The expression patterns of AtBSMT1 and AtSAGT1 encoding a salicylic acid (SA) methyltransferase and a SA glucosyltransferase, respectively, in Arabidopsis plants with altered defense responses.
We reported previously that overexpression of a salicylic acid (SA) methyltransferase1 gene from rice (OsBSMT1) or a SA glucosyltransferase1 gene from Arabidopsis thaliana (AtSAGT1) leads to increased susceptibility to Pseudomonas syringae due to reduced SA levels. To further examine their roles in the defense responses, we assayed the transcript levels of AtBSMT1 or AtSAGT1 in plants with altered levels of SA and/or other defense components. These data showed that AtSAGT1 expression is regulated partially by SA, or non-expressor of pathogenesis related protein1, whereas AtBSMT1 expression was induced in SA-deficient mutant plants. In addition, we produced the transgenic Arabidopsis plants with RNAi-mediated inhibition of AtSAGT1 and isolated a null mutant of AtBSMT1 and then analyzed their phenotypes. A T-DNA insertion mutation in the AtBSMT1 resulted in reduced methyl salicylate (MeSA) levels upon P. syringae infection. However, accumulation of SA and glucosyl SA was similar in both the atbsmt1 and wild-type plants, indicating the presence of another SA methyltransferase or an alternative pathway for MeSA production. The AtSAGT1-RNAi line exhibited no altered phenotypes upon pathogen infection, compared to wild-type plants, suggesting that (an)other SA glucosyltransferase(s) in Arabidopsis plants may be important for the pathogenesis of P. syringae.
Song
Jong Tae
JT
School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Korea. jtsong68@knu.ac.kr
Koo
Yeon Jong
YJ
Park
Jong-Beum
JB
Seo
Yean Joo
YJ
Cho
Yeon-Jeong
YJ
Seo
Hak Soo
HS
Choi
Yang Do
YD
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D015152:Blotting, Northern; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D005964:Glucosyltransferases / Q000235:genetics* / Q000378:metabolism; D054884:Host-Pathogen Interactions; D007113:Immunity, Innate / Q000235:genetics; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D015394:Molecular Structure; D009154:Mutation; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D030821:Plants, Genetically Modified; D044224:Pseudomonas syringae / Q000502:physiology; D034622:RNA Interference; D012459:Salicylates / Q000737:chemistry / Q000378:metabolism; D020156:Salicylic Acid / Q000737:chemistry / Q000378:metabolism*
D029681:Arabidopsis Proteins; D005964:Glucosyltransferases; D008780:Methyltransferases; D012459:Salicylates; D020156:Salicylic Acid; C546901:BSMT1 protein, Arabidopsis; C489364:glucosyltransferase I; C033069:methyl salicylate; C515668:SGT1 protein, Arabidopsis