Premium
NbEXPA1, an α‐expansin, is plasmodesmata‐specific and a novel host factor for potyviral infection
Author(s) -
Park SangHo,
Li Fangfang,
Renaud Justin,
Shen Wentao,
Li Yinzi,
Guo Lihua,
Cui Hongguang,
Sumarah Mark,
Wang Aiming
Publication year - 2017
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13723
Subject(s) - plasmodesma , expansin , host (biology) , biology , virology , host factors , cell , virus , genetics , gene , gene expression
Summary Plasmodesmata ( PD ), unique to the plant kingdom, are structurally complex microchannels that cross the cell wall to establish symplastic communication between neighbouring cells. Viral intercellular movement occurs through PD . To better understand the involvement of PD in viral infection, we conducted a quantitative proteomic study on the PD ‐enriched fraction from Nicotiana benthamiana leaves in response to infection by Turnip mosaic virus (Tu MV ). We report the identification of a total of 1070 PD protein candidates, of which 100 (≥2‐fold increase) and 48 (≥2‐fold reduction) are significantly differentially accumulated in the PD ‐enriched fraction, when compared with protein levels in the corresponding healthy control. Among the differentially accumulated PD protein candidates, we show that an α‐expansin designated Nb EXPA 1, a cell wall loosening protein, is PD ‐specific. Tu MV infection downregulates Nb EXPA 1 mRNA expression and protein accumulation. We further demonstrate that Nb EXPA 1 is recruited to the viral replication complex via the interaction with NI b, the only RNA ‐dependent RNA polymerase of Tu MV . Silencing of Nb EXPA 1 inhibits plant growth and Tu MV infection, whereas overexpression of Nb EXPA 1 promotes viral replication and intercellular movement. These data suggest that Nb EXPA 1 is a host factor for potyviral infection. This study not only generates a PD ‐proteome dataset that is useful in future studies to expound PD biology and PD ‐mediated virus–host interactions but also characterizes Nb EXPA 1 as the first PD ‐specific cell wall loosening protein and its essential role in potyviral infection.