Function Of NbSRRP1 In Turnip Mosaic Virus Infection

Turnip mosaic virus(TuMV)is one of the most harmful vegetable viruses in the world,causing great economic losses to global vegetable production.S1 RNA binding ribosomal protein 1(SRRP1)is a nucleic acid binding protein in the nucleic acid-binding proteins superfamily.In N.benthamiana,NbSRRP1 has been shown to affect the splicing and processing of chloroplast transcripts;harbor RNA chaperone activity affecting the splicing and processing of chloroplast transcripts and play a role in Arabidopsis seedling growth in the presence of ABA.But its function in the process of virus infection is unclear.Results showed that NbSRRP1 could respond to the infection of TuMV.The amount of NbSRRP1 transcript was down-regulated after TuMV was inoculated into N.benthamiana.The GFP-fused NbSRRP1 localization experiment shows that NbSRRP1 is mainly localized in chloroplasts.TRV-mediated silencing of NbSRRP1 led to yellowing of systemic leaves,and TuMV was more susceptible to infection in this silenced plant than in the control plant.After NbSRRP1 in N.benthamiana was silenced,the m RNA level of the key autophagic gene NbBeclin1 was down-regulated.Furthermore,the interaction between NbSRRP1 and NbBeclin1 was identified and verified by Yeast two hybrid(Y2H)and bimolecular fluorescence complementation(Bi FC)assays.And the two S1 domains of the NbSRRP1 are key regions for interaction between NbSRRP1 and NbBeclin1.The m RNA level of NbBeclin1 was up-regulated when it co-expressed with NbSRRP1.The protein accumulation of NbBeclin1 was significantly higher when it co-expression with NbSRRP1.We observed by laser confocal microscopy while transient over-expression of NbSRRP1 can activate autophagy.Transient over-expression of NbBeclin1 can also activate autophagy,and transient co-expression of NbSRRP1 and NbBeclin1 can further enhance the occurrence of autophagy.In summary,our study identified that NbSRRP1 may negatively regulates TuMV infection through interaction with NbBeclin1.