Molecular cytogenetic characterization of a novel wheat–Psathyrostachys huashanica Keng T3DS-5NsL•5NsS and T5DL-3DS•3DL dual translocation line with powdery mildew resistance

Authors: LI, JIACHUANG - Northwest A&f University; ZHAO, LI - Northwest A&f University; CHENG, XUENI - Northwest A&f University; Bai, Guihua; LI, MAO - Northwest A&f University; WU, JUN - Northwest A&f University; YANG, QUNHUI - Northwest A&f University; CHEN, XINHONG - Northwest A&f University; YANG, ZUJUN - University Of Electronic Science And Technology Of China; ZHAO, JIXIN - Northwest A&f University

Submitted to: BMC Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/26/2020
Publication Date: 4/15/2020
Citation: Li, J., Zhao, L., Cheng, X., Bai, G., Li, M., Wu, J., Yang, Q., Chen, X., Yang, Z., Zhao, J. 2020. Molecular cytogenetic characterization of a novel wheat–Psathyrostachys huashanica Keng T3DS-5NsL•5NsS and T5DL-3DS•3DL dual translocation line with powdery mildew resistance. Biomed Central (BMC) Plant Biology. 20:163. https://doi.org/10.1186/s12870-020-02366-8.
DOI: https://doi.org/10.1186/s12870-020-02366-8

Interpretive Summary: Psathyrostachys huashanica is a wild wheat relative with valuable traits that can be used to improve wheat productivity. We developed a wheat line named TR77 that carries a P. huashanica chromosome segment (5Ns) on chromosome 3D. Cytogenetic and molecular analyses showed that this alien segment was first translocated to chromosome 5D and then translocated again from chromosome 5D to 3D of wheat. TR77 is a novel stable wheat–P. huashanica dual translocation line and showed longer spikes, more kernels per spike, and much better powdery mildew resistance than its wheat parents. Thus, it is a useful germplasm line for breeding improved disease resistance.

Technical Abstract: Psathyrostachys huashanica Keng (2n = 2x = 14, NsNs) carries many outstanding agronomic traits, therefore is a valuable resource for wheat genetic improvement. Wheat–P. huashanica translocation lines are important intermediate materials for wheat breeding and studying the functions of alien chromosomes. However, powdery mildew resistance in these translocation lines has not been reported previously. This study developed a novel wheat–P. huashanica translocation line TR77 by selecting a F7 progeny from the cross between heptaploid hybrid H8911 (2n = 7x = 49, AABBDDNs) and durum wheat line Trs-372. Chromosome karyotype of 2n = 42 = 21II was observed in both mitotic and meiotic stages of TR77. Genomic in situ hybridization analysis identified two translocated chromosomes that paired normally at meiosis stage in TR77. Molecular marker analysis showed that part of chromosome 5D was replaced by part of alien chromosome fragment 5Ns. It meant replacement made part 5DL and part 5NsL·5NsS existed in wheat background, and then translocation happened between these chromosomes and wheat 3D chromosome. Fluorescence in situ hybridization demonstrated that TR77 carries dual translocations: T3DS-5NsL·5NsS and T5DL-3DS·3DL. Analysis using a 15K-wheat-SNP chip confirmed that SNP genotypes on the 5D chromosome of TR77 matched well with these of P. huashanica, but poorly with common wheat line 7182. The translocation was physically located between 202.3 and 213.1 Mb in 5D. TR77 showed longer spikes, more kernels per spike, and much better powdery mildew resistance than its wheat parents: common wheat line 7182 and durum wheat line Trs-372. TR77 is a novel stable wheat–P. huashanica T3DS-5NsL·5NsS and T5DL-3DS·3DL dual translocation line and showed significant improved spike traits and resistance to powdery mildew compared to its parents, thus, it can be an useful germplasm for breeding disease resistance and studying the genetic mechanism of dual translocations.