Source: NORTH DAKOTA STATE UNIV submitted to
ENABLING US WHEATS FOR HOMOEOLOGOUS RECOMBINATION-BASED GENE INTROGRESSION
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1007990
Grant No.
2016-67014-24455
Project No.
ND05064
Proposal No.
2015-05781
Multistate No.
(N/A)
Program Code
A1141
Project Start Date
Nov 1, 2015
Project End Date
Apr 30, 2019
Grant Year
2016
Project Director
Cai, X.
Recipient Organization
NORTH DAKOTA STATE UNIV
(N/A)
FARGO,ND 58105
Performing Department
Plant Sciences
Non Technical Summary
Wheat is a major food crop in the US. Wheat production has been continually threatened by various biotic and abiotic stresses. There is a constant need to find and deploy new genes in wheat to strengthen its defense against new threats. However, wheat has limited genetic variability due tothe nature oforigin, which has increasingly become a bottleneck for wheat improvement. It is essential to bring new genes into wheat to expand its genetic variability. The wild grass relatives of wheat represent an invaluable gene pool for wheat improvement. Favorable genes of wild grass relatives can be incorporated into wheat by ph1b mutant-induced homoeologous meiotic recombination. However, the ph1b mutant, originally developed in the old Chinese wheat landrace 'Chinese Spring' (CS) with poor agronomic characteristics, has not been deployed in most classes of US wheats. Here we propose to deploy the ph1b system in the US wheat and build an effective pipeline of gene flow from wild grasses into US wheats. The specific objectives of this project are to: 1) Incorporate CS ph1b mutant into US wheats for homoeologous recombination-based geneintrogression (HRBGI);and 2) Develop ph1b mutant-specific molecular markers to improve the efficacy of the mutant inHRBGI.Ultimately, this research will enable US wheats for HRBGI and create an operative entrance of alien genes into US wheats for germplasm and variety development.
Animal Health Component
0%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2021549108060%
2021549108140%
Knowledge Area
202 - Plant Genetic Resources;

Subject Of Investigation
1549 - Wheat, general/other;

Field Of Science
1081 - Breeding; 1080 - Genetics;
Goals / Objectives
Wild relatives of wheat represent an invaluable gene reservoir for wheat improvement. One of the approaches for expanding the genetic variability of wheat is to bridge gene flow from the wild relatives into wheat by inducing meiotic recombination between homoeologues of wheat and the relatives. Wheat, however, has a defense system against homoeologous meiotic pairing/recombination, which is controlled predominantly by the Ph1 (pairing homoeologous) gene on the long arm of chromosome 5B (5BL). The Ph1 gene prevents homoeologous chromosomes from pairing and recombining in meiosis, and therefore restricts homoeologous recombination-based gene introgression (HRBGI). Over the last few decades, the Ph1-controlled defense system has been manipulated to induce homoeologous pairing/recombination for gene introgression from wild grasses into wheat. A large deletion (~70 Mb) encompassing the Ph1 locus on 5BL, designated ph1b, was generated by X-ray irradiation in the old Chinese common wheat landrace 'Chinese Spring' (CS) with poor agronomic characteristics. Deletion of the Ph1 locus, i.e. ph1b mutant, induces meiotic pairing and recombination between homoeologues of wheat and related wild grasses. The ph1b mutant has been widely used in HRBGI from wheat-related grass species into wheat. However, the unadapted CS background and the laborious process of removing the ph1b deletion from resultant homoeologous recombinants have limited the efficacy of this mutant in gene introgression and germplasm development. Theprimarygoals of this project are to develop an effective ph1b system in the US wheat for homoeologous recombination-based gene introgression (HRBGI) from wheat-related wild grass species directly into major classes of US wheats and todevelop ph1b deletion-specific molecular markers for quick identification/removal of the deletionin theresultant homoeologous recombinants for germplasm development. The specific objectives of this project are to:Incorporate CS ph1b mutant into five classes of US wheats for HRBGI; and 2. Develop ph1b mutant-specific molecular markers to improve the efficacy of the mutant in HRBGI.
Project Methods
The original ph1b deletion mutant was developed in the Chinese spring wheat cultivar 'Chinese Spring' (CS) that has poor agronomic characteristics. We will incorporate CS ph1b deletion into five major classes of US wheats by a molecular marker-assisted backcross strategy. This strategy primarily uses the hemizygote (Ph1ph1b), instead of ph1bph1b, to carry the ph1b deletion through generations. This minimizes use of the homozygous deletion (ph1bph1b) that induces meiotic pairing/recombination between homoeologues in three wheat sub-genomes and then causes genomic instability.Thus, this strategy largely maintains the integrity of the defense system against homoeologous meiotic recombination in most steps of the introgression process.Consequently, this will help ensure genome integrity of the US wheat recipients by preventing inter-subgenomic homoeologous recombination and will incorporate the ph1b deletion into a largely unchanged US wheat background.The US wheatswith ph1b deletion incorporated will be verified and assessed for their activity in inducing homoeologousrecombination by investigating meiotic pairing between homoeologous chromosomes. The US wheat ph1b mutants with confirmed ph1b activity will be released to the wheat research community for use in HRBGI and other studies. The ph1b deletion was physically positioned near the middle of chromosome arm 5BL and was estimated to encompass a genomic region of approximately 70 Mb. Comparative and deletion mapping identified rice and Brachypodium genomic regions collinear with the wheat genomic region spanning the Ph1 locus on 5BL. In addition, molecular marker loci have been detected within and outside of the ph1b deletion region. However, the breakpoints of the CS ph1b deletion have not been precisely demarcated on 5BL.Wewill genotype chromosome 5B of CS and the CS ph1b mutant using the wheat 90K SNP array and identified the genomic region encompassing the Ph1 locus as well as nearby regions. Also, we may perform further comparative analysis of the genomic region spanning the Ph1 locus and its collinear counterparts in rice and Brachypodium genomes to detect the breakpoints of the deletion. This will allow for the development of molecular markers that define the breakpoints of the ph1b deletion.These markerswill be verified for utility in HRBGI and germplasm development prior to release to the public.

