Host-Induced Gene Silencing of Effector AGLIP1 Enhanced Resistance of Rice to Rhizoctonia solani AG1-IA

Rice sheath blight, caused by Rhizoctonia solani AG1-IA, is a major disease in rice-growing areas worldwide. The effectors of phytopathogenic fungi play an important role during the infection process of fungal pathogens onto their host plants. However, the molecular mechanisms by which R. solani effectors regulate rice immunity are poorly understood. Through prediction, 78 candidate effector molecules were identified. Using the tobacco rattle virus-host induced gene silencing system, 45 RNAi constructs of effector genes were infiltrated into Nicotiana benthamiana leaves. The results revealed that eight of these constructs resulted in a significant reduction in necrosis caused by the infection of the AG1-IA strain GD-118. Additionally, stable rice transformants carrying the double-stranded RNA construct for one of the effector genes, AGLIP1, were generated to further verify the function of this gene. The suppression of the AGLIP1 gene increased the resistance of both N. benthamiana and rice against GD-118, and also affected the growth rate of GD-118, indicating that AGLIP1 is the key pathogenic factor. Small RNA sequencing showed that the host-induced gene silencing (HIGS) vectors were processed into siRNAs within the plants and then translocated to the fungi, leading to the silencing of the target genes. As a result, AGLIP1 might be a good candidate for HIGS, thereby boosting crop resistance against the pathogen and helping the limitation of R. solani infection.