AtPLAI Is an Acyl Hydrolase Involved in Basal Jasmonic Acid Production and Arabidopsis Resistance to Botrytis cinerea

Abstract

Intracellular phospholipase A2 (PLA2) plays an important role in regulating oxylipin biosynthesis in mammals, but the molecular and biochemical nature of intracellular PLA2 is not well understood in plants. Arabidopsis thaliana gene At1g61850 (AtPLAI) encodes a 140-kDa protein that is most similar to mammalian calcium-independent PLA2, and additionally contains leucine-rich repeats and Armadillo repeats. AtPLAI hydrolyzes phospholipids at both the sn-1 and sn-2 positions, but prefers galactolipids to phospholipids as substrates. Profiling of lipid species altered in response to the necrotrophic fungus Botrytis cinerea revealed decreases in the levels of phosphatidylglycerol and digalactosyldiacylglycerol, suggesting that hydrolysis of plastidic polar lipids might provide precursors for pathogen-induced jasmonic acid (JA) production. Disruption of AtPLAI by T-DNA insertion reduced the basal level of JA, but did not impede pathogen-induced production of JA, free linolenic acid, or hydrolysis of plastidic lipids. Still, AtPLAI-deficient plants exhibited more damage than wild type plants after B. cinerea infection, and pretreatment of plants with methyl jasmonate alleviated pathogen damage to the mutant plants. The study shows that AtPLAI is an acyl hydrolase, rather than a specific phospholipase A. AtPLAI is involved in basal JA production and Arabidopsis resistance to the necrotrophic fungus B. cinerea. Intracellular phospholipase A2 (PLA2) plays an important role in regulating oxylipin biosynthesis in mammals, but the molecular and biochemical nature of intracellular PLA2 is not well understood in plants. Arabidopsis thaliana gene At1g61850 (AtPLAI) encodes a 140-kDa protein that is most similar to mammalian calcium-independent PLA2, and additionally contains leucine-rich repeats and Armadillo repeats. AtPLAI hydrolyzes phospholipids at both the sn-1 and sn-2 positions, but prefers galactolipids to phospholipids as substrates. Profiling of lipid species altered in response to the necrotrophic fungus Botrytis cinerea revealed decreases in the levels of phosphatidylglycerol and digalactosyldiacylglycerol, suggesting that hydrolysis of plastidic polar lipids might provide precursors for pathogen-induced jasmonic acid (JA) production. Disruption of AtPLAI by T-DNA insertion reduced the basal level of JA, but did not impede pathogen-induced production of JA, free linolenic acid, or hydrolysis of plastidic lipids. Still, AtPLAI-deficient plants exhibited more damage than wild type plants after B. cinerea infection, and pretreatment of plants with methyl jasmonate alleviated pathogen damage to the mutant plants. The study shows that AtPLAI is an acyl hydrolase, rather than a specific phospholipase A. AtPLAI is involved in basal JA production and Arabidopsis resistance to the necrotrophic fungus B. cinerea. As a nonspecific necrotrophic pathogen, Botrytis cinerea infects more than 200 plant species (1Prins T.W. Tudzynski P. Von Tiedemann A.V. Tudzynski B. ten Have A. Hansen M.E. Tenberge K. van Kan J.A. Kronstad J.W. Fungal Pathology. Kluwer Academic Publishers, Doedrecht, Netherlands2000: 33-64Google Scholar). It obtains nutrients from dead host cells and attacks plants by producing cell wall-degrading enzymes, toxic reactive oxygen species, and host nonselective toxins, resulting in repression of host defense gene transcription, maceration of plant tissue, or host cell death (2Pieterse C.M. Schaller A. Mauch-Mani B. Conrath U. Tuzun S. Bent E. Multigenic and Induced Systemic Resistance in Plants. Springer Science+Business Media, New York2005: 166-198Google Scholar). Plants use both pre-existing and induced defense strategies to cope with pathogen infection (3Maleck K. Dietrich R.A. Trends Plant Sci. 1999; 4: 215-219Abstract Full Text Full Text PDF PubMed Scopus (200) Google Scholar). One important defense response is the production of oxylipins, which include a variety of oxygenated fatty acid-derived compounds (4Blee E. Trends Plant Sci. 2002; 7: 315-322Abstract Full Text Full Text PDF PubMed Scopus (478) Google Scholar, 5Howe G.A. Schilmiller A.L. Curr. Opin. Plant Biol. 2002; 5: 230-236Crossref PubMed Scopus (402) Google Scholar, 6Liechti R. Farmer E.E. Sci. STKE. 2006; 322: cm3Google Scholar). The best known oxylipins are