Powdery Mildew Resistant Germplasms Screening And Excellent Genes Discovery In Wheat (Triticum Aestivum L.) Of Henan Province

Wheat is the main source of food for about 1/3 population in the world.Powdery mildew(PM),one of the major diseases in wheat,seriously damages the yield and quality of wheat.Developing disease-resistant varieties is the most economical and effective control measure.At present,most of the disease resistance genes were identified at the seedling stage,and the gene mapping was basically achieved through the construction of biparental populations.In order to identify a batch of new wheat PM resistance genes and germplasms quickly,we genotyped 637 wheat core germplasms consisting of 371 landraces and 266 released cultivars in Henan Province using a wheat 660K microarray,and carried out multi-locus genome-wide association study(GWAS)based on the phenotypic data of wheat PM resistance at seedling stage in greenhouse and adult-plant stage in 2017-2020.The main results are as follows:1.Thirty-two resistant materils for PM at seedling stage in Henan province were screened,among which seven were highly resistant,including the landraces Baihulu,Duangancao,Baigeda(HXZ257),Bensiyuehuang and the released varieties Jimai 22,4B269,Zhengmai 883,and 25 medium resistant materils,including the landraces Tuhulutou,Jinguoyin,Liulinger,Helubai,Silengmai,Huisancao,Siyuecao,Youmangsaogudan and the released varieties Fulanni,Aifeng 3,Een 1,Zhengtaiyu 1,Yumai 47,Yumai 54,Zhongyu 5,Zhoumai 16,Zhoumai 17,Yumai 49-198,Zhoumai 22,Bainong 207,Zhongluotiegan,Zhengyumai 9987,Luomai 26,Bonong 6,Guomai 0319.Thirty-six resistant materils for PM at adult-plant stage in Henan province were screened,of which 21 were landraces:Tuhulutou,Sanyuehuang,Liulinger,Baihulu,Silengmai,Duangancao,Liekoucao,Kumai,Baimayidan,Foshoumai,Dongmai,Jiutouniao,Wuzitoumai,Jinsita,Baigeda,Huomai,Bensiyuehuang,Hongheshangtou,Hongyouzitou,Hongsuimai,Yuanzicao;Fifteen were released varieties:Zhengtaiyu 1,Yumai 51,Yumai 54,Zhongyu 5,Zhongyu 6,Xinmai 13,04Zhong 36,Zhongyu 12,Jimai 22,Zhongluotiegan,Yulong 1325,Zhengmai 1354,Zhengmai 883,Guomai 0319 and Zhengmai 119.Ten resistant materils for PM in whole growth period:Tuhulutou,Baihulu,Baigeda,Bensiyuehuang,Zhengtaiyu 1,Yumai 54,Zhongyu 5,Jimai 22,Zhengmai 883 and Guomai0319.These materials are all valuable germplasms for wheat PM resistance breeding.2.There were 34 significant single-nucleotide polymorphism(SNP)markers associated with wheat PM resistance at seedling stage,of which 11 markers could be repeatedly detected by different methods.SNP AX-108894618 on chromosome 6A,SNP AX-111554951 and SNP AX-89508859 on 7A,SNP AX-110956447 on 4B and SNP AX-108899176 on 2D were the same locus as SNP wsnp?Ex?c11621?18716254,Pm37,QPm.sfr-4B and Pm43 respectively.SNP AX-110071156 and SNP AX-94416898 on chromosome 7A,SNP AX-94473502 on 3B and SNP AX-109436089 on 1D are the new resistance loci for wheat PM.A total 100 SNP markers were detected significantly associated with adult plant resistance(APR)to PM in four field environments,11 of which could be detected in separated environments by different methods and also be significant in the best linear unbiased prediction(BLUP)values.Among these stable 11 SNP marks,SNP AX-110404341 on chromosome 2AL,SNP AX-111769070 on 5AL,SNP AX-110111855on 2BS and SNP AX-111134486 on 3BL are closely linked with Pm HNK54,QPm.nuls-5A,Pm42 and Pm HNK respectively.SNP AX-109052670 on 3BL was detected 12 times by five methods in four environments,named as QPm-3BL,which explained 0.00-12.98%of the total phenotypic variation.Two SNP markers AX-110117322 and AX-108771002 on1BL in the same linkage disequilibrium(LD)block were detected for two and six times in the four field environments,explaining 1.27-3.35%and 0.00-2.13%of the phenotypic variation,respectively.The two SNP markers were the same locus,named as QPm-1BL.There are only 8 and 5 materials resistant for QPm-3BL and QPm-1BL,and all of them are from landraces,which are rare and precious germplasms.3.SNP AX-109052670 near QPm-3BL was converted into a kompetitive allele-specific PCR(KASP)marker,which was verified in an F₂population consisting of155 individual plants constructed from the resistant material Baimayidan and susceptible parent Pumai 9.The marker can be used in molecular marker assisted selection(MAS)breeding.4.We combined gene functional annotation,KEGG pathway enrichment analysis,gene expression analysis,and comparative genomics analysis to identify the candidate gene PmBMYD for QPm-3BL,which can be used in wheat PM resistance breeding and molecular biology research.