Progress 11/01/15 to 04/30/19

Outputs
Target Audience:One undergraduate student and one postdoctoral researcher have participated in this research project. They have received extensive training in molecular cytogenetics, genomics, and high-throughput genotyping technology. In addition, they have learned new technologies we have developed in chromosome engineering and genome manipulation and characterization in this project. Also, we have brought the results and discoveries obtained in this project into the graduate cytogenetics class (PLSC 741) to help students understand how the genomics technologies and resources benefit cytogenetic studies on chromosome variation and engineering. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One postdoctoral research scientist, one graduate student, one undergraduate student, and one research specialist have participated in this research project. They have received extensive training in molecular cytogenetic and high-throughput genotyping technologies in the lab. The research personnel have presented the results of this project in the Plant and Animal Genome conference in San Diego, CA January 2018. How have the results been disseminated to communities of interest?Research results and strategies of this project have been presented in the international scientific conference (Plant and Animal Genome conference) and to the commodity groups, such as ND Wheat Commission, to help wheat growers understandn the significance and impact of this research on wheat production. A manuscript about this work was published in an internationally-respected plant genetics and breeding journal in 2019. Another manuscript about ph1b introgression is under preparation and will be submitted for publication in an international scientific journal. Also, we have used some of the research materials and results in the genetics and cytogenetics classes to enhance students learning of chromosome engineering and its application in crop improvement. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Wheat has a narrow genetic basis due to its polyploid origin. But it has a large number of wild grass relatives useful in enriching and diversifying the wheat genome. It is difficult to utilize the wild grass gene pool directly in wheat breeding for variety development because of the genetic differences between wheat and the wild grasses. Pre-breeding efforts are needed to overcome the biological barriers for gene transfer from wild grasses into wheat. The most feasible approach for that is to induce genetic exchange between wheat and wild grasses using the ph1b genetic system. Unfortunately, the ph1b genetic system is available only in the old spring wheat landrace 'Chinese Spring' (CS) with poor agronomic performance. This has limited the utility of this genetic system in gene transfer from wild grasses into wheat. In this project, we introduced the ph1b system into the major classes of US wheats from CS. This will bridge the gene flow from wild grasses directly into US wheats and expand the genetic basis of US wheats. Molecular markers are the useful tools for the characterization and utilization of the genes targeted in wheat breeding and germplasm development. They have been widely used to assist selection of specific genes in wheat breeding and genetic studies. In this project, we developed ph1b mutant-specific molecular markers to assist selection of the ph1b mutant in pre-breeding and germplasm development. These molecular markers improve the efficacy and throughput of the ph1b system in gene transfer from wild grasses to wheat, and facilitate utilization of the wild grass gene pool in wheat improvement. We are extremely happy to see that this research project has been successfully accomplished exactly as we planned and expected in the proposal. Following are the detailed accomplishments under each of the research objectives in this project. Objective 1: Incorporate CS ph1b mutant into US wheats for homoeologous recombination-based gene introgression (HRBGI) We transferred the CS-derived ph1b mutant (deletion) into seven modern varieties under the five major US wheat classes, including the soft red winter wheat 'SS 8641' (GA) and 'Pembroke 14 (KY), soft white winter wheat 'Otto' (WA) and 'Jasper' (WA), hard white spring wheat 'Argent' (ND), hard red spring wheat 'Alsen' (ND), and durum wheat 'Divide' (ND). They were initially crossed to CS ph1b mutant, and the resultant F1 hybrids were self-pollinated to produce homozygous ph1b mutant for backcrossing with the respective US wheat parents. The same procedure was followed in the successive backcrosses. To date, we developed homozygous ph1b mutant of 'Alsen', 'Argent', and 'Divide' from their respective BC3F2 populations. They exhibit similar meiotic pairing as CS ph1b mutant according to our preliminary results. In addition, we advanced the generation of the BC3F1 introgression populations involving the winter wheat varieties 'SS 8641', 'Pembroke 14', 'Otto', and 'Jasper' and the spring wheat 'Line E' (a common wheat line universally susceptible to all stem rust races), and are selecting homozygous ph1b mutant of the winter wheat varieties from the BC3F2 populations. The ph1b deletion-specific molecular markers we developed in this project have been used in the selection of the ph1b deletion in the last backcross and self-pollination generations. This has significantly accelerated the ph1b introgression process in this project, especially for winter wheat. By the end of 2019, we will have the homozygous ph1b mutants of all these U.S. wheat varieties available to the wheat research community for uses in breeding and genetic studies. Objective 2: Develop ph1b mutant-specific molecular markers to improve the efficacy of the mutant in HRBGI The ph1b mutant resulted from a large deletion of the genomic region harboring the Ph1 locus on the short arm of wheat chromosome 5B (5BL). The molecular markers specific for the Ph1 locus are available, but not for the ph1b deletion in the wheat research community worldwide. This has limited the utility of the ph1b mutant in the meiotic homoeologous recombination-based gene introgression and genome studies in wheat and its relatives. In this project, we first anchored the ph1b deletion on 5BL by wheat 90K SNP assay, and then delimited the deletion to a genomic region of 60,014,523 bp by chromosome walking. The nucleotide positions of both distal and proximal breakpoints (DB and PB) were identified for the ph1b deletion. This will facilitate understanding of the genetic and molecular mechanism underlying the Ph1 activity in wheat. Meanwhile, we developed user-friendly molecular markers specific for the ph1b deletion based on the DNA sequences of the genomic regions immediately proximal to PB and distal to DB. These new ph1b deletion-specific markers will dramatically improve the efficacy and throughput of the ph1b mutant in alien gene introgression from wild grasses into wheat and homoeologous recombination-based genome studies in wheat and its relatives. In addition, these markers have been effectively used to assist selection in the transfer of the ph1b deletion from CS to the adapted US wheat genotypes in this project. This objective has been successfully accomplished exactly as we proposed. This work was published and appreciated by reviewers and wheat researchers.

