Open AccessEndoplasmic reticulum stress responses function in the HRT‐mediated hypersensitive response in Nicotiana benthamiana
Author(s) -
Moon Ju Yeon,
Lee Jeong Hee,
Oh ChangSik,
Kang HongGu,
Park Jeong Mee
Publication year - 2016
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.12369
Subject(s) - nicotiana benthamiana , endoplasmic reticulum , biology , unfolded protein response , gene silencing , hypersensitive response , tunicamycin , gene , microbiology and biotechnology , gene expression , genetics , plant disease resistance
Summary HRT is a plant coiled‐coil, nucleotide‐binding and leucine‐rich repeat (CC‐NB‐LRR) disease resistance protein that triggers the hypersensitive response (HR) on recognition of Turnip crinkle virus (TCV) coat protein (CP). The molecular mechanism and significance of HR‐mediated cell death for TCV resistance have not been fully elucidated. To identify the genes involved in HRT/TCV CP‐mediated HR in Nicotiana benthamiana , we performed virus‐induced gene silencing (VIGS) of 459 expressed sequence tags (ESTs) of pathogen‐responsive Capsicum annuum genes. VIGS of CaBLP5 , which encodes an endoplasmic reticulum (ER)‐associated immunoglobulin‐binding protein (BiP), silenced NbBiP4 and NbBiP5 and significantly reduced HRT‐mediated HR. The induction of ER stress‐responsive genes and the accumulation of ER‐targeted BiPs in response to HRT‐mediated HR suggest that ER is involved in HR in N. benthamiana . BiP4/5 silencing significantly down‐regulated HRT at the mRNA and protein levels, and affected SGT1 and HSP90 expression. Co‐expression of TCV CP in BiP4/5 ‐silenced plants completely abolished HRT induction. Transient expression of TCV CP alone induced selected ER stress‐responsive gene transcripts only in Tobacco rattle virus (TRV)‐infected plants, and most of these genes were induced by HRT/TCV CP, except for bZIP60 , which was induced specifically in response to HRT/TCV CP. TCV CP‐mediated induction of ER stress‐responsive genes still occurred in BiP4/5 ‐silenced plants, but HRT/TCV CP‐mediated induction of these genes was defective. Tunicamycin, a chemical that inhibits protein N ‐glycosylation, inhibited HRT‐mediated HR, suggesting that ER has a role in HR regulation. These results indicate that BiP and ER, which modulate pattern recognition receptors in innate immunity, also regulate R protein‐mediated resistance.