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Yeast two-hybrid assay was used to screen the rice cDNA library using Rice stripe virus (RSV) NS2 protein as a bait.A novel rice protein interacting with RSV NS2 was obtained,which was homologous to Arabidopsis thaliana SGS3 (AtSGS3) protein and was designated as OsSGS3.The full-length OsSGS3 gene was amplified by RT-PCR and cloned into yeast expression vector pGADT7.Yeast two-hybrid assay indicated that NS2 could interact with full-length OsSGS3.OsSGS3 possessed the three domains typical of AtSGS3: zinc finger, XS and coiled coil.Three OsSGS3 deletion mutants: OsSGS3-1, which contained the znic finger domain, OsSGS3-2, which contained the XS domain, and OsSGS3-3, which contained the coiled coil domain were constructed.Yeast two-hybrid assay indicated that NS2 could interact with full-length OsSGS3, OsSGS3-1, OsSGS3-2 and OsSGS3-3.Cellular localization studies indicated that OsSGS3-YFP accumulated in cytoplasmic foci that perfectly resembled those of AtSGS3 and NS2-CFP accumulated in cell wall and nuclei in Nicotiana benthamiana leaves.We confirmed the interaction between OsSGS3 and NS2 by using co-IP, BiFC, and colocalization.The results of colocalization revealed that a considerable proportion of OsSGS3 was redistributed to nucleus by NS2.We speculated that the redistribution of OsSGS3 by NS2 might disrupt the normal function of OsSGS3.AtSGS3 has been demonstrated to be involved in small RNA production.To explore the possible biological implications of the interaction of RSV NS2 with OsSGS3, we first detected the expression patterns of 5 auxin responsive factors (ARFs) that had been domonstrated to be potential targets of trans acting siRNAs.The results indicated that the overall accumulation levels of the 5 genes increased in RSV infected rice.