A Torreya grandis ARF transcription factor TgARF15 enhances drought stress tolerance

Auxin response factors (ARFs) are central components of the growth hormone signaling pathway, responsible for regulating the expression of corresponding growth hormone genes. To date, ARFs have demonstrated diverse functions and roles, with identification in various species, including Arabidopsis thaliana and Oryza sativa . However, their specific functions in Torreya grandis , an evergreen and economically significant tree species primarily found in China, remain elusive. In this study, we identified 15 ARF genes ( TgARF1 - TgARF15 ) in T. grandis and observed their distribution across 11 chromosomes. We analyzed the expression patterns of TgARFs in various tissues and their responses to drought stress. Our findings revealed a significant reduction of TgARF15 expression in leaf tissues under drought conditions, implying a potential key role for TgARF15 in drought stress resistance. Additionally, we determined that TgARF15 was localized in the nucleus. Furthermore, overexpression of TgARF15 in Arabidopsis resulted in enhanced drought resistance, attributed to increased enzymatic activity of antioxidant enzymes. Moreover, we identified a direct interaction between TgARF15 and TgIAA1, both in vivo and in yeast. These findings will facilitate future efforts in establishing a foundation for in-depth exploration of their specific mechanisms related to drought resistance, and addressing challenges in the T. grandis industry.