jasmonic acid (JA) 2The abbreviations used are: JA, jasmonic acid; PLA, phospholipase A; LRR, leucine-rich repeats; GST, glutathione S-transferase; NBD, [12-(7-nitro-2–1,3-benzoxadiazol-4-yl)amino]-dodecanoyl; OPDA, oxophytodienoic acid; PA, phosphatidic acid; PC, phosphatidylcholine; PE, phosphatidylethanolamine; PG, phosphatidylglycerol; PI, phosphatidylinositol; PS, phosphatidylserine; MGDG, monogalactosyldiacylglycerol; DGDG, digalactosyldiacylglycerol; lyso-PC, lysophosphatidylcholine; lyso-PE, lysophosphatidylethanolamine; lyso-PG, lysophosphatidylglycerol; LOX, lipoxygenase; H2JA, dihydrojasmonic acid; MJT, carboxyl methyltransferase; OPR, 12-oxo-phytodienoic acid reductase; VSP2, vegetative storage protein; HPL, hydroperoxide lyase; AOS, allene oxide synthase; AOC, allene oxide cyclase; SA, salicylic acid; iPLA2, Ca2+-independent phospholipase A2; cPLA2, Ca2+-dependent phospholipase A2; WT, Wassilewskija ecotype; Arm, Armadillo. and its derivatives, collectively called jasmonates. Jasmonates induce changes in host defense responses, including increased expression of proteinase inhibitors, phenylalanine ammonia lyase, chalcone synthase, and proline-rich cell wall proteins (7Creelman R.A. Mullet J.E. Annu. Rev. Plant Physiol. Plant Mol. Biol. 1997; 48: 355-381Crossref PubMed Scopus (1514) Google Scholar, 8Farmer E.E. Ryan C.A. Proc. Natl. Acad. Sci. U. S. A. 1990; 87: 7713-7716Crossref PubMed Scopus (1127) Google Scholar, 9Farmer E.E. Ryan C.A. Plant Cell. 1992; 4: 129-134Crossref PubMed Google Scholar, 10Gundlach H. Muller M.J. Kutchan T.M. Zenk M.H. Proc. Natl. Acad. Sci. U. S. A. 1992; 89: 2389-2393Crossref PubMed Scopus (999) Google Scholar, 11Farmer E.E. Almeras E. Krishnamurthy V. Curr. Opin. Plant Biol. 2003; 6: 372-378Crossref PubMed Scopus (449) Google Scholar). JA plays a positive role in plant response to necrotrophic pathogen infection (12Thomma B.P. Eggermont K. Mauch-Mani B. R. B.P. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar). in the of oxylipin biosynthesis and its (4Blee E. Trends Plant Sci. 2002; 7: 315-322Abstract Full Text Full Text PDF PubMed Scopus (478) Google Scholar, 5Howe G.A. Schilmiller A.L. Curr. Opin. Plant Biol. 2002; 5: 230-236Crossref PubMed Scopus (402) Google Scholar, 6Liechti R. Farmer E.E. Sci. STKE. 2006; 322: cm3Google Scholar, M.J. Physiol. 1997; Google Scholar). acid, the most fatty acid in plant is the for JA the that linolenic acid for JA biosynthesis is not well is a of an linolenic acid is to from lipids by a as by phospholipase to that in (4Blee E. Trends Plant Sci. 2002; 7: 315-322Abstract Full Text Full Text PDF PubMed Scopus (478) Google Scholar, 5Howe G.A. Schilmiller A.L. Curr. Opin. Plant Biol. 2002; 5: 230-236Crossref PubMed Scopus (402) Google Scholar, 8Farmer E.E. Ryan C.A. Proc. Natl. Acad. Sci. U. S. A. 1990; 87: 7713-7716Crossref PubMed Scopus (1127) Google Scholar). a and JA biosynthesis but the is involved in and rather than in JA in vegetative S. A. K. Plant Cell. PubMed Scopus Google Scholar). The of and plastidic lipids oxylipins to that a plastidic lipids and that polar lipids the for a A. P. S. Biol. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, K. H. PubMed Scopus Google Scholar, C.M. P. S. R. Plant Physiol. 2006; PubMed Scopus Google Scholar). plant a role of in defense that free fatty and and in cells H. Plant Physiol. PubMed Google Scholar). The production of free fatty and is induced in as cell wall from fungus and cells of by and by S. Plant Sci. Scopus Google Scholar, S. Plant Physiol. PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, Ryan C.A. Plant Cell. 1999; PubMed Scopus Google Scholar, K. B. Plant Cell. 2002; PubMed Scopus Google Scholar, K. B. Plant Cell. 2006; PubMed Scopus Google Scholar). the gene and biochemical of the involved in JA production in defense response are not mammalian intracellular PLA2 plays a role in the of acid for the of oxylipins Cell. Full Text PDF PubMed Scopus Google Scholar, 2006; PubMed Scopus Google Scholar). Intracellular PLA2 of Ca2+-dependent PLA2 and Ca2+-independent PLA2 Arabidopsis to cPLA2, but plant with the of E. 2003; PubMed Scopus Google Scholar). The to a of storage proteins in proteins nonspecific acyl fatty acid from of including phospholipids and galactolipids B. PubMed Scopus Google Scholar). proteins are in plant species and in defense the expression of induced in cells with fungus B. or with a cell protein S. P. Plant PubMed Google Scholar, S. Muller A. Plant 2002; PubMed Scopus Google Scholar). acyl increased cell death and the of acid and JA, suggesting that proteins the production of JA and defense in S. P. Plant PubMed Google Scholar, S. Muller A. Plant 2002; PubMed Scopus Google Scholar). the expression of the gene to induced in response to and A. A. P. K. Plant Physiol. 