Abstract
The seed germination has been shown to require ROS. However, little is known about the molecular mechanism how ROS promote seed germination. Here, we report that ROS promotes seed germination by increasing the expression of GA biosynthesis genes. O{SUB}2{/SUB}{SUP}-{/SUP} was immediately generated following seed imbibition. DNA microarray analysis and seed germination test showed GA biosynthesis genes were upregulated by H{SUB}2{/SUB}O{SUB}2{/SUB} treatment that promoted seed germination. The effect of H{SUB}2{/SUB}O{SUB}2{/SUB} treatment was observed only at an early period of seed germination. DPI slightly inhibited generation of O{SUB}2{/SUB}{SUP}-{/SUP} with decrease in the expression level of GA biosynthesis genes. Unexpectedly, a mutant of NADPH oxidase show that increased generation of O{SUB}2{/SUB}{SUP}-{/SUP} promoted with seed germination and expression of GA biosynthesis genes. These results suggest that during seed germination O{SUB}2{/SUB}{SUP}-{/SUP} or H{SUB}2{/SUB}O{SUB}2{/SUB} is an early signal inducing GA biosynthesis genes, and that NADPH oxidase is a component of O{SUB}2{/SUB}{SUP}-{/SUP} generation following seed imbibiiton.
