The Resistance Research Of Guinong775and The Development Of Gene-specific Marker And Application Of Pm21

Powdery mildew and stripe rust are two major diseases of wheat in the word andcountry’s food security are threated because of these. To select and extend resistant cultivarsare an economical effective and safe way. In this study, the resistant genes to stripe rust andpowdery mildew of Gguinong775was analyzed, results are as follows:1. The previous test results of our laboratory showed that Guinong775was controlled bya single dominant gene to CYR32, and the gene which is resistant to CYR32was located at1B chromosome, confirmed as Yr26. In my study, Gguinong775was found that it also carriesa single dominant gene for resistance to CH42and are different to Yr26.2. Pm21have broad-spectrum resistance to wheat powdery mildew. Based on thesequence of Stpk-V gene which was cloned and related to the resistance pathway, the proteinsequences were extracted and the conservative start-stop sites were analyzed by Pfamsoftware, in order to amplify this gene specifically, the marker WS-1was developed excludingconserved domain. For constructing an F2populations derived from susceptible cultivarAvocet S and the lines92R137carrying Pm21, infection types in F2plants were evaluated byartificial inoculation with isolate E09during seedling stage, F2plants were amplified by WS-1,and the testing results and infection types were analysed to confirm the accuracy of WS-1. Asa dominant molecular marker, WS-1could be amplified a949bp fragment in the lines withPm21on8%non-denaturing polyacrylamide gel, but did not in the lines without Pm21. The377F2populations segregated286resistant:91susceptible fitting the3:1ratio, whichindicated that Pm21presents a single dominant gene, and the testing results by WS-1wereconsistent with infection types. WS-1can be detected wheat cultivars and breeding lines whichcarry Pm21accurately, also can be applied to the gene pyramiding breeding in the future.3. A total of662wheat cultivars and breeding lines growing in different winter wheatregions in China were detected by WS-1to analyze the distribution of Pm21, and thematerials carrying Pm21were further tested the resistance to powdery mildew under fieldconditions. In order to further prove the accuracy of WS-1, the marker NAU/xibao15902developed by Cao Aizhong and others was used to amplify the lines with Pm21and withoutPm21(50samples from each type). There were49lines showed positive strand in662lines, and the average distribution frequency of Pm21gene was7.4%; the lines containing Pm21inSouthwestern Winter Wheat Region, Northern China Plain Winter Wheat Region, Yellow andHuai Valley Facultative Wheat Region and Middle&Lower Yangtze Valley Winter WheatRegion were33,4,9, and3, and their frequencies were34.4%,5.3%,3.1%and1.5%,respectively. The distribution of Pm21in winter wheat regions is different, the risk ofpathogen directional selection will be promoted because of the high frequency of Pm21genein wheat cultivars of Sichuan and Guizhou provinces, and we should pay more attention to itin wheat breeding.