2003; PubMed Scopus Google Scholar). of the gene increased plant to pathogen, that the rather than pathogen infection S. P. H. A. Plant PubMed Scopus Google Scholar). Arabidopsis with to S. P. H. A. Plant PubMed Scopus Google Scholar, A. S. H. Plant Physiol. 2002; PubMed Scopus Google Scholar). for a positive role for in the production of JA and in plant response to gene in AtPLAI A. S. H. Plant Physiol. 2002; PubMed Scopus Google encodes a protein with a but an more similar to mammalian than to Arabidopsis the proteins with to acid AtPLAI encodes a protein acid than contains leucine-rich repeats at its the and of that AtPLAI is an acyl that both phospholipids and galactolipids as that is involved in basal jasmonic acid and that Arabidopsis resistance to the necrotrophic fungus B. cinerea. Plant thaliana plants in a of and of The T-DNA insertion at gene AtPLAI acyl at the At1g61850 by T-DNA insertion to the of the Arabidopsis at the of S. Plant Physiol. PubMed Scopus Google Scholar). The and T-DNA at the and the of the The of T-DNA insertion by and the plants used in the of of the of AtPLAI and and by The the of the The resulting the of and the mutant plants as Bent A. Plant PubMed Google Scholar). The of JA in the plants and the pathogen with B. cinerea as of Plants with JA, and B. cinerea used for of plants. Fungal and as B.P. 1990; Google Scholar). a and with a of a of in plants at at in with a for the plants with a of and in salicylic acid or methyl jasmonate to with B. cinerea. plants with a and and of in from the Arabidopsis in The of the AtPLAI gene with the as a and of and The a and both The of AtPLAI with and the and of the after the glutathione The of the E. The cells to an of and induced with for at The of the protein as K. R. Biol. Full Text Full Text PDF PubMed Scopus Google and the protein with the PubMed Scopus Google Scholar). The of the protein by by at the sn-2 including and acid from the lipid in a and in by in a and used as and of protein to the in a of 200 The at for and by of and 200 of and by from the a the lipid in and a The in the The to free fatty and The lipid in the with and at and as a of and of in the a and the lipid in of by The as of the a the lipids the by to The to the lipid and by and and from Arabidopsis from Arabidopsis and as C.A. R. PubMed Scopus Google Scholar). the of the lipid a and or in by The and of protein in a of 200 The for at and by of and 200 of from the by in by to fatty acid and by of acid in and as an and at for fatty by of and of acid methyl an with and an the from the of from Plants and of plants with a and lipids after as C.A. R. PubMed Scopus Google Scholar). The lipids in by and used as a of the lipids and of AtPLAI to in a of 200 The for acyl as the of lipids and proteins and to the as the the lipids and the by the from plant a as S. Plant Cell. 1997; Google Scholar). of the a of and of with the of the Arabidopsis gene from gene used as The gene specific used for the are to AtPLAI allene oxide allene oxide allene oxide hydroperoxide 12-oxo-phytodienoic acid jasmonic acid carboxyl with a to the of JA and of Arabidopsis in of in the to and of with by for at by for and at for The used for JA and linolenic acid acid and acid used as for JA and linolenic acid Plant by with a a of with acid and with acid as a at a of and a of from to at with an used in JA, H2JA, linolenic acid, and at and JA, linolenic acid, H2JA, and from the and in that a and is for and including cell and to The and of JA, linolenic acid, H2JA, and are and which by in the the of JA, linolenic acid, H2JA, and of and to a of and for JA, linolenic acid, H2JA, and in the of the of and to by and the of and are used to JA and linolenic The of the used for of lipid lipid and lipid as R. H. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, E. P. R. R. 2006; PubMed Scopus Google Scholar). after of B. for lipid at the an The molecular species of phospholipids and galactolipids in to the a R. H. