Small RNAs mediated host antiviral defense in rice
Y. LI (1) (1) Peking University, China

Rice is the most important stable food supply worldwide. RNAi, the evolutionarily conserved mechanism of antiviral defense which is well studied in plants and other eukaryotes, is poorly understood in economically important crops. Rice encodes 19 AGOs, AGO18 is a member of a novel clade of AGOs from rice. We found that AGO18 is highly induced by infections of evolutionary different viruses. Loss-of-function ago18 mutation abolishes, whereas over-expression of AGO18 increases antiviral activity. Significantly, AGO18 functions antiviral defense through disturbing and sequestering certain miRNAs such as miR168 and miR528 and releasing their targets which are directly involved in antiviral defense. Expression of miR168 resistant AGO1a in ago18 background or mutated miR528 rescues or increases rice antiviral activity. AGO18 enhances rice antiviral defense through a novel mechanism in which AGO18 positively regulates miR168 target AGO1 for antiviral immunity. We also found that AGO18 was loaded with a large amount of miR528, which suggests that miR528 may also play important regulatory roles in rice defense response to virus. Our current research focuses on how miR528 function in antiviral defense mechanism(s).

Abstract Number: C17-1
Session Type: Concurrent