Publications

  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Gyawali Y., Zhang W., Chao S., Xu S. S., and Cai X. 2019. Delimitation of wheat ph1b deletion and development of ph1b-specific DNA markers. Theor Appl Genet 132:195204 (https://doi.org/10.1007/s00122-018-3207-2).
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Zhang, W., Zhang, M., Zhu, X., Cao, Y., Sun, Q., Ma, G. Chao, S., Yan, C., Xu, S., and Cai, X. 2018. Molecular cytogenetic and genomic analyses reveal new insights into the origin of the wheat B genome. Theor Appl Genet 131: 365375.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Zhang, W., Zhu, X., Zhang, M., Chao, S., Xu, S., and Cai, X. 2018. Meiotic homoeologous recombination-based mapping of wheat chromosome 2B and its homoeologues in Aegilops speltoides and Thinopyrum elongatum. Theor Appl Genet 131:23812395.
  • Type: Book Chapters Status: Awaiting Publication Year Published: 2019 Citation: Zhang, W., and Cai, X. 2018. Alien Introgression and breeding of synthetic wheat. In: Advances in Breeding Techniques for Cereal Crops. Ed by Frank Ordon and Wolfgang Friedt. Burleigh Dodds Science Publishing.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Zhang, W., Cao, Y., Zhang,M., Zhu, X., Ren, S., Long, Y., Gyawali, Y., Chao, S., Xu, S., and Cai, X. 2017. Meiotic homoeologous recombination-based alien gene introgression in the genomics era of wheat. Crop Sci 57: 1189-1198 (Crop Wild Relatives Special Section).
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Ma, G., Zhang, W., Liu, L., Chao, W. S., Gu, Y., Qi, L., Xu, S. S., and Cai, X. 2018. Cloning and characterization of the homoeologous genes for the Rec8-like meiotic cohesin in polyploid wheat. BMC Plant Biology 18:224; https://doi.org/10.1186/s12870-018-1442-y.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Boehm, J. D., Zhang, M., Cai, X., and Morris, C. F. 2017. Molecular and cytogenetic characterization of the 5DS-5BS chromosome translocation conditioning soft kernel texture in durum wheat. Plant Genome 10: 1-11
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Somo, M., Pirseyedi, S.-M., Cai, X., and Marais, F. 2017. Modified versions of the Lr62 translocation of wheat. Crop Sci. 57: 18981905.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Curwen-McAdams, C., Arterburn, M., Murphy, K., Cai, X., and Jones, S.S. 2017. Toward a taxonomic definition of perennial wheat: A new species �Tritipyrum aaseae described. Genetic Resources and Crop Evolution 64: 16511659.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Niu, Z., Chao, S., Cai, X., Whetten, R., Breiland, M., Cowger, C., Chen, X., Friebe, B., Gill, B. S., Rasmussen, J., Klindworth, D. L., and Xu, S. S. 2018. Molecular and cytogenetic characterization of six wheat-Aegilops markgrafii disomic addition lines and their resistance to rusts and powdery mildew. Front Plant Sci 9: 1616; doi: 10.3389/fpls.2018.01616.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Szabo-Hever, A., Zhang, Q., Friesen, T. L., Zhong, S., Elias, E. M., Cai, X., Jin, Y., Faris, J. D., Chao, S., and Xu, S. S. 2018. Enhanced resistance to Fusarium head blight in synthetic hexaploid wheats derived from Aegilops tauschii and diverse Triticum turgidum subspecies. Front Plant Sci; https://doi.org/10.3389/fpls.2018.01829.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Zhang, W., Zhang, M., Cao, Y., Zhu, X., Ren, S., Long, Y., Gyawali, Y., Chao, S., Xu, S.S., and Cai, X. 2017. Enriching and understanding the wheat B genome by meiotic homoeologous recombination. Joint Conference of the National Association of Plant Breeders Annual Meeting and the USDA/NIFA Annual PD Workshop, UC at Davis, CA, August 7-10, 2017.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Zhang, W., Zhang, M., Zhu, X., Cao, Y., Ren, S., Long, Y., Gyawali, Y., Chao, S., Xu, S.S., and Cai, X. 2017. Alien Gene Introgression in the Genomics Era of Wheat (poster). Plant & Animal Genome XXV, San Diego, CA, January 14-18, 2017.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Zhang, W., Zhang, M., Zhu, X., Cao, Y., Sun, Q., Ma, G., Chao, S., Yan, C., Xu, S.S., and Cai, X. 2018. Genome-wide homology analysis reveals new insights into the origin of the wheat B genome (poster). Plant & Animal Genome XXVI, San Diego, CA, January 13-17, 2018.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gyawali, Y., Zhang, W., and Cai, X. 2018. Delimitation of wheat ph1b deletion and development of the ph1b-specific DNA markers (poster). Plant & Animal Genome XXVI, San Diego, CA, January 13-17, 2018.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Zhang, W., Zhu, X., Zhang, M., Shi, G., Liu, Z., and Cai, X. 2019. Chromosome engineering-mediated molecular mapping and introgression of novel Aegilops speltoides-derived resistance genes for tan spot and Septoria nodorum blotch diseases in wheat (poster). Plant & Animal Genome XXVII, San Diego, CA, January 12-16, 2019.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Cai, X., Zhang, W., Zhang, M., Gyawali, Y., Zhu, X., Cao, Y., Naraghi, S. M., Ren, S., Long, Y., Shi, G., Zhang, Q., Sun, Q., Ma, G., Liu, Z., Yan, C., Chao, S., and Xu, S. S. 2019. Diversification and understanding of the wheat B genome by homoeologous recombination and comparative genome analysis (poster). Proc. 1st Intern. Wheat Congress, Saskatoon, Canada. July 21-26, 2019.
  • Type: Journal Articles Status: Under Review Year Published: 2019 Citation: Zhang, W., Zhu, X., Zhang, M., Shi, G., Liu, Z., and Cai, X. 2019. Chromosome engineering-mediated introgression and molecular mapping of novel Aegilops speltoides-derived resistance genes for tan spot and Septoria nodorum blotch diseases in wheat. Theor Appl Genet (under review).


