Molecular Genetic Architecture Of Internode Elongation Related Traits In Response To Ethephon In Maize

The study were performed in 2014 to 2015 in different ecological region of maize,the objectives of the study were:dissection of the molecular genetic architecture of internodes elongation-related traits in response to ethylene by linkage analysis and association analysis in maize.The main results were as follows:1.Ethephon significantly decreased plant height,ear height,leaf length,leaf width,and leaf sheath in inbred lines of temperate maize.The sensitive index here were ear height>leaf length>plant height>leaf sheath>leaf width.Plant architecture related traits in response to ethylene was not affected by the directional selection of evolution in maize.Based on principal component analysis,we build a comprehensive evaluation model of for plant architecture-related traits in response to ethephon in maize,F=0.102ZXi+0.098ZX2-0.051ZX3-0.009ZX4+0.116ZX5+0.582ZX6-0.861ZX7-0.615ZX8+2.861ZX9-1.712 ZX10,which can be used to distinguish the inbred lines sensitive of ethephon responses in internodes elongation of temperate maize plants.2.In association population,three environment were detected 61-182 SNPs at the whole genome level significantly(P<2.0× 10-4),respectively.Bioinformatics analysis found that 80 candidate genes were significantly related to target traits,involving multiple synthesis and signal transduction of plant hormones.That indicated internodes elongation-related traits in response to ethephon in maize by many minor genes together,and the SNP and candidate gene detection in multiple environments,has an important reference value for elucidate the underlying molecular mechanisms of ethephon responses in internodes elongation of maize plants.3.In RIL population,104 QTLs associated with intemodes elongation-related traits were identified under the two treatment conditions by composition-interval mapping.An individual QTL explained 3.87 to 14.91%of the phenotypic variance.QTL qB-ET_PH6a-wq for PH in the interval between PZE-106020696 and PZE-106013766 on chromosome 6,and QTL qB-ET_PH9a-ls for PH in the interval between PZE-109026651 and PZE-109061750 on chromosome 9,were identified for up to two traits in both locations under both treatments,explained 10.99,13.03%of the phenotypic variance,respectively.These consistent and stable regions are important QTLs of potential hot spots for PH,ear height(EH),and internode length above the uppermost ear(ILAU)response to ethephon in maize;these results will be valuable for elucidate the underlying molecular mechanisms of ethephon responses in maize.4.AP2/ERF transcription factor family involved in plant hormone crosstalk of stress signal.Using maize inbred lines Zheng58,Chang72,KUI3,and B77,APETALA2/Ethylene-Responsive Element Binding Factor ZmEATB were isolated and cloned successfully using reverse transcription PCR.The full-length cDNA sequence was 950 bp,include 801bp complete ORF region,which encode a 267 amino acid peptides,ZmEATB belongs to ERF subfamily can be identified by a typical GCC box.A BLAST of sequence analysis revealed that ZmEATB showed multiple differences of amino acid sequence on inbred lines Zheng58,Chang72,B77,respectively.qRT-PCR showed that the expression of ZmEATB gene was higher in Zheng58,and B77 than Chang 72,and KUI3.The difference of amino acid of ZmEATB and expression patterns was mainly due to the inbred lines sensitive of ethephon responses in internodes elongation of maize plants.