Involvement of C4 Protein of Beet Severe Curly Top Virus (Family Geminiviridae) in Virus Movement |
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| Authors: | Kunling Teng Hao Chen Jianbin Lai Zhonghui Zhang Yuanyuan Fang Ran Xia Xueping Zhou Huishan Guo Qi Xie |
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| Affiliation: | 1. State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.; 2. State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.; 3. State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China.;University of Heidelberg, Germany |
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| Abstract: | BackgroundBeet severe curly top virus (BSCTV) is a leafhopper transmitted geminivirus with a monopartite genome. C4 proteins encoded by geminivirus play an important role in virus/plant interaction.Methods and FindingsTo understand the function of C4 encoded by BSCTV, two BSCTV mutants were constructed by introducing termination codons in ORF C4 without affecting the amino acids encoded by overlapping ORF Rep. BSCTV mutants containing disrupted ORF C4 retained the ability to replicate in Arabidopsis protoplasts and in the agro-inoculated leaf discs of N. benthamiana, suggesting C4 is not required for virus DNA replication. However, both mutants did not accumulate viral DNA in newly emerged leaves of inoculated N. benthamiana and Arabidopsis, and the inoculated plants were asymptomatic. We also showed that C4 expression in plant could help C4 deficient BSCTV mutants to move systemically. C4 was localized in the cytosol and the nucleus in both Arabidopsis protoplasts and N. benthamiana leaves and the protein appeared to bind viral DNA and ds/ssDNA nonspecifically, displaying novel DNA binding properties.ConclusionsOur results suggest that C4 protein in BSCTV is involved in symptom production and may facilitate virus movement instead of virus replication. |
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