Progress 11/01/17 to 10/31/18

Outputs
Target Audience: One undergraduate student and one postdoctoral researcher have participated in this research project. They have received extensive training in molecular cytogenetics, genomics, and high-throughput genotyping technology. In addition, they have learned new technologies we have developed in chromosome engineering and genome manipulation and characterization in this project. Also, we have brought the results and discoveries obtained in this project into the graduate cytogenetics class (PLSC 741) to help students understand how the genomics technologies and resources benefit cytogenetic studies on chromosome variation and engineering. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One postdoctoral research scientist, one graduate student, one undergraduate student, and one research specialist have participated in this research project. They have received extensive training in molecular cytogenetic and high-throughput genotyping technologies in the lab. The research personnel have presented the results of this project in the Plant and Animal Genome conference in San Diego, CA January 2018. How have the results been disseminated to communities of interest?Research results and strategies of this project have been presented in the international scientific conference (Plant and Animal Genome conference) and to the commodity groups, such as ND Wheat Commission, to help wheat growers understandn the significance and impact of this research on wheat production. A manuscript about this work was published and another one for ph1b introgression will be published in an international scientific journal. Also, we have used some of the research materials and results in the genetics and cytogenetics classes to enhance students learning of chromosome engineering and its application in crop improvement. What do you plan to do during the next reporting period to accomplish the goals?The second objectives has been accomplished exactly as we proposed. Also, we anticipate the first objective (i.e. ph1b introgression) will be achieved as we proposed. We will continue making efforts toward the final goals in the following areas: 1. Advancing the generation of the BC3F1 introgression populations involving the winter wheat varieties 'SS 8641', 'Pembroke 14', 'Otto', and 'Jasper' and the spring wheat 'Line E' and select homozygous ph1b mutant of these wheat varieties from the BC3F2 populations using molecular markers; 2. Examine the advanced introgression lines for ph1b activity by performing meiotic pairing analysis; 3. Develop US wheat germplasm with confirmed ph1b activity; 4. Validate the molecular markers specific for the ph1b deletion in CS and the US wheat backgrounds; 5. Train the postdoctoral research fellow and graduate students; 6. Publish and present research results; 7. Release the ph1b-specific molecular markers and the US wheat germplasm containing the ph1b deletion.

Impacts
What was accomplished under these goals? Wheat has a narrow genetic basis due to its polyploid origin. But it has a large number of wild grass relatives useful in enriching and diversifying the wheat genome. It is difficult to utilize the wild grass gene pool directly in wheat breeding for variety development because of the genetic differences between wheat and the wild grasses. Pre-breeding efforts are needed to overcome the biological barriers for gene transfer from wild grasses into wheat. The most feasible approach for that is to induce the genetic exchange between wheat and wild grasses using the ph1b genetic system. Unfortunately, the ph1b genetic system is available only in the old spring wheat landrace 'Chinese Spring' (CS) with poor agronomic performance. This has limited the utility of this genetic system in gene transfer from wild grasses into wheat. In this project, we have introduced the ph1b system into the major classes of US wheats from CS. This will bridge the gene flow from wild grasses directly into US wheats and expand the genetic basis of US wheats. Molecular markers are the useful tools for the characterization and utilization of the genes targeted in wheat breeding and germplasm development. They have been widely used to assist selection of specific genes in wheat breeding and genetic studies. In this project, we have developed ph1b mutant-specific molecular markers to assist selection of the ph1b mutant in pre-breeding and germplasm development. These molecular markers improve the efficacy of the ph1b system in gene transfer from wild grasses to wheat, and facilitate utilization of the wild grass gene pool in wheat improvement. Following are the detailed accomplishments under each of the research objectives in this project. Objective 1: Incorporate CS ph1b mutant into US wheats for homoeologous recombination-based gene introgression (HRBGI) We have transferred the CS-derived ph1b mutant (deletion) into seven modern varieties under the five major US wheat classes, including the soft red winter wheat 'SS 8641' (GA) and 'Pembroke 14 (KY), soft white winter wheat 'Otto' (WA) and 'Jasper' (WA), hard white spring wheat 'Argent' (ND), hard red spring wheat 'Alsen' (ND), and durum wheat 'Divide' (ND). They were initially crossed to CS ph1b mutant, and the resultant F1 hybrids were self-pollinated to produce homozygous ph1b mutant for backcrossing with the respective US wheat parents. The same procedure was followed in the successive backcrosses. To date, we have developed homozygous ph1b mutant of 'Alsen', 'Argent', and 'Divide' from their respective BC3F1 populations. They exhibit similar meiotic pairing as CS ph1b mutant according to our preliminary results. Currently, we are advancing the generation of the BC3F1 introgression populations involving the winter wheat varieties 'SS 8641', 'Pembroke 14', 'Otto', and 'Jasper' and the spring wheat 'Line E' (a common wheat line universally susceptible to all stem rust races). The homozygous ph1b mutant of these wheat varieties will be selected from the BC3F2 populations. The ph1b deletion-specific molecular markers we developed in this project have been used in the selection of the ph1b deletion in the last backcross and self-pollination generations. This has significantly accelerated the ph1b introgression process in this project, especially for winter wheat. At the end of this project (April 2019), we should be able to obtain homozygous ph1b mutant of all these U.S. wheat varieties and release them to the wheat research community for uses in breeding and genetic studies. Objective 2: Develop ph1b mutant-specific molecular markers to improve the efficacy of the mutant in HRBGI The ph1b mutant resulted from a large deletion of the genomic region harboring the Ph1 locus on the short arm of wheat chromosome 5B (5BL). The molecular markers specific for the Ph1 locus are available, but not for the ph1b deletion in the wheat research community. This has limited the utility of the ph1b mutant in the meiotic homoeologous recombination-based gene introgression and genome studies in wheat and its relatives. In this project, we first anchored the ph1b deletion on 5BL by wheat 90K SNP assay, and then delimited the deletion to a genomic region of 60,014,523 bp by chromosome walking. The nucleotide positions of both distal and proximal breakpoints (DB and PB) were identified for the ph1b deletion. This will facilitate understanding of the genetic and molecular mechanism underlying the Ph1 activity in wheat. Meanwhile, we have developed user-friendly molecular markers specific for the ph1b deletion based on the DNA sequences of the genomic regions immediately proximal to PB and distal to DB. These new ph1b deletion-specific markers dramatically improves the efficacy of the ph1b mutant in alien gene introgression from wild grasses into wheat and homoeologous recombination-based genome studies in wheat and its relatives. In addition, these markers have been effectively used to assist selection in the transfer of the ph1b deletion from CS to the adapted US wheat genotypes in this project. This objective has been accomplished exactly as we proposed. This work has been published and appreciated by reviewers and readers.

