Secretome analysis reveals an Arabidopsis lipase involved in defense against Alternaria brassicicola.
The Arabidopsis thaliana secretome was analyzed by the proteomic approach, which led to the identification of secreted proteins implicated in many aspects of cell biology. We then investigated the change in the Arabidopsis secretome in response to salicylic acid and identified several proteins involved in pathogen response. One of these, a secreted lipase with a GDSL-like motif designated GDSL LIPASE1 (GLIP1), was further characterized for its function in disease resistance. glip1 plants were markedly more susceptible to infection by the necrotrophic fungus Alternaria brassicicola compared with the parental wild-type plants. The recombinant GLIP1 protein possessed lipase and antimicrobial activities that directly disrupt fungal spore integrity. Furthermore, GLIP1 appeared to trigger systemic resistance signaling in plants when challenged with A. brassicicola, because pretreatment of the glip1 mutant with recombinant GLIP1 protein inhibited A. brassicicola-induced cell death in both peripheral and distal leaves. Moreover, glip1 showed altered expression of defense- and ethylene-related genes. GLIP1 transcription was increased by ethephon, the ethylene releaser, but not by salicylic acid or jasmonic acid. These results suggest that GLIP1, in association with ethylene signaling, may be a critical component in plant resistance to A. brassicicola.
Oh
Il Seok
IS
School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
Park
Ae Ran
AR
Bae
Min Seok
MS
Kwon
Sun Jae
SJ
Kim
Young Soon
YS
Lee
Ji Eun
JE
Kang
Na Young
NY
Lee
Sumin
S
Cheong
Hyeonsook
H
Park
Ohkmae K
OK
D000528:Alternaria / Q000502:physiology*; D020816:Amino Acid Motifs / Q000235:genetics; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002478:Cells, Cultured; D017124:Conserved Sequence / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics*; D008049:Lipase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009943:Organophosphorus Compounds / Q000494:pharmacology; D010935:Plant Diseases / Q000235:genetics*; D040901:Proteomics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D020156:Salicylic Acid / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics
D029681:Arabidopsis Proteins; D009943:Organophosphorus Compounds; D011993:Recombinant Fusion Proteins; D002265:Carboxylic Ester Hydrolases; C508002:Glip1 protein, Arabidopsis; D008049:Lipase; D020156:Salicylic Acid; C005073:ethephon