Development Of Markers For Wheat Stripe Rust Resistance Gene Yr26

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the wheat diseases worldwide. Development and utilization of resistant cultivars is the most economic, effective and environmentally-friendly way of controlling the disease. However, many cultivars with stripe rust resistance genes have become susceptible because of the rapid development of new PST(Puccinia striiformis f. sp. tritici) races. Molecular markers for marker-assisted breeding can speed up the development of resistant wheat cultivars in the pyramiding of resistance genes. It can increase the durability of resistance in breeding. Wheat (T. aestivum)-H. villosa 6VS/6AL translocation lines were highly resistant to stripe rust with resistance gene Yr26 located on chromosome IB. Development of markers for wheat stripe rust resistance gene Yr26 will play an important role in disease resistance breeding, fine mapping of genes and homo logy cloning.This research based on the research of Wang Chunmei, based on principles of comparative genomics, reference genome sequence of model plant Brachypodium. There are 90 bin-mapped wheat ESTs which are mapped to C-1BL-6-0.32. A total 60 of those ESTs can match to the region of 11.8-55.5 Mbp on the Bd3. They have very high colinearity. The STS markers were derived from ESTs on IB of wheat, had developed by Wang Chunmei. BLASTing these ESTs to the genome sequence of Brachypodium, BE497584 can match to the region of 29414494-29420453 bp on the Bd3, BF200811 can match to the region of 29973090-29961736 bp on the Bd3, BE426207 can match to the region of 31844075-31849869 bp on the Bd3. Thus, the first try can be focused on the 29.0 Mbp-41.0 Mbp region of the Brachypodium chromosome 3. Then we detect wheat ESTs (unigenes are used) which are mapped to the 29.0-41.0 Mbp region in Bd3. Then design the conserved primers to develop STS markers. Using unigenes as templates. If some ESTs primers did not show polymorphism, we develop CAPS markers by digestion PCR products with four base enzyme.In this research, isogenes lines which were derived from yangmai5/92R137//yangmai5 were analysed by AFLP, then transform the polymorphic fragments into SCAR markers.We screened a total of eight STS markers (244、307、366、388、415、507、38 and 631), three CAPS markers (C275、C433 and C523) and two AFLP-SCAR marker (A56 and A59), Dominant molecular markers include 244、307、388、415、507、631、C275、C433 and A56, codominant marker include 366、538、C523 and A59.Using 92R137//Yangmai 5 F2 population to detect these markers, the genetic distances range from 1.1-9.2 cM, especially 631with genetic distance of 1.1 cM.