Genetic mapping of Stb19, a new resistance gene to Zymoseptoria tritici in wheat
A new and dominant R gene Stb19 is identified from a soft wheat cultivar ‘Lorikeet’ and was mapped on the distal region of chromosome 1DS. Two tightly linked KASP markers were also discovered and validated for molecular-assisted breeding programs.
A new R gene, designated as Stb19, provides resistance to Zymoseptoria tritici in wheat. This new dominant gene resides on the short arm of chromosome 1D, exhibiting complete resistance to three Z. tritici isolates, WAI332, WAI251, and WAI161, at the seedling stage. A genetic linkage map, based on an F2:3 population of ‘Lorikeet’ and ‘Summit,’ found the Stb19 gene at a 9.3 cM region on 1DS, closely linked with two Kompetitive Allele-Specific PCR markers, snp_4909967 and snp_1218021. Further, the two markers were tested and validated in another F2:3 population and 266 different wheat accessions, which gave over 95% accuracy of resistance/susceptibility prediction. Combined with the physical location of the identified SNPs and the previous evidence of gene order on chromosome 1DS (centromere–Sr45–Sr33–Lr21–telomere), Stb19 is proposed to be located between Sr33 and Lr21. Thus, the newly discovered Stb19 along with the KASP markers represents an increase in genetic resources available for wheat breeding resistance to Z. tritici.
The authors thank the staff from Wagga Wagga Agricultural Institute, Wagga Wagga. Thanks to Dr. Andrzej Kilian from DArT Pty Ltd on the comments and explanations of genetic analysis. This study was conducted as a co-investment from NSW Department of Primary Industries, The Australian National University and the Grain Research and Development Corporation, under project DAN00203 as part of the Grains, Agronomy, and Pathology Partnership.
Author contribution statement
AM and NY conceived of the study and coordinated its design and execution. NY conducted the experiments and analyzed the data. NY, MCM, PSS, and AM wrote the manuscript. All authors read and approved the final manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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