FAD and NADPH binding sites of YUCCA6 are essential for chaperone activity and oxidative stress tolerance in Arabidopsis thaliana.

Phytohormone auxin plays a pivotal role in governing plant growth, development, and responses to abiotic stresses. YUCCA6 (YUC6), an auxin biosynthetic enzyme belonging to the flavin monooxygenase (FMO) subfamily, converts indole-3-pyruvic acid to indole-3-acetic acid. Our prior investigation uncovered that YUC6 also functions as a thiol-reductase and chaperone in a Cys85-dependent manner, resulting in conferred tolerance to nickel heavy metal stress and drought and delayed leaf senescence.