Identification and Expression Profiling of the Auxin Response Factors in Capsicum annuum L. under Abiotic Stress and Hormone Treatments

Abstract

Auxin response factors (ARFs) play important roles in regulating plant growth and development and response to environmental stress. An exhaustive analysis of the <i>CaARF</i> family was performed using the latest publicly available genome for pepper (<i>Capsicum annuum</i> L.). In total, 22 non-redundant <i>CaARF</i> gene family members in six classes were analyzed, including chromosome locations, gene structures, conserved motifs of proteins, phylogenetic relationships and Subcellular localization. Phylogenetic analysis of the ARFs from pepper (<i>Capsicum annuum</i> L.), tomato (<i>Solanum lycopersicum</i> L.), <i>Arabidopsis</i> and rice (<i>Oryza sativa</i> L.) revealed both similarity and divergence between the four ARF families, and aided in predicting biological functions of the CaARFs. Furthermore, expression profiling of <i>CaARF</i>s was obtained in various organs and tissues using quantitative real-time RT-PCR (qRT-PCR). Expression analysis of these genes was also conducted with various hormones and abiotic treatments using qRT-PCR. Most <i>CaARF</i> genes were regulated by exogenous hormone treatments at the transcriptional level, and many <i>CaARF</i> genes were altered by abiotic stress. Systematic analysis of <i>CaARF</i> genes is imperative to elucidate the roles of <i>CaARF</i> family members in mediating auxin signaling in the adaptation of pepper to a challenging environment.