OsCYP71D8L as a key regulator involved in growth and stress response by mediating gibberellins and cytokinins homeostasis in rice

Abstract

Phytohormones are pivotal in the regulation of plant growth and development, and acclimation to adverse environments. Multiple cytochrome P450 monooxygenases (CYP450s) are involved in the biosynthesis and catabolism of phytohormones. Here, we reported that a CYP450 member of CYP71 clan, OsCYP71D8L, participated in the control of multiple agronomic traits and abiotic stress responses by affecting gibberellin (GA) and cytokinin (CK) homeostasis in rice. We found that its gain-of-function mutant (cyp71d8l) and transgenic plants overexpressing OsCYP71D8L (OsCYP71D8L-OE) displayed similar phenotypes such as dwarfed plant, reduced panicle length and grain number per panicle. In OsCYP71D8L-OE seedlings, endogenous GAs and CKs was notably decreased and increased as compared with wild type (WT), respectively. Correspondingly, the dwarfed plant and less developed root of cyp71d8l and OsCYP71D8L-OE seedlings could be rescued by exogenous GA3, but more exacerbated by exogenous 6-BA. Importantly, cyp71d8l and OsCYP71D8L-OE seedlings maintained high chlorophyll contents and low reactive oxygen species level, and showed significantly enhanced tolerances to drought and high salt compared with WT. Thus, our results suggest that OsCYP71D8L plays roles in regulating rice growth and stress responses by coordinating GAs and CKs homeostasis, and it is useful to engineer stress-tolerant rice.