Publications

  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Gyawali Y., Zhang W., Chao S., Xu S. S., and Cai X. 2018. Delimitation of wheat ph1b deletion and development of ph1b-specific DNA markers. Theor Appl Genet. https://doi.org/10.1007/s00122-018-3207-2
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Zhang, W., Zhang, M., Zhu, X., Cao, Y., Sun, Q., Ma, G. Chao, S., Yan, C., Xu, S., and Cai, X. 2018. Molecular cytogenetic and genomic analyses reveal new insights into the origin of the wheat B genome. Theor Appl Genet 131: 365⿿375.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Zhang, W., Zhu, X., Zhang, M., Chao, S., Xu, S., and Cai, X. 2018. Meiotic homoeologous recombination-based mapping of wheat chromosome 2B and its homoeologues in Aegilops speltoides and Thinopyrum elongatum. Theor Appl Genet 131:2381⿿2395.
  • Type: Book Chapters Status: Awaiting Publication Year Published: 2018 Citation: Zhang, W., and Cai, X. 2018. Alien Introgression and breeding of synthetic wheat. In: Advances in Breeding Techniques for Cereal Crops. Ed by Frank Ordon and Wolfgang Friedt. Burleigh Dodds Science Publishing.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Zhang, W., Cao, Y., Zhang,M., Zhu, X., Ren, S., Long, Y., Gyawali, Y., Chao, S., Xu, S., and Cai, X. 2017. Meiotic homoeologous recombination-based alien gene introgression in the genomics era of wheat. Crop Sci 57: 1189-1198 (Crop Wild Relatives Special Section).
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Ma, G., Zhang, W., Liu, L., Chao, W. S., Gu, Y., Qi, L., Xu, S. S., and Cai, X. 2018. Cloning and characterization of the homoeologous genes for the Rec8-like meiotic cohesin in polyploid wheat. BMC Plant Biology 18:224; https://doi.org/10.1186/s12870-018-1442-y.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Boehm, J. D., Zhang, M., Cai, X., and Morris, C. F. 2017. Molecular and cytogenetic characterization of the 5DS-5BS chromosome translocation conditioning soft kernel texture in durum wheat. Plant Genome 10: 1-11
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Somo, M., Pirseyedi, S.-M., Cai, X., and Marais, F. 2017. Modified versions of the Lr62 translocation of wheat. Crop Sci. 57: 1898⿿1905.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Curwen-McAdams, C., Arterburn, M., Murphy, K., Cai, X., and Jones, S.S. 2017. Toward a taxonomic definition of perennial wheat: A new species ÿTritipyrum aaseae described. Genetic Resources and Crop Evolution 64: 1651⿿1659.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2018 Citation: Niu, Z., Chao, S., Cai, X., Whetten, R., Breiland, M., Cowger, C., Chen, X., Friebe, B., Gill, B. S., Rasmussen, J., Klindworth, D. L., and Xu, S. S. 2018. Molecular and cytogenetic characterization of six wheat-Aegilops markgrafii disomic addition lines and their resistance to rusts and powdery mildew. Frontiers in Plant Science.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2018 Citation: Szabo-Hever, A., Zhang, Q., Friesen, T. L., Zhong, S., Elias, E. M., Cai, X., Jin, Y., Faris, J. D., Chao, S., and Xu, S. S. 2018. Enhanced resistance to Fusarium head blight in synthetic hexaploid wheats derived from Aegilops tauschii and diverse Triticum turgidum subspecies. Frontiers in Plant Science.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Zhang, W., Zhang, M., Cao, Y., Zhu, X., Ren, S., Long, Y., Gyawali, Y., Chao, S., Xu, S.S., and Cai, X. 2017. Enriching and understanding the wheat B genome by meiotic homoeologous recombination. Joint Conference of the National Association of Plant Breeders Annual Meeting and the USDA/NIFA Annual PD Workshop, UC at Davis, CA, August 7-10, 2017.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Zhang, W., Zhang, M., Zhu, X., Cao, Y., Ren, S., Long, Y., Gyawali, Y., Chao, S., Xu, S.S., and Cai, X. 2017. Alien Gene Introgression in the Genomics Era of Wheat (poster). Plant & Animal Genome XXV, San Diego, CA, January 14-18, 2017.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Zhang, W., Zhang, M., Zhu, X., Cao, Y., Sun, Q., Ma, G., Chao, S., Yan, C., Xu, S.S., and Cai, X. 2018. Genome-wide homology analysis reveals new insights into the origin of the wheat B genome (poster). Plant & Animal Genome XXVI, San Diego, CA, January 13-17, 2018.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gyawali, Y., Zhang, W., and Cai, X. 2018. Delimitation of wheat ph1b deletion and development of the ph1b-specific DNA markers (poster). Plant & Animal Genome XXVI, San Diego, CA, January 13-17, 2018.
  • Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2019 Citation: Zhang, W., Zhu, X., Zhang, M., Shi, G., Liu, Z., and Cai, X. 2019. Chromosome engineering-mediated molecular mapping and introgression of novel Aegilops speltoides-derived resistance genes for tan spot and Septoria nodorum blotch diseases in wheat (poster). Plant & Animal Genome XXVII, San Diego, CA, January 12-16, 2019.


