us to identify the chemical components of the RWA toxin. When we injected extracts containing ground RWA, we were able to simulate the leaf-rolling symptom observed in infested susceptible plants. RWA fractions containing total protein or metabolites were isolated and injected into different wheat genotypes. Results show that the protein fraction induces leaf-rolling symptoms in susceptible, but not in resistant plants. The results suggest that the metabolite fraction may also contain components that are important in the virulence of RWA. Improved PCR-based markers flanking the Dn7 wheat resistance gene were developed, These markers are useful for marker-assisted-selection of Dn7 and are currently being used in a related project to develop a germplasm containing the Dn7 gene without the rye secalin gene that is linked to it. |
| 2005 | The Russian wheat aphid (RWA) (Diuraphis noxia) (Mordvilko) (Homoptera: Aphididae), is a major pest of small grains, particularly wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). Between 1986 and 2003, RWA infestations have caused a total economic impact approaching $1 billion, including the use of nearly 20 million pounds of insecticides. Resistant cultivars have provided the most effective means to control the damage caused by the aphid. However, from 2003-2005, at least five new biotypes appeared and were virulent to existing resistant cultivars. Dn7 is a single dominant gene that confers resistance to most of the new biotypes, as well as the original biotype. A saturated map of Dn7 containing 26 molecular markers was made. Nine PCR-based markers were developed which can be used for marker-assisted-selection (MAS) of Dn7. When the two markers flanking the Dn7 gene are used for MAS, the probability of selecting a plant that is homozygous for Dn7 is >96% in the F2 generation. Last year, we reported the development of an in planta assay to identify the chemical components from the RWA responsible for inducing symptoms in wheat. Total extract (containing ground aphid in buffer) or RWA-protein extract injected into wheat seedlings resulted in differential responses between resistant and susceptible genotypes. Resistant plants showed flat leaves while susceptible plants showed leaf rolling. We further investigated biochemical responses in resistant and susceptible genotypes injected with different RWA extracts. Resistant plants injected with total extract or protein extract had significantly higher activities in three defense-related enzymes compared to susceptible genotypes and control plants injected with buffer only. The enzymes included catalase, beta-glucanase, peroxidase, and are known to be involved in plant resistance to pathogens. These results suggest that an elicitor from the aphid is recognized by wheat, and this recognition initiates a cascade of reactions that involve the immediate induction of defense-response genes in resistant plants. Isolation of the aphid elicitor and understanding its mode of action in plants can provide new strategies for controlling the damage caused by the RWA. These results are important in providing a sustainable solution to the damage caused by the RWA. First, molecular markers for resistance genes can expedite the development of cultivars that are resistant to the new biotypes. Second, innovative ways to control the RWA will come from an understanding of the molecular interaction between the RWA and wheat. |
