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Spatio‐temporal expression of patatin‐like lipid acyl hydrolases and accumulation of jasmonates in elicitor‐treated tobacco leaves are not affected by endogenous levels of salicylic acid
Author(s) -
Dhondt Sandrine,
Gouzerh Guillaume,
Müller Axel,
Legrand Michel,
Heitz Thierry
Publication year - 2002
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 - 10.1046/j.1365-313x.2002.01465.x
Subject(s) - jasmonic acid , elicitor , salicylic acid , methyl jasmonate , biochemistry , jasmonate , hypersensitive response , arachidonic acid , endogeny , reactive oxygen species , botrytis cinerea , plant defense against herbivory , chemistry , fatty acid , biology , enzyme , programmed cell death , arabidopsis , botany , gene , mutant , apoptosis
Summary We have previously isolated three tobacco genes ( NtPat ) encoding patatin‐like proteins, getting rapidly induced during the hypersensitive response (HR) to tobacco mosaic virus, in advance to jasmonate accumulation. NtPAT enzymes are lipid acyl hydrolases that display high phospholipase A 2 (PLA 2 ) activity and may mobilize fatty acid precursors of oxylipins. Here, we performed a detailed study of NtPat gene regulation under various biotic and abiotic stresses. PLA 2 activity was poorly induced in response to drought, wounding, reactive oxygen intermediates, salicylic acid (SA) or methyl‐jasmonate (MJ) whereas the ethylene (ET) precursor, 1‐aminocyclopropane‐1‐carboxylic acid (ACC), provoked a moderate induction. In contrast, PLA 2 activity was strongly induced when ACC was combined with MJ, and in response to the bacterium Erwinia carotovora or to the fungus Botrytis cinerea , as well as to treatment with β‐megaspermin, a cell death‐inducing protein elicitor. A simplified system based on the infiltration of β‐megaspermin into leaves was used to dissect the spatio‐temporal activation of PLA 2 activity with regards to the accumulation of jasmonates and to the influence of endogenous SA. NtPat ‐encoded PLA 2 activity was rapidly induced in the infiltrated zone before the appearance of cell death and with some delay in the surrounding living cells. A massive accumulation of 12‐oxo‐phytodienoic and jasmonic acids occurred in the elicitor‐infiltrated zone, but only low levels were detectable outside this area. A similar picture was found in SA‐deficient plants, showing that in tobacco, accumulation of jasmonates is not affected by the concomitant HR‐induced build‐up of endogenous SA. Finally, ET‐insensitive plants showed a weakened induction of PLA 2 activity outside the elicitor‐infiltrated tissue.