Progress 11/01/16 to 10/31/17

Outputs
Target Audience:One undergraduate student, one graduate student, and one postdoctoral researcher have participated in this research project. They have received extensive training in molecular cytogenetics, genomics, and high-throughput genotyping technology. In addition, they have learned new technologies we have developed in chromosome engineering and genome manipulation and characterization in this project. Also, we will bring the results and discoveries we have obtained in this project into the graduate cytogenetics class (PLSC 741) to help students understand how the genomics technologies and resources benefit cytogenetic studies on chromosome variation and engineering. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One postdoctoral research scientist, one graduate student, one undergraduate student, and one research specialist (technician) have participated in this research project. They have received extensive training in molecular cytogenetic and high-throughput genotyping technologies in the lab. The research personnel will present the results of this project in the Plant and Animal Genome conference in San Diego, CA January 2018. How have the results been disseminated to communities of interest?Research results and strategies of this project have been presented in the international scientific conference (Plant and Animal Genome conference) and to the commodity groups, such as ND Wheat Commission, to help wheat growers understand the significance and impact of this research on wheat production. A manuscript about this work is under preparation, which is expected to be published in an international scientific journal in a few months. Also, we have used some of the research materials and results in the genetics classes to enhance students learning of chromosome engineering and its application in crop improvement. What do you plan to do during the next reporting period to accomplish the goals?We have made significant progress toward the research goals over the last two years of the project. We will continue making efforts toward the research goals in the following areas: 1. Continue making backcrosses to recover US wheat genetic backgrounds and retain ph1b deletion in the introgresion materials using molecular markers; 2. Examine the advanced introgression lines for ph1b activity by performing meiotic pairing analysis; 3. Develop US wheat germplasm with confirmed ph1b activity; 4. Annotate and analyze the genomic region harboring the Ph1 locus based the chromosome walking results we have obtained in this project; 5. Validate the molecular markers specific for the ph1b deletion in CS and the US wheat backgrounds; 6. Train the postdoctoral research fellow and graduate students; 7. Publish and present research results; 8. Release the ph1b-specific molecular markers and the US wheat germplasm containing the ph1b deletion.

Impacts
What was accomplished under these goals? Wheat has a narrow genetic variability due to the polyploid origin of its genome, but it has a large number of wild grass relatives useful in wheat improvement. They represent an invaluable gene pool to extent the genetic variability of wheat. However, it is difficult to utilize the wild grass gene pool directly in wheat breeding for variety development because of the genetic differences between wheat and the wild grasses. Pre-breeding efforts are needed to overcome the biological barriers for gene transfer from wild grasses into wheat. The most feasible approach for that is to enhance the genetic exchange between wheat and wild grasses using the ph1b genetic system. Unfortunately, the ph1b genetic system is available only in the old spring wheat landrace 'Chinese Spring' (CS) with poor agronomic performance. This has limited the utility of this genetic system in gene transfer from wild grasses into wheat. In this project, we have been introducing the ph1b system into the major classes of US wheats from CS. This will bridge the gene flow from wild grasses directly into US wheats and expand the genetic basis of US wheats. Molecular markers are the useful tools for the characterization and utilization of the genes targeted in wheat breeding and germplasm development. They have been widely used to assist selection of specific genes in wheat breeding and various wheat genetic studies. In this project, we have developed ph1b mutant-specific molecular markers to assist selection of the ph1b mutant in pre-breeding and germplasm development. These molecular markers will improve the efficacy of the ph1b system in gene transfer from wild grasses to wheat, and facilitate utilization of the wild grass gene pool in wheat improvement. Following are the detailed accomplishments under each of the research objectives in the first two years of this project. Objective 1: Incorporate CS ph1b mutant into US wheats for homoeologous recombination-based gene introgression (HRBGI) A total of seven varieties under the five major US wheat classes have been used as recipients for ph1b introgression, including the soft red winter wheat 'SS 8641' (GA) and 'Pembroke 14 (KY), soft white winter wheat 'Otto' (WA) and 'Jasper' (WA), hard white spring wheat 'Argent' (ND), hard red spring wheat 'Alsen' (ND), and durum wheat 'Divide' (ND). We crossed these US wheat varieties to CS ph1b mutant, and the resultant F1 hybrids were self-pollinated to produce homozygous ph1b mutant for backcrossing with the respective US wheat parents. To date, we have produced BC2F2 populations for the spring wheat recipients to select homozygous ph1b individuals for the third round of backcross. For the winter wheat recipients, BC1F2 populations have been produced to select homozygous ph1b individuals for the second round of backcross. Recently, we have developed new ph1b deletion-specific molecular markers, which were not available before. Currently, we have been using these newly developed markers to expedite the ph1b introgression process by skipping the self-pollinated generation. In addition, we have been transferring ph1b mutant to a bread wheat line (Line E) that is universally susceptible to all stem rust races following the same introgression procedure. Wild relatives of wheat represent an invaluable gene pool for wheat improvement. Many of the stem rust resistance genes in wheat are derived from wheat-related wild grasses. Incorporating ph1b mutant into this wheat line will facilitate genetic and pathological studies of newly identified stem rust resistance genes from wild grasses. Also, this will enhance utilization of the new resistance genes in wheat breeding and germplasm development. Objective 2: Develop ph1b mutant-specific molecular markers to improve the efficacy of the mutant in HRBGI The ph1b mutant resulted from a large deletion of the genomic region harboring the Ph1 locus on the short arm of wheat chromosome 5B (5BL). The molecular markers specific for the Ph1 locus are available, but not for the ph1b deletion in the wheat research community. This has limited the utility of the ph1b mutant in the meiotic homoeologous recombination-based gene introgression and genome studies in wheat and its relatives. In this project, we first anchored the ph1b deletion on 5BL by wheat 90K SNP assay, and then delimited the deletion to a genomic region of 60,014,523 bp by chromosome walking. The nucleotide positions of both distal and proximal breakpoints (DB and PB) were identified for the ph1b deletion. This will facilitate understanding of the genetic and molecular mechanism underlying the Ph1 activity in wheat. Meanwhile, we have developed user-friendly molecular markers specific for the ph1b deletion based on the DNA sequences of the genomic regions immediately proximal to PB and distal to DB. These new ph1b deletion-specific markers dramatically improves the efficacy of the ph1b mutant in alien gene introgression from wild grasses into wheat and homoeologous recombination-based genome studies in wheat and its relatives. In addition, these markers have been effectively used to assist selection in the transfer of the ph1b deletion from CS to the adapted US wheat genotypes in this project.