| 2006 | The Russian wheat aphid (RWA), Diuraphis noxia, is a major pest of small grains, particularly wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). Between 1986 and 2003, RWA infestations have caused a total economic impact approaching $1 billion, including the use of nearly 20 million pounds of insecticides. Resistant cultivars have provided the most effective means to control the damage caused by the aphid. However, the appearance of at least five new biotypes that were virulent to existing resistant cultivars between 2003-2006 presents a difficult challenge for breeders. Our long term goal is to develop DNA markers for genes that confer or contribute to wheat resistance to the RWA. Results for three sub-projects are reported here. In the first study, markers were developed for two wheat accessions, STARS2002RWA2414-11 (2414-11) and CI2401, both of which provide resistance to the predominant U.S. biotype (bioytpe 2) and to biotypes 1 and 3. Thirty markers were linked to 2414-11, with 16 markers co-segregating with resistance. An unexpected result from this study was the finding that a rye chromosome arm is present in 2414-11 and is the source of the resistance gene. The single dominant resistance gene in CI2401 was mapped to chromosome 7DS. Three SSR markers (Xbarc126, Xgwm111 and Xgwm121) on 7DS were genetically linked to this gene . The aim of the second study was to identify other wheat genes that are important in defense response to RWA feeding. The Wheat Gene Chip microarray was used to identify genes that were differentially expressed between resistant and susceptible wheat genotypes during RWA infestation. A total of 477 genes were differentially expressed between resistant and susceptible plants 5 hours post-infestation. These include genes involved in biosynthesis of and response to jasmonic acid, salicylic acid, and ethylene. In the third study, we analyzed genetic diversity among eight RWA biotypes to determine the possible source of new biotypes and to assess the feasibility of developing DNA fingerprints to distinguish the biotypes. Analysis of more than 5000 DNA fragments revealed very low polymorphisms (~ 0.12%) among the biotypes. Comparison of DNA sequences for the mitochondrial oxidase gene, mtCOI, among the eight biotypes showed that biotypes 1 to 7 had identical DNA sequences, while biotype 8 showed a nucleotide divergence of 0.2%. The results indicate that it will be difficult to develop DNA fingerprints to distinguish the different biotypes. The results suggest that differences in host specificity may be conferred by a very small number of genes, and the differences among biotypes likely arose from mutation. Our ongoing studies to identify proteins from the RWA that elicit susceptible symptoms in wheat is one way to go after the genes that confer host-specificity in the RWA. |
| Impact | |
| 1999 | The use of DNA markers linked to RWA resistance genes in selection can shorten the breeding time especially of cultivars containing more than one resistance gene. Using DNA markers, the development time of cultivars containing two or more resistance genes is cut by half, which translates to savings of millions of dollars per year for wheat growers. Furthermore, the use of resistant cultivars protects the environment from chemicals used to combat the RWA and supports a sustainable agriculture. |
| 2000 | Wheat is one of the two most important cereal crops in the world (the other is rice). Its large genome size presents difficulties in cloning of important genes in these species. The findings of this study provide different approaches to accessing genes in wheat. Sequencing of cDNAs made from a RWA-infested plant is one approach to identify genes responsible for RWA resistance. Results from genetic and physical mapping provide the basis for cloning by a map-based approach. |
| 2001 | Wheat is one of the most important cereal crops in the world. Its large genome size presents difficulties in cloning of important genes in this species. The strategies and genomics tools developed in this project will enable scientists to clone important genes from wheat and related species. The cloning of a RWA resistance gene from wheat will represent the first insect resistance gene cloned from a plant, and the first agronomically important gene cloned from wheat. |
