Molecular Identification Of Pre-harvest Sprounting Related Genes Qphs.sicau.3B.1 And TaAbI4 In Wheat

Pre-harvest sprouting(PHS)can degrade both yield and quality,which lead to severe economic loss worldwide.The main inner factor to the PHS is seed dormancy,and plant hormones,such as Abscisic acid(ABA)playing important role in regulating seed dormancy and germination.In this study,we tried to research on the mechanism of PHS and seed dormancy in two different ways,the one is from phenotype to gene(forward way)and the other is gene to phenotype(reverse way): a major PHS resistant QTL had been found with a recombination inbred lines(RILs)population derived from PHS susceptible cultivar‘Lang' and PHS resistant Spelta wheat ‘CSCR6'.Two SCAR markers were developed to track the QTL for marker assisted selection(MAS).And then,we had constructed ABA signal related pathway in wheat.Based on gene expression level,key genes,such as Ta ABI4 had been selected for molecular identification and e QTL mapping with the use of RILs population derived from CM32(PHS susceptible)and SHW-L1(PHS resistant).The main results of the study are as follows:1)A major QTL related to PHS resistant Qphs.sicau.3B.1 had been found,which could explain 14.5%-14.9% phenotypic avariation,and closely linked to the DAr T marker w Pt-6187.Two SCAR markers,named as Ph3 B.1 and Ph3 B.2 were developed.Ph3 B.1could amplify a 400 bp band in the lines with the same allele of ‘CSCR6',while Ph3 B.2could only amplify a 1000 bp band in 'Lang' allele,respectively.The two SCAR markers could be used for marker assisted selection(MAS).2)We introgressed Qphs.sicau.3B.1 into the durum wheat ‘Bellaroi',with the use of Ph3 B.1,Ph3 B.2,and phenotype data,we finally identified five tetraploid lines with resistance to PHS,which could be used for durum qulity breeding.3)Comparing with 297 ABA signal related genes and their information about expression in Arabidopsis,rice and wheat,we found that the number of gnes encoding regulating proteins(especially transcriptional factors and protein enzyme related genes)were more than genes encoding structure proteins.Based on RNA-seq data from different organs,development stages in wheat,member genes from the same family were expressed in the similar tissues.And 12 universal seed specific expressed genes were found in three species.4)With the ABA signal related genes interaction network in Arabidopsis,we constructed the co-expression network of ABA signal related genes in wheat with hierarchy analysis.With the result,we found that interactions in wheat was much complex than that in Arabidopsis,and the ABA pathway could be classfied into 4 tiers.The first one was the core proteins in ABA pathway,including ABA receptors,protein enzymes Sn RK2 and PP2C;the second tier was about key TFs could be regulated by core proteins of ABA pathway.Some of the seed dormancy related key genes also included.The third tier was about the effetors which regulated by TFs,and most of genes in this tier were structure protein related genes.And the forth one consisted genes related to protein modification.For example,genes related to protein phosphorylation,acetylation,oxidation and so on.5)Some genes like Ta ABI4,Ta KEG and so on were found with opposite expression patterns in wheat compared with Arabidopsis via RT-PCR,wth the use of RILs population CM32/SHW-L1,we had found two e QTL in wheat,the one was located on chromosome 2B,with the physical length of 1.8Mb,which main contributed from CM32,the other one was located on chromosome 7A,with the e QTL length was about108 Mb,and the comprehensive factor was negative to the expression level of ABI4.Finally,10 candidate genes had been found which might be associated with regulating Ta ABI4 expression.