Publications

  • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Zhang, W., Zhang, M., Zhu, X., Cao, Y., Sun, Q., Ma, G. Chao, S., Yan, C., Xu, S., and Cai, X. 2017. Molecular cytogenetic and genomic analyses reveal new insights into the origin of the wheat B genome. Theor Appl Genet (Online First DOI 10.1007/s00122-017-3007-0 )
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Zhang, W., Cao, Y., Zhang,M., Zhu, X., Ren, S., Long, Y., Gyawali, Y., Chao, S., Xu, S., and Cai, X. 2017. Meiotic homoeologous recombination-based alien gene introgression in the genomics era of wheat. Crop Sci 57: 1189-1198.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Zhang, W., Zhang, M., Zhu, X., Cao, Y., Ren, S., Long, Y., Gyawali, Y., Chao, S., Xu, S.S., and Cai, X. 2017. Alien Gene Introgression in the Genomics Era of Wheat (poster). Plant & Animal Genome XXV, San Diego, CA, January 14-18, 2017.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Zhang, W., Zhang, M., Cao, Y., Zhu, X., Ren, S., Long, Y., Gyawali, Y., Chao, S., Xu, S.S., and Cai, X. 2017. Enriching and understanding the wheat B genome by meiotic homoeologous recombination. Joint Conference of the National Association of Plant Breeders Annual Meeting and the USDA/NIFA Annual PD Workshop, UC at Davis, CA, August 7-10,2017.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Somo, M., Pirseyedi, S.-M., Cai, X., and Marais, F. 2017. Modified versions of the Lr62 translocation of wheat. Crop Sci. 57: 18981905.
  • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Boehm, J. D., Zhang, M., Cai, X., and Morris, C. F. 2017. Molecular and cytogenetic and molecular characterization of the 5DS-5BS chromosome translocation conditioning soft kernel in durum wheat. Plant Genome (doi:10.3835/plantgenome2017.04.0031)
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Curwen-McAdams, C., Arterburn, M., Murphy, K., Cai, X., and Jones, S.S. 2017. Toward a taxonomic definition of perennial wheat: A new species �Tritipyrum aaseae described. Genetic Resources and Crop Evolution 64: 16511659.
  • Type: Book Chapters Status: Published Year Published: 2016 Citation: Xu, S. S., Liu, Z., Zhang, Q., Niu, Z., Jan, C. C., Cai, X. 2016. Chromosome painting by GISH and multi-color FISH. Methods Mol. Biol. 1429: 7-21.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Liu, Z., Seiler, G. J., Gulya, T.J., Feng, J., Rashid, K. Y., Cai, X., Jan, C. C. 2017. Triploid production from interspecific crosses of two diploid perennial Helianthus with cultivated sunflower. G3 (Genes, Genomes, Genetics) 7: 1097-1108.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Qi, L. L., Foley, M. E., Cai, X., and Gulya, T. J. 2016. Genetics and mapping of a novel downy mildew resistance gene,Pl18, introgressed from wild Helianthus argophyllus into cultivated sunflower (Helianthus annuus L.). Theor Appl Genet 129: 741-752.


Progress 11/01/15 to 10/31/16

Outputs
Target Audience:Onegraduate student and one postdoctoral researcher have participated in this research project. They have received extensive training in molecular cytogenetics, genomics,and high-throughput genotyping technology. In addition, they have learned new technologies we have developed in chromosome engineering and genome manipulation and characterization in this project. Also, we will bring the results and discoveries we have obtained in this project into the graduate cytogenetics class (PLSC 741) to help students understand how the genomics technologies and resources benefit cytogenetic studies on chromosome variation and engineering. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Onepostdoctoral research scientist,one graduate student, three undergraduate students, and one research specialist (technician) have participated in this research project. They have received extensive training in molecular cytogenetic and high-throughput genotyping technologies from PI, co-PI, and collaborators.Some of the resultsobtained inthis project may be presented in the Plant and Animal Genome conference in San Diego, CA January 2017. How have the results been disseminated to communities of interest?Research results and strategies of this projectwill bepresented in the international scientific conference (Plant and Animal Genome XXIII conference) and to the commodity groups, such as ND Wheat Commission, to help wheat growers understand the significance and impact of this research on wheat production. Also, we have used some of the research materials and results in the genetics classes to enhance students understanding of chromosome engineering and its application in crop improvement. What do you plan to do during the next reporting period to accomplish the goals?We have made significant progress toward the research goals in the first year of the project. In the next year, we will continue making efforts toward the research goals in the following areas: 1. Continue making crosses/backcrosses to recover US wheat genetic backgrounds and retain ph1b deletion in the introgresion materials using molecular markers; 2. Analyze DNA sequences flanking the ph1b deletion and develop PCR-based molecular markers for chromosome walking; 3. Perform chromosome walking toapproach the deletion points; 4. Develop PCR-based molecular markers immediately flanking the ph1b deletion; 5. Train the postdoctoral research fellow and graduate students; 6. Publish and present research results.

