Meta-QTL analysis of tan spot resistance in wheat

Authors: LIU, YUAN - NORTH DAKOTA STATE UNIVERSITY; SALSMAN, EVAN - NORTH DAKOTA STATE UNIVERSITY; WANG, RUNHAO - NORTH DAKOTA STATE UNIVERSITY; GALAGEDARA, NELOMIE - NORTH DAKOTA STATE UNIVERSITY; ZHANG, QIJUN - NORTH DAKOTA STATE UNIVERSITY; Fiedler, Jason; LIU, ZHAOHUI - NORTH DAKOTA STATE UNIVERSITY; Xu, Steven; Faris, Justin; LI, XUEHUI - NORTH DAKOTA STATE UNIVERSITY

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2020
Publication Date: 5/20/2020
Citation: Liu, Y., Salsman, E., Wang, R., Galagedara, N., Zhang, Q., Fiedler, J.D., Liu, Z., Xu, S.S., Faris, J.D., Li, X. 2020. Meta-QTL analysis of tan spot resistance in wheat. Theoretical and Applied Genetics. 133:2363-2375. https://doi.org/10.1007/s00122-020-03604-1.
DOI: https://doi.org/10.1007/s00122-020-03604-1

Interpretive Summary: Tan spot is a major foliar disease worldwide in both bread and durum wheat and can reduce grain yield due to a reduction in photosynthetic capacity. Developing and growing resistant cultivars is a cost-effective and environmentally friendly approach to mitigate negative effects of the disease. Understanding the genetic basis of tan spot resistance can enhance the development of resistant cultivars. To do this we performed a meta-analysis to combine the results of 14 previously reported studies that had identified a total of 104 individual tan-spot resistance chromosomal regions. We discovered that these regions could be clustered together into 19 meta-locations and three of which had large genetic effects on multiple races of the pathogen. This information is important to plant breeders so they can focus energy on the most useful non-redundant gene regions for resistance and summarizes the existing information for pathologists looking to understand this disease better.

Technical Abstract: Tan spot, caused by a fungal pathogen Pyrenophora tritici-repentis (Ptr), is a major foliar disease worldwide in both bread wheat and durum wheat and can reduce grain yield due to reduction in photosynthetic area of leaves. Developing and growing resistant cultivars is a cost-effective and environmentally friendly approach to mitigate negative effect of the disease. Understanding the genetic basis of tan spot resistance can enhance the development of resistant cultivars. With that goal, over 100 QTL of resistance to tan spot induced by varied Ptr races and isolates have been identified from previous QTL mapping studies. Meta-QTL analysis can remove redundant QTL amongst various studies and target major QTL for marker-assisted selection in breeding application. In this study, we performed a meta-QTL analysis for tan spot resistance using the reported QTL from 14 previously QTL mapping studies. An integrated linkage map with a total length of 4,080.5 cM and containing 47,309 markers was assembled from 21 individual linkage maps and three previously published consensus maps. Nineteen meta-QTL were clustered from 104 initial QTL projected on the integrated map. Three of the 19 meta-QTL located on chromosomes 2A, 3B, and 5A, respectively, show large genetic effects and confer resistance to multiple races in multiple bread wheat and durum mapping populations. Integrating those race-nonspecific QTL is promising to provide high and stable resistance to tan spot in wheat.