| 2002 | Wheat is one of the most important crops in the world and the most important in Colorado. This project provides DNA markers to facilitate breeding of wheat cultivars that contain a combination of genes for desired characteristics, such as resistance to pests and diseases, and high grain protein content. Marker-assisted selection (MAS) cuts down the time to produce cultivars containing desired gene combinations. Furthermore, MAS makes it possible to combine genes that are difficult to accomplish using conventional selection methods. For example, the combination of 2 or more RWA resistance genes in the same cultivar since there is currently only one aphid biotype in the U.S. The strategies and genomics tools (such as ESTs) developed in this project will support scientists worldwide in efforts to clone important genes from wheat and barley. |
| 2003 | The generation of ESTs and physical locations in the wheat genome provide a valuable resource for wheat research worldwide. Genes for economically important traits that cannot be cloned using conventional approaches may now be cloned using the sequence information and map locations generated in this study. This study makes significant contributions to the knowledge base of wheat genetics. Practical decisions in research, such as whether to use the rice genome sequence to clone a particular wheat gene, will be supported by the resources and new discoveries generated by this project. Our studies on identification of RWA resistance genes ensure sustainability of wheat crops in the advent of appearance of new biotypes. PCR-based markers for Dn7 and other resistance genes will expedite breeding for wheat cultivars containing two or more resistance genes. |
| 2004 | The ability to identify RWA biotypes using DNA markers will allow plant breeding programs to make informed choices regarding the sources of resistance to utilize gene and gene combination strategies. It will help growers in choosing cultivars. Changes in biotype composition within a loction can be studied using these markers, and this will allow biotype forecasting. PCR-based markers for the Dn7 gene, which provides a high level of resistance to biotypes 1 and 2, will facilitate the development of new resistant wheat germplasm and cultivars. |
| 2005 | The RWA is a significant economic problem for wheat growers in the western U.S., with average annual losses in Colorado estimated at $11 million. These results provide PCR-based markers for Dn7, a gene conferring a high level of resistance to at least four new biotypes of RWA. PCR-markers will facilitate the development of new resistant wheat germplasm and cultivars. Results of in plant assays to determine the chemical components of RWA that elicit the susceptible symptoms in wheat provide the basis for isolation and identification of aphid elicitors. Isolation of aphid elicitors can lead to the development of innovative strategies to control the damage caused by RWA. |
| 2006 | The markers developed for the resistance genes in 2414-11 and CI2401 will be useful for marker-assisted-breeding to expedite the development of new cultivars containing one or more resistance genes to new biotypes of RWA. Before this study, it was not known that resistance in 2414-11 came from a rye chromosome arm (1RS). Since the rye chromosome 1RS also carries the secalin gene which causes sticky dough in the wheat flour, it is generally not a preferred source of genes for wheat breeding in the U.S. The results of this study provide information that will be useful to wheat breeders in deciding whether to use this otherwise excellent source of resistance to many RWA biotypes. Identification of wheat genes that are important