Impacts
What was accomplished under these goals? Wheat has a large number of wild grass relatives with unique genes that wheat generally does not have. They represent an invaluable gene pool for wheat improvement. However, it is difficult to use this gene pool directly in wheat breeding for variety development because of the genetic differences of the wild grasses from wheat. Pre-breeding efforts are needed to make the wild grass genes usable for wheat variety development. The most feasible pre-breeding approach for that is to incorporate the genes of interest from wild grasses into wheat using the genetic system called ph1b mutant that enhances gene exchange between wild grasses and wheat. But the ph1b genetic system is available only in the old spring wheat landrace 'Chinese Spring' (CS) with poor agronomic performance. This has limited the utility of this genetic system in gene transfer from wild grasses into wheat. In this project, we have been introducing the ph1b system into the major classes of US wheats from CS. This will bridge the gene flow from wild grasses directly into US wheats and expand the genetic basis of US wheats. Molecular markers are the useful genetic tools for the characterization and utilization of the genes targeted in wheat breeding and germplasm development. They have been widely used to assist selection of specific genes in wheat breeding and various wheat genetic studies. Here we are developing ph1b mutant-specific molecular markers to assist selection of ph1b mutant in pre-breeding and germplasm development in this project. Those molecular markers will improve the efficacy of the ph1b system in the gene transfer from wild grasses to wheat and facilitate utilization of the wild grass gene pool in wheat improvement. Following are the detailed accomplishments under each of the research objectives in the first year of this project. Objective 1: Incorporate CS ph1b mutant into US wheats for homoeologous recombination-based gene introgression (HRBGI) One to two varieties under each of the five major wheat classes were obtained from different US wheat production regions, including the soft red winter wheat 'SS 8641' (GA) and 'Pembroke 14 (KY), soft white winter wheat 'Otto' (WA) and 'Jasper' (WA), hard white spring wheat 'Argent' (ND), hard red spring wheat 'Alsen' (ND), and durum wheat 'Divide' (ND). We crossed these US wheat varieties to CS ph1b mutant and the resultant F1 hybrids were self-pollinated to produce homozygous ph1b mutant for backcrossing with the respective US wheat parents. We have selected F2 individuals homozygous for ph1b mutant from the crosses involving Alsen and Divide using molecular markers and crossed the homozygotes back to Alsen and divide, respectively. Selection of the ph1b homozygotes from the F2 populations of other crosses and subsequent backcrosses are in progress. In addition, we have been transferring ph1b mutant to a bread wheat line (Line E) that is universally susceptible to all stem rust races. Wild relatives of wheat represent an invaluable gene pool for wheat improvement. Many of the stem rust resistance genes in wheat are derived from wheat-related wild grasses. Incorporating ph1b mutant into this wheat line will facilitate genetic and pathological studies of newly identified stem rust resistance genes from wild grasses. Also, this will enhance utilization of the new resistance genes in wheat breeding and germplasm development. Objective 2: Develop ph1b mutant-specific molecular markers to improve the efficacy of the mutant in HRBGI Molecular markers are available to tag the wild type allele Ph1, but not for the ph1b mutant allele (deletion). In this project, we have been developing ph1b mutant-specific molecular markers by taking advantage of the genomics technologies and resources currently available in wheat. First, we genotyped CS (Ph1Ph1) and CS ph1b mutant (ph1bph1b) using wheat 90K SNP arrays. Comparative analysis of the SNP genotyping data identified the genomic region that spans the ph1b deletion on the long arm of chromosome 5B (5BL). The SNP loci flanking the deletion have been detected according to the consensus SNP linkage map of wheat chromosome 5B. We have developed PCR-based markers using the contextual and nearby DNA sequences of the SNPs located inside as well as outside of the deletion. These PCR-based markers have been used to verify and demarcate the deletion region on 5BL. In addition, we have performed DNA sequence analysis of the deletion and nearby genomic regions to identify the deletion points for marker development. Current results indicate that we have been approaching the deletion points through this chromosome walking strategy. This will lead us toward the development of ph1b mutant-specific molecular markers.

Publications

  • Type: Journal Articles Status: Submitted Year Published: 2016 Citation: Zhang, W., Cao, Y., Zhang,M., Zhu, X., Ren, S., Long, Y., Gyawali, Y., Chao, S., Xu, S., and Cai, X. 2016. Meiotic homoeologous recombination-based alien gene introgression in the genomics era of wheat. Crop Sci (submitted)
  • Type: Journal Articles Status: Submitted Year Published: 2016 Citation: Zhang, W., Zhang, M., Zhu, X., Cao, Y., Sun, Q., Ma, G., Chao, S., Xu, S., Yan, C., and Cai, X. 2016. The footprint of Aegilops speltoides in the B genome of wheat. Proc. Natl. Acad. Sci. USA (submitted)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Cao, Y., Zhang, M., Zhang, W., Zhu, X., Ren, S., Chao, S., Xu, S.S., and Cai, X. 2016. Enriching and understanding the wheat Genome by inducing homoeologous meiotic recombination (poster). Plant & Animal Genome XXIV, San Diego, CA, January 9-13, 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gill, B.K., Niu, Z., Klindworth, D.L., Chao, S., Friesen, T.L., Jin, Y., Rouse, M.N., Cai, X., Zhang, Q., and Xu, S.S. 2016. Introgression of a new Ug99-resistant gene from Thinopyrum junceum into wheat (poster). Plant & Animal Genome XXIV, San Diego, CA, January 9-13, 2016.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Zhu, X., Zhong, S., and Cai., X. 2016. Effects of D-genome chromosomes and their A/B-genome homoeologs on Fusarium head blight resistance in durum wheat. Crop Sci 56:1049-1058.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Zhu, X., Zhong, S., Chao, S., Gu, Y., Kianian, S., Elias, E., and Cai, X. 2016. Toward a better understanding of the genomic region harboring Fusarium head blight resistance QTL Qfhs.ndsu-3AS in durum wheat. Theor Appl Genet 129:31-43.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Somo, M., Pirseyedi, S.-M., Cai, X., Poudel, R., Chao, S., and Marais, F. 2016. Mapping of Lr56 translocation recombinants in wheat. Plant Breed 135: 413-419.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Pirseyedi, S.-M., Somo, M., Poudel, R., Cai,X., McCallum, B., Saville, B., Fetch, T., Chao, S., and Marais, F. 2015. Characterization of recombinants of the Aegilops peregrina-derived Lr59 translocation of common wheat. Theor Appl Genet 128: 2403-2414.
  • Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Curwen-McAdams, C., Arterburn, M., Murphy, K., Cai, X., and Jones, S.S. 2016. Toward a taxonomic definition of perennial wheat: A new species �Tritipyrum aaseae described. Genetic Resources and Crop Evolution (in press)