Study On The Influence Of Rice Stripe Virus Infection On Chloroplast And Its Proteins

Rice stripe virus(RSV)is one of the most damaging rice pathogens,causing dramatic losses in rice production in East Asia.Chlorosis is the general symptom in RSV-infected plants,while it is still not very clear on how RSV infection caused chlorosis.On rice,the local yellow stripe on leaves caused by RSV infection is followed closely by the necrosis.Hence,rice leaves is not very suitable to explore this mechanism.The Nicotiana benthamiana plants infected by RSV showed the symptoms of unanimous chlorosis.Studies have shown that the the chlorosis symptom caused by RSV infection is associated with chloroplast abnormality.In the present,we found that the ultrastructure of chloroplasts from RSV-infected O.sativa and N.benthamiana leaves is abnormal.Moreover,the chloroplast membrane complexes were down-regulated in RSV-infected leaves in Blue Native PAGE analysis.These results indicate that the chlorosis symptom caused by RSV infection is probably related to the chloroplast abnormality.We next explored the process of RSV infection leading to abnormal chloroplast.Proteomics have been applied to identify a number of chloroplast proteins that are differentially expressed after virus infection.But few studies have been used to identify the proteins whose location is changed.These proteins may also be involved in the process of virus infection causing chloroplast abnormality.We here used protoplast-chloroplast proteomics to obtain 66 nucleus-encoded chloroplast proteins which expressed in the protoplast but did not transport to chloroplasts after RSV infection.GO enrichment analysis of these 66 candidate proteins showed that protein targeting to the chloroplast and its associated multiple biological pathways were enriched in the "biological process" category.And these three candidate proteins involved in the regulation of the biological pathway of protein targeting to the chloroplast,which were named as regulatory factor.It verified that the location of the candidate proteins were abnormal and indicated that RSV might affect the multiple chloroplast proteins and the multiple biological pathways related to chloroplast protein localization,resulting in abnormal chloroplast.Besides,GO enrichment analysis of the 41 candidate proteins with chloroplast transit peptide structure,found that these same three regulatory factors involved in the regulation of the biological pathway of protein targeting to the chloroplast.In addition,these three regulatory factors had the chloroplast transport peptide structure.It indicated that these three regulatory factor,K4CSN4,K4CR23 and K4BXN9,might regulate the biological pathway of protein targeting to the chloroplast by locating on the chloroplast.