in wheat's defense to attack by the RWA may provide new strategies for developing resistance. For example, a combination of favorable alleles other than the resistance locus may provide resistance to a broad spectrum of biotypes. Genetic diversity studies among RWA biotypes indicate the importance of continuing the use of plant differentials to identify biotypes. The results support the need to identify elicitors from the RWA that induce host-specific reactions in wheat. The identification of these RWA elicitors and understanding the mechanism that leads to host susceptibility or resistance may lead to methods of blocking the development of susceptible symptoms. |
| Publications | |
| 1993 |
GILL, B. S. ET AL. 1993. Genetic & physical mapping in Trit. taus. and Trit. aest. In: Progress in genomemapping of wheat and related species. D. Hoisington and A. McNab (eds). Proc . of 3rd public workshop of ITMI, CIMMYT, Mexico. KLEINHOFS, A. ET AL. 1993. A molecular, isozyme, and morphological map of the barley (Hordeum vulgare) genome. Theor. Appl. Genet. 86:705-712. NAMUTH, D.N. 1993. Comparative RFLP mapping of Hordeum vulgare and Triticum tauschii. M.S. Thesis. Colorado State Univ., Fort Collins, CO. 33 p. NAMUTH, D.N., LAPITAN, N.L.V., GILL, K. S. AND GILL, B.S. 1992. Comparative RFLP mapping of Hordeum vulgare and Triticum tauschii. Barley Genetics Newsletter 21:57-60. NKONGOLO, N., QUICK, J. , MUHLMAN, D., AND LAPITAN, N. 1993. An optimized fluorescence in situ hybridization procedure for detecting rye chromosomes in wheat. Genome 36:701-705. RODER, M., LAPITAN, N.L.V., SORRELLS, M.E., AND TANKSLEY, S.D. 1993. Genetic and physical mapping of barley telomeres. Mol. Gen. Genet. 238:294-303. |
| 1994 |
ISHIMARU, C. A. 1994. A survey of Solanum species for DNA polymorphisms and reactions to bacterial ring rot. Plant Genome II Abstracts, p. 45.2nd Int. Conference on the Plant Genome, San Diego, CA. 1994 ISHIMARU, C.A. ET AL 1994. Identification of parents suitable for molecular mapping of immunity and resistance genes in Soanum species. Amer. Pot. J. 71:517-533. 1994 LAPITAN, N. L. V. 1994. Molecular mapping of genes for economically important traits in plants . The Colorado Institute of Research in Biotechnology Newsletter. 7(2): 4-5 LAPITAN, N.L.V., ET AL. 1994. Plant telomeres: macrostructure, genetic mapping,& role in chromosome stability. 4th Int'l Conf. of Plant Molecular Biology Abst., p. 15. The Int'l Society for Plant Molecular Geneticists NAMUTH, D.N., LAPITAN, N.L.V., GILL, K. S., AND GILL, B. S. 1994. Comparative RFLP mapping of Hordeum vulgare and Triticum tauschii. Plant Genome II Abstracts, p. 45.2nd Int. Conference on the Plant Genome, San Diego, CA |
| 1995 |
KENNARD, W., and LAPITAN, N.L.V. 1994. Progress towards the construction of a bacterial artificial chromosome library in barley. Barley Genetics Newsletter 24:28-31 LAPITAN, N.L., PEDAS, K., ISHIMARU, C.A. 1995. Molecular genetics of immunity to bacterial ring rot in Solanum acaule. Potato Association of America, 79th Annual Meeting, no. 77 NAMUTH, D.M., LAPITAN, N.L.V., GILL, K.S., GILL, B.S. 1994. Comparative RFLP mapping of Hordeum vulgare and Tirticum tauschii. Theor. Appl. Genet. 89:865-872 PEDAS, K. 1995. Bacterial ring rot immunity in wild potato Solanum acaule. M.S. Thesis, Colo State Univ., Fort Collins. Spring, 1995, 108 pp SHERMAN, J.D., FENWICK, A.L., NAMUTH, D.M., LAPITAN, N.L.V. 1995. A barley RFLP map: alignment of three barley maps and comparisons to Gramineae species. Theor. Appl. Genet. 91: 681-690 |
| 1996 |
LAPITAN, N. L. V. 1996. In situ hybridization in plant species with small chromosomes. IN: Plant Molecular Biology, M. CLARK (ed.). Springer-Verlag, Heidelberg, pp. 512-519 LAPITAN, N.L.V., BROWN, S.E., and KNUDSON, D.L. 1996. Physical mapping of barley. Plant Genome IV Meeting. Scherago International Inc., San Diego, CA., Abs. no. P145 NKONGOLO, K. K., LAPITAN, N. L. V., and QUICK, J. S. 1996. Genetic and cytogenetic analyses of Russian wheat aphid resistance in triticale x wheat hybrids and progenies. Crop Sci. 36:1114-1119 |