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, E. P. R. R. 2006; PubMed Scopus Google Scholar, R. R.A. PubMed Scopus Google Scholar). of for and to to the acyl and used to the levels of oxylipin molecular species C.M. P. S. R. Plant Physiol. 2006; PubMed Scopus Google Scholar). of the and oxylipin acyl in the of and the of and DGDG, used to the of the species of the specific oxylipin acyl with the the molecular species of and of AtPLAI hydrolysis in the of lipids from Arabidopsis as C.A. R. PubMed Scopus Google Scholar). from the lipids in a and the lipids in by as of lipid used as and of AtPLAI to the in a of 200 the of lipids and proteins that to the as the the resulting lipids and the by the as The in lipid the and AtPLAI by the of to the specific AtPLAI and of AtPLAI a for a protein of acid with a of and molecular of The with that of the AtPLAI gene with and a of and an of The of AtPLAI is most similar to intracellular calcium-independent in and but contains and AtPLAI contains and and from and and repeats of Armadillo and The is acid of the The is a acid in the gene E. R. Cell. Full Text PDF PubMed Scopus Google Scholar). The acid of AtPLAI is and similar to AtPLAI is more to a of proteins including from mammals, and than to the of proteins in Arabidopsis AtPLAI contains the at and a at and acid a for the acyl of of E. 2003; PubMed Scopus Google Scholar, J.W. PubMed Scopus Google Scholar). AtPLAI encodes an AtPLAI to a and in E. protein of to the of the protein to and for its to phosphatidylglycerol phosphatidic acid and used as and the of free fatty and free fatty and by the the at the sn-2 the of both and free fatty acid that the fatty at both sn-1 and sn-2 the at sn-1 and sn-2 positions, with from the lipid both free fatty acid and The of than that of acid, suggesting that the prefers hydrolysis of at the sn-1 to sn-2 The of that the to the fatty acid at the sn-1 as with the sn-2 PC, PE, or the but the sn-2 or the The and The of AtPLAI galactolipids than that of the phospholipids lipid lipids from plant used as for the and the resulting in phospholipids and galactolipids with The lipids that AtPLAI most MGDG, DGDG, and which are in AtPLAI or PE, the most phospholipids in that AtPLAI is an acyl rather than an AtPLAI oxygenated an lipid from Arabidopsis used as substrates. The species in the species, and C.M. P. S. R. Plant Physiol. 2006; PubMed Scopus Google and and AtPLAI both and galactolipids the of and by the to than that of and that AtPLAI use lipid species including as and a for to or of AtPLAI to B. T-DNA insertion of AtPLAI by the Wassilewskija of contains a T-DNA insertion at from the to acid after the of the the insertion at or acid after the The T-DNA in of the expression of AtPLAI as by the of the by mutant with resistance and in a suggesting that mutant contains a T-DNA insertion in the The mutant by the of AtPLAI with its The response of the T-DNA insertion to B. cinerea with plants. and mutant at the of the mutant plants more to B. as by increased and maceration of after infection than plants and plants of in the after infection, and the as with of the mutant plants The infection with B. cinerea in for of mutant in a of plants with the mutant plants after infection and the the AtPLAI gene the mutant the plants wild to the infection than the from the that the in the mutant plants is by the of the that of AtPLAI Arabidopsis more to B. cinerea. of AtPLAI the JA as to the in AtPLAI the defense the that of the acyl AtPLAI might JA production. the to the pathogen, most of the and to the of to infection, the basal level of JA in both mutant than that of with in The basal level of JA in the plants to that in that the level of JA to the of the of the AtPLAI JA the expression of involved in oxylipin and response in and mutant by infection, the expression levels of and and JA carboxyl and a 12-oxo-phytodienoic acid in than in mutant plants The level of a vegetative storage protein a in than in the mutant plants. The expression of involved in oxylipin response is with the level of JA in the mutant plants. the the levels of hydroperoxide and allene oxide similar the mutant and allene oxide and in the mutant than in plants. of AtPLAI JA plants with B. both and the exhibited in JA The at after and the at after The level of JA at the in than the The at after in by that by with a used for plants that but not with B. JA increased at in or mutant plants the of in JA from B. cinerea The AtPLAI