Open AccessA critical domain of Sweet potato chlorotic fleck virus nucleotide‐binding protein ( NaBp ) for RNA silencing suppression, nuclear localization and viral pathogenesis
Author(s) -
Deng XingGuang,
Peng XingJi,
Zhu Feng,
Chen YingJuan,
Zhu Tong,
Qin ShaoBo,
Xi DeHui,
Lin HongHui
Publication year - 2015
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.12186
Subject(s) - potato virus x , biology , nicotiana benthamiana , rna silencing , gene silencing , rna , nuclear localization sequence , microbiology and biotechnology , rna interference , virus , virology , gene , genetics
Summary RNA silencing is an important mechanism of antiviral defence in plants. To counteract this resistance mechanism, many viruses have evolved RNA silencing suppressors. In this study, we analysed five proteins encoded by Sweet potato chlorotic fleck virus ( SPCFV ) for their abilities to suppress RNA silencing using a green fluorescent protein ( GFP )‐based transient expression assay in N icotiana benthamiana line 16c plants. Our results showed that a putative nucleotide‐binding protein ( NaBp ), but not other proteins encoded by the virus, could efficiently suppress local and systemic RNA silencing induced by either sense or double‐stranded RNA ( dsRNA ) molecules. Deletion mutation analysis of NaBp demonstrated that the basic motif (an arginine‐rich region) was critical for its RNA silencing suppression activity. Using confocal laser scanning microscopy imaging of transfected protoplasts expressing NaBp fused to GFP , we showed that NaBp accumulated predominantly in the nucleus. Mutational analysis of NaBp demonstrated that the basic motif represented part of the nuclear localization signal. In addition, we demonstrated that the basic motif in NaBp was a pathogenicity determinant in the Potato virus X ( PVX ) heterogeneous system. Overall, our results demonstrate that the basic motif of SPCFV NaBp plays a critical role in RNA silencing suppression, nuclear localization and viral pathogenesis.