| 1997 |
BROWN, S.E., STEPHENS, J.L., KNUDSON, D.L., LAPITAN, N.L.V. 1997. Do the minor ribosomal DNA loci in barley contain 18S sequences? Plant and Animal Genome V Meeting, Scherago International Inc., San Diego, CA., Abstract no. P154 LAPITAN, N., MA, Z., STEFFENSON, B., RASMUSSON, D. 1997. DNA markers and germplasm for breeding of Fusarium head blight resistant six-rowed barley varieties. Annual Progress Report on Malting Barley Research. American Malting Barley Association, Milwaukee, WI. 13-24 LAPITAN, N.L.V., BROWN, S.E., KENNARD, W., STEPHENS, J.L., KNUDSON, D.L. 1996. FISH physical mapping with barley BAC clones. The Plant J. 11:149-156 LAPITAN, N.L.V., BROWN, S.E., STEPHENS, J. L., KNUDSON, D. L. 1997. FISH physical mapping in plant species with large genomes. Plant and Animal Genome V Meeting, Scherago International Inc., San Diego, CA., Abstract no. S22 (Invited talk) MA, Z. Q., SORRELLS, M.E., LAPITAN, N. 1997. Application of AFLP technology in wheat. Plant and Animal Genome V Meeting, Scherago International Inc., San Diego, CA., Abstract no.P78 MA, Z. Q., STEFFENSON, B.J., FROST, E.A., RASMUSSON, D.C., LAPITAN, N. 1997. QTL mapping of scab resistance genes in six-rowed barley. Plant and Animal Genome V Meeting, Scherago International Inc., San Diego, CA., Abstract no.P171 ROKKA, V M., CLARK, M., PIETILA, L., LAPITAN. N.L.V., PEHU, E. 1996. In situ hybridization of species specific repetitive DNA sequences of Solanum brevidens and S. tuberosum. In: EAPR Meeting Abstracts. Wageningen, The Netherlands, July 1996 ROKKA, V M., VALKONEN, J.P.T., LAPITAN. N.L.V., PIETILA, L., PEHU, E. 1996. Production of somatohaploids by anther culture of interspecific somatic hybrids and their potential in potato breeding and research. In: Third International Symposium on In Vitro Culture and Horticultural Breeding Abstracts, Israel, June 16-21 1996 STEPHENS, J.L., BROWN, S.E., KNUDSON, D.L., LAPITAN, N.L.V. 1997. FISH tags for barley chromosomes. Plant and Animal Genome V Meeting, Scherago International Inc., San Diego, CA., Abstract no. P179 |
| 1998 |
ERKER, B. 1998. Utility of molecular marker technology and inheritance of resistance of PI 262660 in breeding Russian wheat aphid resistant wheats. M. S. thesis. Colorado State University, Fort Collins, CO. 53 pp. LAPITAN, N.L.V. 1998. Using DNA markers to improve wheat and barley. Agronomy News, Cooperative Extension, Colorado State University, Fort Collins, CO. 18 (3): 2-3 MA, Z.-Q., and LAPITAN, N.L.V. 1998. A comparison of amplified and restriction fragment length polymorphism in wheat. Cereal Res. Comm. 26:7-13 MA, Z.-Q., SAIDI, A., QUICK, J.S., and LAPITAN, N.L.V. 1998. Genetic mapping of Russian wheat aphid resistance genes Dn2 and Dn4 in wheat. Genome 41:303-306 ROKKA, V.-M, CLARK, M.S., KNUDSON, D.L., PEHU, E., and LAPITAN, N.L. 1998. Cytological and molecular characterization of repetitive DNA sequences of Solanum brevidens and Solanum tuberosum. Genome 41:487-494 ROKKA, V.-M., ISHIMARU, C.A., LAPITAN, N.L.V., and PEHU, E. 1998. Production of androgenic dihaploid lines of the disomic tetraploid potato species Solanum acaule ssp. acaule. Plant Cell Reports 18: 89-93 |
| 1999 |
Boyko, E.V., Gill, K.S., Mickelson-Young, L., Nasuda, S., Raupp, W.J., Ziegle, J.S., Hassawi, D.S., Fritz, A.K., Namuth, D., Lapitan, N.L.V., and Gill, B.S. 1999. A high-density genetic linkage map of Aegilops tauschii, the D-genome progenitor of wheat. Theor. Appl. Genet. 99:16-26 Brown, S.E., Stephens, J.L., Lapitan, N.L.V., and Knudson, D.L. 1999. rDNA loci in barley and wheat: probe pTA71 FISH fact or fiction. Plant and Animal Genome VII Meeting Proceedings, San Diego California. P400, p.181 Brown, S.E., Stephens, J.L., Lapitan, N.L.V., and Knudson,D.L. 1999. FISH landmarks for barley chromosomes (Hordeum vulgare L.). Genome 42: 274-281 |
