ONAC066, A Stress-Responsive NAC Transcription Activator, Positively Contributes to Rice Immunity Against Through Modulating Expression of and Three Cytochrome P450 Genes.

NAC transcriptional factors constitute a large family in rice and some of them have been demonstrated to play crucial roles in rice immunity. The present study investigated the function and mechanism of in rice immunity. ONAC066 shows transcription activator activity that depends on its C-terminal region in rice cells. -OE plants exhibited enhanced resistance while -Ri and plants showed attenuated resistance to . A total of 81 genes were found to be up-regulated in -OE plants, and 26 of them were predicted to be induced by . Four genes, including and , were up-regulated in -OE plants but down-regulated in -Ri plants. ONAC066 bound to NAC core-binding site in promoter and activated expression, indicating that is a ONAC066 target. A set of cytochrome P450 genes were found to be co-expressed with and 5 of them were up-regulated in -OE plants but down-regulated in -Ri plants. ONAC066 bound to promoters of cytochrome P450 genes , , and and activated their transcription, indicating that these three cytochrome P450 genes are ONAC066 targets. These results suggest that ONAC066, as a transcription activator, positively contributes to rice immunity through modulating the expression of and a set of cytochrome P450 genes to activate defense response.