Mutations in a subfamily of abscisic acid receptor genes promote rice growth and productivity.

Abstract

Abscisic acid (ABA) is a key phytohormone that controls plant growth and stress responses. It is sensed by the pyrabactin resistance 1 (PYR1)/PYR1-like (PYL)/regulatory components of the ABA receptor (RCAR) family of proteins. Here, we utilized CRISPR/Cas9 technology to edit group I (<i>PYL1</i>-<i>PYL6</i> and <i>PYL12</i>) and group II (<i>PYL7</i>-<i>PYL11</i> and <i>PYL13</i>) <i>PYL</i> genes in rice. Characterization of the combinatorial mutants suggested that genes in group I have more important roles in stomatal movement, seed dormancy, and growth regulation than those in group II. Among all of the single <i>pyl</i> mutants, only <i>pyl1</i> and <i>pyl12</i> exhibited significant defects in seed dormancy. Interestingly, high-order group I mutants, but not any group II mutants, displayed enhanced growth. Among group I mutants, <i>pyl1/4/6</i> exhibited the best growth and improved grain productivity in natural paddy field conditions, while maintaining nearly normal seed dormancy. Our results suggest that a subfamily of rice <i>PYLs</i> has evolved to have particularly important roles in regulating plant growth and reveal a genetic strategy to improve rice productivity.