| 2000 |
Anderson, G.A., Miller, C.A., Papa, D., and Lapitan, N.L.V. 2000. Genetic mapping of Russian wheat aphid resistance gene Dn7, and higher marker density mapping of Dn2 and Dn4 in wheat. Plant and Animal Genome VIII Meeting, San Diego, CA. p.101 (Abstract). Ma, Z.-Q., Steffenson, B.J., Prom, L.K., and Lapitan, N.L.V. 2000. Mapping of quantitative trait loci for Fusarium head blight in barley. Phytopathology 90: 1079-1088. Papa, D., Miller, C.A. Anderson, G.A., Dubcovsky, J., Lagudah, E.S., Spielmayer, W., and Lapitan, N.L.V. 2000. FISH physical mapping of DNA sequences associated with RWA resistance in wheat and barley. Plant and Animal Genome VIII Meeting, San Diego, CA. p.60 (Abstract). Stephens, J.L., Brown, S.E., Lapitan, N.L.V. and Knudson, D.L. 2000. FISH mapping cDNAs to cereal chromosomes. Plant and Animal Genome VIII Meeting, San Diego, CA. p. 61 (Abstract). |
| 2001 |
Lapitan, N.L.V., Stephens, J.L., Brown, S.E. , Altinkut, A., and Knudson, D.L. 2001. Integration of the genetic and physical maps of barley and wheat based on FISH with cDNAs and BACs. Plant and Animal Genome IX Abstracts. p. 48. Miller, C.A., Altinkut, A., and Lapitan, N.L.V. 2001. A microsatellite marker for tagging Dn2, a gene conferring resistance to Russian wheat aphid in wheat. Crop Science 41:1584-1589. |
| 2002 |
Tahir, M., Lawrence, C., Lapitan, N.L.V. 2002. Characterization of differentially expressed cDNAs in response to Russian wheat aphid feeding in wheat. Plant and Animal Genome IX Abstracts, Plant and Animal Genome Meetings, San Diego, CA. p. 265. |
| 2003 |
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M., Dubcovsky, J., Hossain, K., Kianian, S. F., Miftahudin, Gustafson, J. P., Wennerlind, E., Anderson, J. A., Pathan, M. S., Nguyen, H. T., McGuire, P. E., Qualset, C. O., and Lapitan, N. L. V. 2003. A physical map of expressed sequence tags and functional genomics in the group 1 chromosomes of wheat Triticum aestivum. Proceedings of the 10th International Wheat Genetics Symposium 3: 1035-1037. Sorrells, M. E., La Rota, M., Bermudez-Kandianis, C. E., Greene, R. A., Kantety, R., Munkvold, J. D., Miftahudin, Mahmoud, A., Ma, X., Gustafson, J. P., Qi, L., Echalier, B., Gill, B. S., Matthews, D. E., Lazo, G. R., Chao, S., Anderson, O. D., Edwards, H., Linkiewicz, A. M., Dubcovsky, J., Akhunov, E. D., Dvorak, J., Zhang, D., Nguyen, H. T., Peng, J., Lapitan, N. L. V., Gonzalez-Hernandez, J., Anderson, J. A., Hossain, K., Kalavacharla, V., Kianian, S. F., Choi, D. W., Close, T. J., Dilbirligi, M., Gill, K. S., Steber, C., Walker-Simmons, M. K., McGuire, P. E., and Qualset, C. O. 2003. 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| 2004 |
Hossain, K.G., Kalavacharla, V., Lazo, G.R., et al. 2004. A chromosome bin map of 2148 expressed sequence tag loci of wheat homeologous group 7. Genetics 168: 687-699. Lazo, G.R., Chao, S., Hummel, D., et al. 2004. Development of an expressed sequence tag (EST) resource for wheat (Triticum aestivum L.): EST generation, unigene analysis, probe selection, and bioinformatics for a 16,000-locus bin-delineated map. Genetics 168: 585-593. Linkiewicz, A.M., Qi, L.L., Gill, B.S., Ratnasiri, A., et al. J. 2004. A 2500-locus bin map of wheat homeologous group 5 provides insights on gene distribution and colinearity with rice. Genetics 168: 665-676. Ma, Z., Lapitan, N.L.V. and Steffenson, B. 2004. QTL mapping of net blotch resistance genes in a doubled-haploid population of six-rowed barley. Euphytica 137: 291-296. Miftahudin, K Ross14, X.