Identification Of Loci For Waterlogging Tolerance Of Maize

Waterlogging is one important factor of abiotic stress which affects maize（Zea mays L.） growth. Previous studies have shown that the resistant to waterlogging of maize is a complex quantitative trait that controlled by several minor genes.It has been carried out a lot of research for maize about waterlogging of genetic, physiological and molecular mechanisms all over the world. But those studies that research of direct reaction of maize waterlogging tolerance, target traits of breeding selection and genetic study were not deep enough. In this study, we used 170 recombination inbred lines and 368 inbred lines analysis leaf injury of maize after waterlogging by linkage analysis and association analysis respectively to identify major QTLs and combine previous studies in our laboratory, to predict candidate genes of waterlogging tolerance in maize. The main research results are as follows:1. Analysis 368 different sources of maize inbred lines for Multi- point test, CML298、CML411、CML415、CIMBL12、B11、JIAO51 and CI7 in 23 inbred lines which were strong waterlogging tolerance were identited. These inbred lines can as desirable allele donor for genetic improvement of maize waterlogging tolerance.2. The use of 368 inbred lines genome of about 0.5millon SNPs and flooded maize leaf injury after waterlogging identified 53 SNPs significantly associated with leaf injury by genome-wide association study. These SNPs on chr2, chr3, chr4, chr8, chr9 and chr10 respectively, and detected 93 genes on downstream and upstream 50 kb range of the significantly association SNPs. Most of these genes invoved in stress or cellular processes or regulate cellular processes.3. 5 QTLs, q LI3, q LI6, q LI8-1,q LI8-2 and q LI9, identified by linkage analys were localized on Chr3, Chr6, Chr8, Chr9, could explained phenotypic variance in the range of 5%--22%. And compared with the results of previous studies, q LI3 and q LI8-1, q LI8-2 consistent with the results of previous study.4. The combination of linkage and association analysis show that chr6.S₇1234661, chr8.S₁52748478, chr8.S₁52747857, chr8.S₁52748415, chr9.S₁00612608 and chr9.S₁09314092, six significantly associated SNPs are located q LI6, q LI8-2 and q LI9 interval. A total of 16 genes in 50 kb range upstream and downstream of the six significantly assocated SNPs. We predicted GRMZM2G095302, GRMZM2G095333 and GRMZM2G395672 as candidate genes for maize waterlogging tolerance by functional annotation and research; We identified expression of GRMZM2G095302 and GRMZM2G395672 have correation with waterlogging tolerance base on the result of q RT-PCR in waterlogging-resistant properties significantly different inbred lines, so, GRMZM2G095302 and GRMZM2G395672 can as key genes to study.