Functional And Diversity Analysis Of TaERF5 In Wheat

Wheat is one of major grain food all over the world.The gradually growing population as well as changing climate is bringing big challenges for wheat production. New varieties with higher yield, better quality and more tolerance to bio/abio-stress are the only way to meet the human’s food need. Therefore, to discover the excellent genes or alleles will provide gene resources for wheat improvement.TaERF5 is a member of ERF transcription factor. We have investigated its diversity in the CDS and 5’UTR, but the SNPs over these regions were limited. Therefore, this study targeted to investigate its diversity based on haplotypes on UTRs. Associations of haplotypes with agronomical traits were carried out on natural population and introgression lines. Expression levels of Ta ERF5 in different tissues and different development period of young spikes were measured. Ta ERF5-B was overexpressed in rice variety Kitaake and wheat variety Fielder to confirm its function. The main results were as follows:1. By searching the current wheat sequences database, we obtained Ta ERF5-3’UTR sequences. About 1000 bp of Ta ERF5-3’UTR were sequenced for diploid, tetraploid and 18 hexaploid wheat lines and haplotypes were estimated according to sequencing data. Two SNPs were found in Ta ERF5-A-3’UTR and two haplotypes, named A-Hapl 1 and A-Hapl 2 were classified. Three SNPs were discovered in Ta ERF5-B-3’ UTR, and combined with the In Del in Ta ERF5-B-5’UTR, totally four haplotypes were identified for Ta ERF5-B(B-Hapl 1, B-Hapl 2, B-Hapl 3 and B-Hapl 4). Ta ERF5-D-3’UTR was monomorphic in hexaploid wheat. Functional markers for different haplotypes were developed and were used to genotype natural population(wild relatives, landraces and modern varieties) and introgression lines.2. Correlations of different haplotypes and agronomical traits were calculated by SPSS software. Ta ERF5-A was significantly related to jointing, heading and mature time. A-Hapl 1 was predominant haplotype and was fixed before wheat domestication. Nevertheless, A-Hapl 2 was associated with better traits, suggesting its potentiality in wheat improvement. Ta ERF5-B-Hapl 2 was both predominant and best haplotype in wheat evolution related to decreased plant height, heavier thousand grain weight and higher yield. Significant effect of B-Hapl 2 on yield also confirmed by introgression lines of Yanzhan 1.3. Gene expression levels of TaERF5-A, TaERF5-B and TaERF5-D in Chinese spring wheat seedling root, stem, stem node, leaf sheath, flag leaf, young spike were analyzed and found the three homeologous genes expressed in these tissues. Ta ERF5-A highly expressed in root, Ta ERF5-B highly expressed in flag leaf and young spike and Ta ERF5-D in leaf sheath. Furthermore, expression levels were analyzed in different development stages of spike of Yanzhan 1 and Fuzhuang30. In modern variety Yanzhan1, Ta ERF5-B demonstrated the highest expression level, while in Fuzhuang30, a variety bred in the 1950 s, the expression of Ta ERF5-D prevailed. The spike size, TGW and yield of Yanzhan1 are bigger than those of Fuzhuang30. The expression levels of homeologous Ta ERF5 in tissues need further analysis.