mutant plants and pathogen-induced in JA, at a and similar to that of plants infection, the involved in oxylipin as AOS, and a similar of in both and not The level of free linolenic acid and after infection to of AtPLAI the of free linolenic acid, a for JA the basal level of free linolenic acid in more than than that in in the than in in the after the levels of free linolenic acid in the mutant than at after The in the level of free linolenic acid with the in JA in both and mutant plants and The levels of linolenic acid at in the as with to increased lipid hydrolysis and to the damage by infection in the mutant plant and in levels and B. cinerea infection for and mutant plants at the and in the plants with B. cinerea with to by a of are and mutant are with to and than and after B. cinerea the lipid changes after B. cinerea infection, polar species in and AtPLAI-deficient B. cinerea and species which the lipid PC, PE, PG, PI, MGDG, and DGDG, and PS, PA, lyso-PC, lyso-PE, and lyso-PG, as well as acyl species lipid is of changes in lipid species, as by known of specific lipid species an Arabidopsis lipid R. S. New York2005: Scholar). and similar of polar as of or of lipids not and with B. changes in phospholipids or galactolipids in or and not B. cinerea in phospholipids that in both and the mutant both the level in B. cinerea than that of that but with The from the species that is the acyl species R. H. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). The but the level of in both after the pathogen infection The in from linolenic species, and which are of and acyl R. H. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). plants with B. cinerea for or decreases in phospholipids and and more in and than did exhibited decreases in and than did after that of phospholipids to and in changes in or not in hydrolysis in than in plants is to the more damage in the but is that in hydrolysis is involved in JA biosynthesis JA at after infection and hydrolysis and after infection The similar in mutant and wild type that acyl rather than to the pathogen-induced lipid in of the AtPLAI Resistance to that of AtPLAI in decreases in basal JA, but not in pathogen-induced lipid hydrolysis or JA production. the resistance to B. cinerea in from a to to JA, and mutant plants with to B. cinerea mutant than but after the in the mutant plants and from plants The of pretreatment with the mutant response to B. cinerea and mutant plants with SA, the of both and mutant plants than plants of The in more in than in the The is with the that resulting in increased plant to B. cinerea. The of the AtPLAI to to JA and pretreatment that the increased in AtPLAI not from the to to JA or A. AtPLAI is most similar to mammalian iPLA2, and additionally contains Armadillo and at its proteins in including intracellular and Rev. 1999; PubMed Google Scholar). proteins in intracellular but for most of the proteins are in plants Trends Biol. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar). with include cell and P. PubMed Scopus Google Scholar, B. A.V. Curr. Opin. Biol. PubMed Scopus Google Scholar). are involved in a variety of as cell transcription, and the as a pathogen for plant resistance R. Curr. Opin. Plant Biol. 7: PubMed Scopus Google Scholar, P. Curr. Opin. Plant Biol. PubMed Scopus Google Scholar, Curr. Opin. Plant Biol. PubMed Scopus Google Scholar). the and of study the of AtPLAI and its role in JA production and defense The that AtPLAI is an acyl with lipid AtPLAI hydrolyzes phospholipids at the sn-1 and sn-2 and is more galactolipids than and DGDG, are in and expression in AtPLAI to in S. P. H. A. Plant PubMed Scopus Google Scholar). linolenic acid is to and involved in JA as and AOC, are in (4Blee E. Trends Plant Sci. 2002; 7: 315-322Abstract Full Text Full Text PDF PubMed Scopus (478) Google Scholar, 5Howe G.A. Schilmiller A.L. Curr. Opin. Plant Biol. 2002; 5: 230-236Crossref PubMed Scopus (402) Google Scholar). the and of AtPLAI in that AtPLAI plant its hydrolysis of plastidic lipids. of AtPLAI the of basal JA, not of pathogen-induced JA, the pathogen-induced hydrolysis of galactolipids or The of AtPLAI basal JA is by that the basal JA to the the positive role of AtPLAI in the basal JA is by a in the basal level of free linolenic acid and by reduced expression of the gene VSP2, level of expression is of JA levels in plants Mullet J.E. Plant Cell. 1990; Google Scholar, R.A. Mullet J.E. Plant Physiol. 