Overexpression of salicylic acid carboxyl methyltransferase reduces salicylic acid-mediated pathogen resistance in Arabidopsis thaliana.
We cloned a salicylic acid/benzoic acid carboxyl methyltransferase gene, OsBSMT1, from Oryza sativa. A recombinant OsBSMT1 protein obtained by expressing the gene in Escherichia coli exhibited carboxyl methyltransferase activity in reactions with salicylic acid (SA), benzoic acid (BA), and de-S-methyl benzo(1,2,3)thiadiazole-7-carbothioic acid (dSM-BTH), producing methyl salicylate (MeSA), methyl benzoate (MeBA), and methyl dSM-BTH (MeBTH), respectively. Compared to wild-type plants, transgenic Arabidopsis overexpressing OsBSMT1 accumulated considerably higher levels of MeSA and MeBA, some of which were vaporized into the environment. Upon infection with the bacterial pathogen Pseudomonas syringae or the fungal pathogen Golovinomyces orontii, transgenic plants failed to accumulate SA and its glucoside (SAG), becoming more susceptible to disease than wild-type plants. OsBSMT1-overexpressing Arabidopsis showed little induction of PR-1 when treated with SA or G. orontii. Notably, incubation with the transgenic plant was sufficient to trigger PR-1 induction in neighboring wild-type plants. Together, our results indicate that in the absence of SA, MeSA alone cannot induce a defense response, yet it serves as an airborne signal for plant-to-plant communication. We also found that jasmonic acid (JA) induced AtBSMT1, which may contribute to an antagonistic effect on SA signaling pathways by depleting the SA pool in plants.
Koo
Yeon Jong
YJ
School of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Korea.
Kim
Myeong Ae
MA
Kim
Eun Hye
EH
Song
Jong Tae
JT
Jung
Choonkyun
C
Moon
Joon-Kwan
JK
Kim
Jeong-Han
JH
Seo
Hak Soo
HS
Song
Sang Ik
SI
Kim
Ju-Kon
JK
Lee
Jong Seob
JS
Cheong
Jong-Joo
JJ
Choi
Yang Do
YD
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000382:microbiology / Q000502:physiology; D001203:Ascomycota / Q000502:physiology; D003001:Cloning, Molecular; D003517:Cyclopentanes / Q000378:metabolism; D007113:Immunity, Innate / Q000235:genetics; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics; D054883:Oxylipins; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D030821:Plants, Genetically Modified / Q000201:enzymology* / Q000378:metabolism / Q000382:microbiology; D044224:Pseudomonas syringae / Q000502:physiology; D011994:Recombinant Proteins / Q000378:metabolism; D012459:Salicylates / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D016415:Sequence Alignment
D003517:Cyclopentanes; D054883:Oxylipins; D010940:Plant Proteins; D011994:Recombinant Proteins; D012459:Salicylates; C011006:jasmonic acid; D008780:Methyltransferases; C110994:salicylic acid carboxyl methyltransferase; C033069:methyl salicylate; D020156:Salicylic Acid