Association Analysis Revealed That TaPYL4 Genes Are Linked to Plant Growth Related Traits in Multiple Environment

Yinghong Xue,Ruilian Jing,Xi Yang,Xinguo Mao,Xiaoping Chang,Long Li,Chaonan Li,Jingyi Wang,Chenyang Hao,Runzhi Li

doi:10.3389/fpls.2021.641087

Abstract

Abscisic acid (ABA), one of phytohormones, plays an important regulatory role in plant growth and development. ABA receptor PYL4 (pyrabactin resistance 1-like 4) was previously detected to be involved in plant response to a variety of stresses. TaPYL4 overexpression could enhance wheat (Triticum aestivum) drought resistance. In order to further investigate TaPYL4’s role in regulating development of other major agronomic traits in wheat, genes of TaPYL4-2A, TaPYL4-2B, and TaPYL4-2D were cloned from wheat, respectively. Polymorphism analysis on TaPYL4 sequences revealed that encoding regions of the three genes were highly conserved, without any SNP (single nucleotide polymorphism) presence. However, nine SNPs and four SNPs were identified in the promoter regions of TaPYL4-2A and TaPYL4-2B, respectively. Functional molecular markers were developed based on these polymorphisms, which were then used to scan a natural population of 323 common wheat accessions for correlation analysis between genotype and the target phenotypic traits. Both TaPYL4-2A and TaPYL4-2B markers were significantly correlated with plant growth-related traits under multiple environments (well-watered, drought and heat stress treatments). The additive effects of TaPYL4-2A and TaPYL4-2B were verified by the combinational haplotype (Hap-AB1∼Hap-AB4) effects determined from field data. Cis-acting elements were analyzed in the promoters of TaPYL4-2A and TaPYL4-2B, showing that a TGA-element bound by ARFs (auxin response factors) existed only in Hap-2A-1 of TaPYL4-2A. Gene expression assays indicated that TaPYL4-2A was constitutively expressed in various tissues, with higher expression in Hap-2A-1 genotypes than in Hap-2A-2 materials. Notably, TaARF4 could act as TaPYL4-2A transcription activator in Hap-2A-1 materials, but not in Hap-2A-2 genotypes. Analysis of geographic distribution and temporal frequency of haplotypes indicated that Hap-AB1 was positively selected in wheat breeding in China. Therefore, TaPYL4-2A and TaPYL4-2B could be a valuable target gene in wheat genetic improvement to develop the ideal plant architecture.

Highlights

Wheat (Triticum aestivum) is one of the most important food crops in the world, and the main grain crop in China
According to the SNPs in TaPYL4-2A (Figure 1A) and TaPYL4-2B (Figure 2A) promoter regions, two haplotypes were identified for TaPYL4-2A (Hap2A-1 and Hap-2A-2) and TaPYL4-2B (Hap-2B-1 and Hap-2B2), respectively
We found that TaPYL4-2A and TaPYL42B contributed to the growth-related traits such as spike length (SL), peduncle length (PLE) and plant height (PH) in wheat

Summary

Introduction

Wheat (Triticum aestivum) is one of the most important food crops in the world, and the main grain crop in China. Enhancement of wheat yield plays an important role in ensuring world food security. To increase wheat grain yield, gene mining and innovation of germplasm with superior agronomic traits are always the key research fields in wheat breeding. During the "Green Revolution" of 1960s, the discovery of semi-dwarf genes led to a dramatic increase in wheat yields (Peng et al, 1999; Saville et al, 2012). Combined with previous findings, exploiting the excellent genetic resources of wheat is the most economical and effective way to breed new varieties with higher grain yields

Methods

Results

Conclusion