Polymorphism And Functional Analysis Of Ethylene Response Factor Gene TaERF73 In Wheat

Wheat(Triticum aestivum L.)is major food crop in China,however,with the rapid increase of population and environmental change,wheat yield is facing serious threat.Research shows AP2/ERF(APETALA2/Ethylene responsive factor)superfamily play roles in plant development and abiotic stress responses.But the functions of TaERF73 genes in wheat is not yet been studied extensively.In this study,Hanxuan 10 was used as the material to clone wheat ethylene response factor TaERF73,and through a series of analyses,such as gene polymorphism analysis,basic characteristics analysis,rice transformation,and association analysis to reveal the gene function,and functional markers were developed to provide a theoretical basis for molecular marker-assisted breeding.The main results are as follows:1.Two genomic sequences of TaERF73,TaERF73-4A and TaERF73-4B,were cloned from wheat,and containing two exons and one intron.The genome sequence of TaERF73-4A is 1039 bp,and the genome sequence of TaERF73-4B is 1032 bp.2.The expression patterns of TaERF73 in different tissues at different stages were analyzed,and it was found that the expression level of TaERF73 was the highest in root tissues at seedling and jointing stages.3.The p CAMBIA1300-TaERF73-GFP recombinant vector was constructed and expressed in tobacco,and the results showed that TaERF73 is localized in the nucleus.4.The full length and the truncated sequence of TaERF73 were fused into the PGBKT7 vector to produce the corresponding fusion protein and transformed into yeast.It was found that the TaERF73 full length has transactivation activity,and C-terminal outside AP2/ERF domain is responsible for the transactivation activity of TaERF73.5.Promoter analysis showed that there were multiple stress-responsive cis-acting elements in the TaERF73 promoter region,such as Auxin response element,Me JA response element,ABA response element ABRE,drought-induced MYB binding site and low temperature response element and so on.To elucidate the responses to various plant hormones and stresses,expression levels of TaERF73 in roots under plant hormones and abiotic stresses treatments were tested by q RT-PCR,The results shows TaERF73 was regulated by NAA,Me JA,ABA,PEG and low temperature indicating its role in plant hormone signaling and abiotic stress response.6.To investigate the functions of TaERF73,ectopic expression of TaERF73 in rice suggested that overexpression TaERF73 significantly reduced root length than wild type,and indicating TaERF73 negatively regulates root growth.7.We detected the sequence polymorphisms of TaERF73 in the 32 accessions with high polymorphisms.Four SNPs were found in the coding region of TaERF73-4B,while no SNP in TaERF73-4A;According to TaERF73-4B gene polymorphism,dCAPS-119 molecular marker was developed;TaERF73-4B is significantly associated with plant height(PH),peduncle length(PL),penultimate internode length(LPI)and thousand-grain weight(TGW)in 323 population.Hap-4B-2 is a favourable haplotype owning deeper roots,shorter plant height and higher thousand-grain weight;The frequency of Hap-4B-2 increased significantly from landscapes to modern cultivars in the ten major wheat regions of China demonstrated that Hap-4B-2has been experienced positive selection in the breeding history.Therefore,the favourable haplotype and functional marker of TaERF73-4B developed in this study are of great value in marker assisted breeding.