QTL Mapping Of Leaf Senescence Traits After Blocking Maize Pollination

Source:sink ratio has close relationship with leaf senescence rate.The QTLs associating with pollination-prevention on leaf senescence has never been found yet in maize.To learn more about genetic mechanism of pollination-prevention on leaf senescence,recombinant inbred line(RIL population)derived from B73 × Mo17 was used to mapping the QTLs responsible for the phenotype.142 lines which have consistent pollination-prevention leaf senescence rate of 2 years were chosen and combined with corresponding genotype data to map target QTLs.Five QTL,including one major QTL and four minor QTL were identified.To confirm this result,the lines showed most significant phenotype were selected for bulk analysis.The RNA-seq data was used to physical map the genome regions,which were significantly associated with pollination-prevention leaf senescence rate.A 4.47 Mb genomic region on chromosome 8 was highly associated with the target trait,and overlapped with the major QTL identified using IBM(Intermated B73×Mo17)genetic map.There are 81 genes harbored in this zone.We speculated 7 of them may associate with leaf senescence rate after pollination-prevention.Based on the B73 and Mo17 transcriptome data of silking,1 week after silking,and 2 weeks after silking,a gene co-expression network was constructed.UDPGlucose pyrophosphorylase gene(AC197705.4＿FGT011)was involved in the module that highly associated with sugar metabolisation,and co-expressed with glutamine synthetase 1 gene,the key gene in nitrogen remobilization.Thus AC197705.4＿FGT011 was most likely to be the target gene.This study paved the way for detecting genes and responding mechanisms involved in regulating pollination-prevention on leaf senescence.