Premium
LePLDβ1 activation and relocalization in suspension‐cultured tomato cells treated with xylanase
Author(s) -
Bargmann Bastiaan O.R.,
Laxalt Ana M.,
Riet Bas ter,
Schouten Elske,
Van Leeuwen Wessel,
Dekker Henk L.,
De Koster Chris G.,
Haring Michel A.,
Munnik Teun
Publication year - 2006
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/j.1365-313x.2005.02631.x
Subject(s) - microbiology and biotechnology , xylanase , cytosol , phospholipase d , biology , secretion , subcellular localization , green fluorescent protein , biochemistry , plant cell , signal transduction , gene , enzyme , cytoplasm
Summary Phospholipase D (PLD) has been implicated in various cellular processes including membrane degradation, vesicular trafficking and signal transduction. Previously, we described a PLD gene family in tomato ( Lycopersicon esculentum ) and showed that expression of one of these genes, LePLD β 1 , was induced by treatment with the fungal elicitor xylanase. To further investigate the function of this PLD, a gene‐specific RNAi construct was used to knock down levels of LePLD β 1 transcript in suspension‐cultured tomato cells. Silenced cells exhibited a strong decrease in xylanase‐induced PLD activity and responded to xylanase treatment with a disproportionate oxidative burst. Furthermore, LePLD β 1 ‐silenced cell‐suspension cultures were found to have increased polyphenol oxidase activity, to secrete less of the β ‐ d ‐xylosidase LeXYL2 and to secrete and express more of the xyloglucan‐specific endoglucanase inhibitor protein XEGIP. Using an LePLD β 1–green fluorescent protein (GFP) fusion protein for confocal laser scanning microscopy‐mediated localization studies, untreated cells displayed a cytosolic localization, whereas treatment with xylanase induced relocalization to punctuate structures within the cytosol. Possible functions for PLD β in plant–pathogen interactions are discussed.