A novel thiol-reductase activity of Arabidopsis YUC6 confers drought tolerance independently of auxin biosynthesis

• DOI: 10.1038/ncomms9041
• Publication Date: 2015-08-28T09:44:59Z
• Authors: Joon-Yung Cha; Woe-Yeon Kim; Sun Bin Kang; Jeong Im Kim; Dongwon Baek; In Jung Jung; Mi Ri Kim; Ning Li; Hyun-Jin Kim; Masatoshi Nakajima; Tadao Asami; Jamal S. M. Sabir; Hyeong Cheol Park; Sang Yeol Lee; Hans J. Bohnert; Ray A. Bressan; Jose M. Pardo; Dae-Jin Yun
• Keywords: 2. Zero hunger; 0303 health sciences; Indoleacetic Acids; Arabidopsis Proteins; Arabidopsis; 15. Life on land; Biochemistry; Adaptation, Physiological; Article; 6. Clean water; Droughts; Mixed Function Oxygenases; Biological sciences; Oxidative Stress; 03 medical and health sciences; Phenotype; Gene Expression Regulation, Plant; Stress, Physiological; Mutation; Sulfhydryl Compounds; Plant sciences; Oxidoreductases; Reactive Oxygen Species

Abstract YUCCA (YUC) proteins constitute a family of flavin monooxygenases (FMOs), with an important role in auxin (IAA) biosynthesis. Here we report that Arabidopsis plants overexpressing YUC6 display enhanced IAA-related phenotypes and exhibit improved drought stress tolerance, low rate water loss controlled ROS accumulation under oxidative stresses. Co-overexpression IAA-conjugating enzyme reduces IAA levels but tolerance is unaffected, indicating the stress-related phenotype not based on overproduction. contains previously unrecognized FAD- NADPH-dependent thiol-reductase activity (TR) overlaps FMO domain involved Mutation conserved cysteine residue (Cys-85) preserves suppresses TR whereas mutating NADPH-binding sites, are common to domains, abolishes all outputs. We provide paradigm for single protein playing dual role, regulating plant development conveying defence responses.