Revealing the role of the gene against rice virus: from transformation to protein structure.

Rice virus (RHBV), transmitted by the insect vector , poses a significant threat to rice cultivation. Here, we use CRISPR/Cas9 technology to produce specific mutations in the gene of , using the Fedearroz 2000 variety, with the aim of elucidating the participation of the gene in resistance to RHBV. We obtained 14 edited plants that presented with deletions of one, two, and three nucleotides in the sequence of exon 23 of the gene. Phenotypic evaluations showed an increase in susceptibility to RHBV in the edited lines. We identified the presence of RHBV in the leaf tissue of infected plants by amplifying the nucleoprotein, , and genes of the virus. Using RT-qPCR, we analyzed the expression patterns of the gene, showing that in the edited lines, the expression profiles are similar to the susceptible control. Furthermore, modeling of the tertiary structure of the AGO4 protein and its mutant variant demonstrated changes in the PIWI domain and the presence of the DDH catalytic triad, confirming its role in mediating resistance to RHBV. Our study reveals the functional importance of the rice gene in RHBV resistance.