-F.M., Mahmoud, A., et al. 2004. Physical bin map of ESTs on wheat homoeologous group 4 chromosomes. In: Plant and Animal Genome XII, P407. Miftahudin, Ross, K., Ma, X.-F., Mahmoud, A.A., Layton, J., et al. 2004. Analysis of expressed sequence tag loci on wheat chromosome group 4. Genetics 168: 651-663. Munkvold, J.D., Greene, R.A., Bermudez-Kandianis, C.E., et al. 2004. Group 3 chromosome bin maps of wheat and their relationship to rice chromosome 1. Genetics 168: 639-650. Peng, J., Lazo, G.R. and Lapitan, N.L.V. 2004. Functional micro-colinearity of wheat group-1 chromosomes with the rice genome. In: Plant and Animal Genome XII, P172. Peng, J., Tahir, M., Wang, H. and Lapitan, N.L.V. 2004. Frequency and distribution of functional microsatellites in wheat, Triticum aestivum L. Plant and Animal Genome XII: P177. Peng, J.H., Zadeh, H., Lazo, G.R., et al., and Lapitan, N.L.V. 2004. Chromosome bin map of expressed sequence tags in homoeologous group 1 of hexaploid wheat and homoeology with rice and Arabidopsis. Genetics 168: 609-623. Qi, L., Echalier, B., Chao, S., Lazo, G., Anderson, O.D., et al. 2004. A physical map of 16 ,000 EST loci and chromosomal distribution of genes among the three genomes of polyploid wheat . Genetics 168: 701-712. Randhawa, H.S., Dilbirligi, M., Sidhu, D., et al. 2004. Deletion mapping of homeologous group 6-specific wheat expressed sequence tags. Genetics 168: 677-699. Randhawa, H.S., Dilbirligi, M., Sidhu, D., et al. 2004. Deletion mapping of homeologous group 6-specific wheat expressed sequence tags. Genetics 168: 677-699. Randhawa, H.S., Dilbirligi, M., Sidhu, D., et al. 2004. Deletion mapping of homeologous group 6-specific wheat expressed sequence tags. Genetics 168: 677-699. Soria, M.A., Khan, A., Anderson, A., Brown-Guedira, G., Campbell, K.G., Elias, E.M., Fritz, A .K., Gill, B.S., Gill, K.S., Haley, S., Kianian, S.F., Kidwell, K., Lapitan, N.L.V., Ohm, H., Sherman, J.D., Sorrells, M.E., Souza, E., Talbert, L. and Dubcovsky, J. 2004. The MASWheat project: bringing genomics to the wheat fields. In: Plant and Animal Genome XII, P126. Soria, M.A., Khan, A., Anderson, A., Brown-Guedira, G., Campbell, K.G., Elias, E.M., Fritz, A .K., Gill, B.S., Gill, K.S., Haley, S., Kianian, S.F., Kidwell, K., Lapitan, N.L.V., Ohm, H., Sherman, J.D., Sorrells, M.E., Souza, E., Talbert, L. and Dubcovsky, J. 2004. The MASWheat project: bringing genomics to the wheat fields. In: Plant and Animal Genome XII, P126. Soria, M.A., Khan, A., Anderson, A., Brown-Guedira, G., Campbell, K.G., Elias, E.M., Fritz, A .K., Gill, B.S., Gill, K.S., Haley, S., Kianian, S.F., Kidwell, K., Lapitan, N.L.V., Ohm, H., Sherman, J.D., Sorrells, M.E., Souza, E., Talbert, L. and Dubcovsky, J. 2004. The MASWheat project: bringing genomics to the wheat fields. In: Plant and Animal Genome XII, P126. Stephens, J.L., Brown, S.E., Lapitan, N.L.V. and Knudson, D.L. 2004. Physical mapping of barley genes using an ultrasensitive fluorescence in situ hybridization technique. Genome 47: 179-189. Tahir, M., Lawrence, C.B., Cooper, B., Wright, L. and Lapitan, N.L.V. 2004a. Molecular characterization of allelic variants of b-amylase in barley. In: Plant and Animal Genome XII, P112. Stephens, J.L., Brown, S.E., Lapitan, N.L.V. and Knudson, D.L. 2004. Physical mapping of barley genes using an ultrasensitive fluorescence in situ hybridization technique. Genome 47: 179-189. Stephens, J.L., Brown, S.E., Lapitan, N.L.V. and Knudson, D.L. 2004. Physical mapping of barley genes using an ultrasensitive fluorescence in situ hybridization technique. Genome 47: 179-189. Tahir, M., Sharma, V., Haley, S.D., Butler, J. and Lapitan, N.L.V. 2004b. High density mapping of a rye gene (Dn7) conferrring resistance to Russian wheat aphid in wheat. In: Plant and Animal Genome XII, San Diego, CA, P191. Conley, E.J., Nduati, V., Gonzalez-Hernandez, J.L., Mesfin, A., et al. 2004. A 2600-locus chromosome bin map of wheat homeologous group 2 reveals interstitial gene-rich islands and colinearity with rice. Genetics 168: 625-637. |
