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

Abscisic acid (ABA), one of phytohormones, plays an important regulatory role in plant growth and development. ABA receptor (pyrabactin resistance 1-like 4) was previously detected to be involved in plant response to a variety of stresses. overexpression could enhance wheat () drought resistance. In order to further investigate TaPYL4's role in regulating development of other major agronomic traits in wheat, genes of , , and were cloned from wheat, respectively. Polymorphism analysis on 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 and , 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 and markers were significantly correlated with plant growth-related traits under multiple environments (well-watered, drought and heat stress treatments). The additive effects of and were verified by the combinational haplotype (-AB1∼-AB4) effects determined from field data. -acting elements were analyzed in the promoters of and , showing that a TGA-element bound by ARFs (auxin response factors) existed only in -2A-1 of . Gene expression assays indicated that was constitutively expressed in various tissues, with higher expression in -2A-1 genotypes than in -2A-2 materials. Notably, TaARF4 could act as transcription activator in -2A-1 materials, but not in -2A-2 genotypes. Analysis of geographic distribution and temporal frequency of haplotypes indicated that -AB1 was positively selected in wheat breeding in China. Therefore, and could be a valuable target gene in wheat genetic improvement to develop the ideal plant architecture.