title: Overexpression of AtSGT1, an Arabidopsis salicylic acid glucosyltransferase, leads to increased susceptibility to Pseudomonas syringae.
abstract: We reported previously that a recombinant salicylic acid (SA) glucosyltransferase1 (AtSGT1) from Arabidopsis thaliana catalyzes the formation of both SA 2-O-beta-D-glucoside (SAG) and the glucose ester of SA (SGE). Here, transgenic Arabidopsis plants overexpressing AtSGT1 have been constructed, and their phenotypes analyzed. Compared to wild-type plants, transgenic plants showed an increased susceptibility to Pseudomonas syringae and reduced the accumulation levels of both free SA and its glucosylated forms (SAG and SGE). On the other hand, the overexpression increased the levels of methyl salicylate (MeSA) and methyl salicylate 2-O-beta-D-glucoside (MeSAG), and also induced SA carboxyl methyltransferase1 (AtBSMT1) expression, whose products catalyze the conversion of SA to MeSA. Our data indicate that reduced resistance by AtSGT1 overexpression results from a reduction in SA content, which is at least in part caused by increases in MeSAG and MeSA levels at the expense of SA. Our study also suggests that genetic manipulation of AtSGT1 can be utilized as an important regulatory tool for pathogen control.
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu 702-701, Republic of Korea. jtsong68@knu.ac.kr
authors.forename: Jong Tae
authors.initials: JT
authors.lastname: Song
authors.forename: Yeon Jong
authors.initials: YJ
authors.lastname: Koo
authors.forename: Hak Soo
authors.initials: HS
authors.lastname: Seo
authors.forename: Min Chul
authors.initials: MC
authors.lastname: Kim
authors.forename: Yang Do
authors.initials: YD
authors.lastname: Choi
authors.forename: Jeong Hoe
authors.initials: JH
authors.lastname: Kim
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics*; D015152:Blotting, Northern; D004789:Enzyme Activation / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D005960:Glucosides / Q000032:analysis; D005964:Glucosyltransferases / Q000235:genetics*; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000201:enzymology / Q000382:microbiology; D044224:Pseudomonas syringae / Q000502:physiology*; D012459:Salicylates / Q000032:analysis; D020156:Salicylic Acid / Q000032:analysis
chemical_list: D029681:Arabidopsis Proteins; D005960:Glucosides; D012459:Salicylates; C530519:methyl salicylate 2-O-beta-D-glucoside; D005964:Glucosyltransferases; C515668:SGT1 protein, Arabidopsis; C033069:methyl salicylate; D020156:Salicylic Acid