| 2005 |
Arzani, A., Peng, J.H. and Lapitan, N.L.V. 2004. DNA and morphological markers for a Russian wheat aphid resistance gene. Euphytica 139: 167-172. Botha-Oberholster, A.-M., Lapitan, N.L.V., Cooper, B., Wright, L., Menert, J., Close, T.J., Svensson, J.T., Rodriguez, E.M. and Lawrence, C. 2005. Transcriptional profiling of gene expression during malting in barley. Plant and Animal Genome Conference XIII: P664. Lapitan, N. and Jauhar, P. 2005. Molecular Markers, Genomics, and Genetic Engineering in Wheat . In: Singh, R. and Jauhar, P. (eds), Genetic Resources, Chromosome Engineering, and Crop Improvement: Cereals CRC Press Boca Raton, Florida. Lapitan, N.L., Botha-Oberholster, A.-M., Cooper, B., Menert, J., Close, T.J. and Lawrence, C. 2005. Functional genomics of malting in barley. Plant and Animal Genome Conference XIII: W039. Lapitan, N.L., Li, Y. and Botha-Oberholster, A.-M. 2005. The Russian wheat aphid and its interaction with wheat. Plant and Animal Genome Conference XIII: W262. Lapitan, N.L.V., Botha-Oberholster, A.-M., Close, T.J. and Lawrence, C. 2005. Transcriptional profiling of gene expression during malting in barley. In: Proc. of the North American Barley Researchers Meeting., Red Deer, Canada. Peng, J. and Lapitan, N.L.V. 2005. Characterization of EST-derived microsatellites in the wheat genome and development of eSSR markers. Funct. Integr. Genomics 5: 80-96. Sharma, V. 2005. Molecular Genetic Basis of Wheat Resistance to the Russian Wheat Aphid. Ph.D. Dissertation. Department of Soil and Crop Sciences. Colorado State University, Fort Collins, CO, 101 pages. Soria, M.A., Anderson, J.A., Brown-Guedira, G., Campbell, K.G., Elias, E.M., Fritz, A.K., Gill , B.S., Gill, K.S., Haley, S., Kianian, S.F., Kidwell, K., Lapitan, N.L.V., Ohm, H., Sherman, J.D., Sorrells, M.E., Souza, E., Talbert, L. and Dubcovsky, J. 2005. The MASwheat project. Impact of genomics on wheat breeding. Plant and Animal Genome XIII: P305. |
| 2006 |
Arzani, A., and Lapitan, N.L.V. 2006. Genetic variation for resistance to Russian wheat aphid F2-derived familes of wheat (Triticum aestivum L.). J. Agric. Sci. Technol. 9: 55-69. Botha, A.M., Li, Y., and Lapitan, N.L.V. 2006. Elicitation of the wheat defense-transcriptome in response to two Diuraphis noxia biotypes. In: 17th Biennial International Plant Resistance to Insects Workshop. Purdue University, West Lafayette, IN, p 46 Chao, S., Lazo, G.R., You, F., Crossman, C., C,, Hummel, D., D,, Lui, N., Laudencia-Chingcuanco, D., Anderson, J.A., Close, T.J., Dubcovsky, J., Gill, B.S., Gill, K.S., Gustafson, J.P., Kianian, S.F., Lapitan, N.L., Nguyen, H.T., Sorrells, M.E., McGuire, P.E., Qualset, C.O., and Anderson, O., D. 2006. Use of a large-scale Triticeae expressed sequence tag resource to reveal gene expression profiles in hexaploid wheat (Triticum aestivum L.). Genome 49: 531-544. Lapitan, N.L.V. 2006. Molecular approaches to understand wheat-insect interaction. In: Collaborative Plant Biology in the Rocky Mountain/Midwest: Impacts and Future Prospects for Plant Genomics. University of Wyoming, University of Wyoming, p 19 Lapitan, N.L.V., Li, Y., Peng, J., and Botha, A.-M. 2006. Deciphering the molecular interaction between wheat and the Russian wheat aphid. In: 17th Biennial International Plant Resistance to Insects Workshop. Purdue University, West Lafayette, IN, pp 45-46 Van Eck, L., Myburg, A., Lapitan, N.L.V., and Botha-Oberholster, A.M. 2006. Profiling Russian wheat aphid (Diuraphis noxia) induced transcripts in near isogenic wheat (Triticum aestivum L .) lines using cDNA-AFLP and quantitative PCR analysis. In: 17th Biennial International Plant Resistance to Insects Workshop. Purdue University, p 27 |