Comprehensive Atlas of Wheat (Triticum aestivum L.)AUXIN RESPONSE FACTORExpression During Male Reproductive Development and Abiotic Stress

AUXIN RESPONSE FACTOR (ARF) proteins regulate a wide range of signaling pathways, from general plant growth to abiotic stress responses. Here, we performed a genome-wide survey in wheat (Triticum aestivum) and identified 69TaARFmembers that formed 24 homoeologous groups. Phylogenetic analysis clusteredTaARFgenes into three clades, similar toARFgenes inArabidopsis(Arabidopsis thaliana) and rice (Oryza sativa). Structural characterization suggested thatARFgene structure and domain composition are well conserved between plant species. Expression profiling revealed diverse patterns ofTaARFtranscript levels across a range of developmental stages, tissues, and abiotic stresses. A number ofTaARFgenes shared similar expression patterns and were preferentially expressed in anthers. Moreover, our systematic analysis identi?ed three anther-specificTaARFgenes (TaARF8,TaARF9, andTaARF21) whose expression was signi?cantly altered by low temperature in thermosensitive genic male-sterile (TGMS) wheat; theseTaARFgenes are candidates to participate in the cold-induced male sterility pathway, and offer potential applications in TGMS wheat breeding and hybrid seed production. Moreover, we identified putative functions for a set ofTaARFsinvolved in responses to abscisic acid and abiotic stress. Overall, this study characterized the wheatARFgene family and generated several hypotheses for future investigation of ARF function during anther development and abiotic stress.