Development of Novel Wheat- 3S Translocations Conferring Powdery Mildew Resistance and Specific Molecular Markers for Chromosome 3S.

Powdery mildew of wheat, caused by f. sp. , is a destructive disease of common wheat. Cultivation of resistant varieties is the most cost-effective disease management strategy. Previous studies reported that chromosome 3S#2 present in Chinese Spring (CS)- 3S#2(3B) disomic substitution line TA3575 conferred resistance to powdery mildew. In this study, we further located the powdery mildew resistance gene(s) to the short arm of chromosome 3S#2 (3S#2S) by evaluating for f. sp. resistance of newly developed CS- 3S#2 translocation lines. Meanwhile, TA7545, a previously designated CS- 3S#3 disomic addition line, was reidentified as an isochromosome 3S#3S addition line and evaluated to confer resistance to powdery mildew, thus locating the resistance gene(s) to the short arm of chromosome 3S#3 (3S#3S). Based on transcriptome sequences of TA3575, 10 novel chromosome 3SS-specific markers were developed, of which 5 could be used to distinguish between 3S#2S and 3S#3S derived from accessions TL20 and TA1910 (TAM4) and the remaining 5 could identify both 3S#2S and 3S#3S. Also, CL897, one of five markers specific to both 3S#2S and 3S#3S, could be used to detect located at chromosome 3S#1S from accession TL01 in diverse wheat genetic backgrounds. The powdery mildew resistance genes on chromosomes 3S#2S and 3S#3S, the CS- 3S#2 translocation lines, and the 3SS-specific markers developed in this study will facilitate the transfer of f. sp. resistance genes into common wheat and provide new germplasm resources for powdery mildew resistance breeding.