1992; PubMed Scopus Google Scholar). The basal levels of expression in and of involved in JA biosynthesis are The level of gene expression for OPR, and is with the basal level of JA in the and the that JA biosynthesis is by a positive S. A. K. Plant Cell. PubMed Scopus Google Scholar, Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, B. H. H. Plant Mol. Biol. 2003; PubMed Scopus Google Scholar, A. Plant Physiol. 2006; PubMed Scopus Google Scholar). the the expression of and did not the The of a of expression and JA levels in Arabidopsis H. S. Plant Physiol. 2002; PubMed Scopus Google Scholar, C.A. R. Plant Cell. PubMed Scopus Google Scholar). the of to changes H. S. Plant Physiol. 2002; PubMed Scopus Google Scholar). It is that Arabidopsis basal and which basal JA altered gene is an JA biosynthesis with lipids or free fatty The that as as precursors for JA that the free linolenic acid is not to provide the of JA production after the is to oxygenated and and is more for and oxygenated and are in in response to the shows is more oxygenated than MGDG, which is with the changes in lipid species The in lipids from linolenic species, and species are of and acyl E. P. R. R. 2006; PubMed Scopus Google Scholar, R. S. New York2005: Scholar). the level of the not and decreases in phospholipids and after infection in plants. The increased hydrolysis of and is with in and lyso-PC, which and after The in hydrolysis in AtPLAI-deficient plants is with more rather than the of JA production. in hydrolysis are to more to than to the of JA production. The that acyl or rather than to the lipid in the plastidic lipid hydrolysis and the of the that the AtPLAI-deficient plants as or JA as One the of The Arabidopsis contains and of to acyl The are with and and with and S. P. H. A. Plant PubMed Scopus Google Scholar, A. S. H. Plant Physiol. 2002; PubMed Scopus Google Scholar). AtPLAI and proteins the and a acid as a for lipid acyl K. B. Plant Cell. 2006; PubMed Scopus Google Scholar, E. P. R. R. 2006; PubMed Scopus Google Scholar). proteins and to acyl S. P. H. A. Plant PubMed Scopus Google Scholar, A. S. H. Plant Physiol. 2002; PubMed Scopus Google Scholar, S. A. PubMed Scopus Google but role in JA production is the is to pathogen A. S. H. Plant Physiol. 2002; PubMed Scopus Google and not JA and the proteins not the the in the is with a and the acid in the is with a protein in to acyl is the proteins acyl the proteins to the basal or pathogen-induced JA in the AtPLAI mutant to is that of or pathogen-induced JA are of in Arabidopsis Trends Plant Sci. Full Text Full Text PDF PubMed Scopus Google Scholar). that phospholipase of free linolenic acid and JA in A. thaliana C.A. R. PubMed Scopus Google Scholar, H. S. Plant Physiol. 2002; PubMed Scopus Google Scholar). The that production of basal JA and JA is by JA is well to a positive role in plant response to necrotrophic pathogen infection (12Thomma B.P. Eggermont K. Mauch-Mani B. R. B.P. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar). As by study and JA after and H. Muller M.J. Kutchan T.M. Zenk M.H. Proc. Natl. Acad. Sci. U. S. A. 1992; 89: 2389-2393Crossref PubMed Scopus (999) Google Scholar, R.A. Mullet J.E. Proc. Natl. Acad. Sci. U. S. A. 1992; 89: PubMed Scopus Google Scholar). the of basal pathogen-induced JA plant defense are not and is known the role of basal level of JA in defense The that the plants are more to B. cinerea the a similar of pathogen-induced One for the the in pathogen-induced JA and the in B. cinerea resistance in is that of AtPLAI might the plant to to is pretreatment of AtPLAI-deficient with JA the to to and mutant plants with SA, the of both and mutant plants than plants of and JA of and defense in Arabidopsis and to in Arabidopsis in response to (12Thomma B.P. Eggermont K. Mauch-Mani B. R. B.P. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, A. Ryan C.A. Plant Physiol. PubMed Scopus Google Scholar, K. H. Plant Physiol. PubMed Scopus Google Scholar). The is with the that resulting in increased plant to B. cinerea. that plants to to JA and the that AtPLAI is an acyl hydrolase, rather than a specific to AtPLAI as acyl the study that induced JA is not for defense B. and that the basal level of JA is important in defense that the acyl of AtPLAI is involved in the of basal free fatty and basal JA that plays a positive role in defense of for in lipid