Overexpression of AtSGT1, an Arabidopsis salicylic acid glucosyltransferase, leads to increased susceptibility to Pseudomonas syringae.
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.
Song
Jong Tae
JT
School of Applied Biosciences, Kyungpook National University, Daegu 702-701, Republic of Korea. jtsong68@knu.ac.kr
Koo
Yeon Jong
YJ
Seo
Hak Soo
HS
Kim
Min Chul
MC
Choi
Yang Do
YD
Kim
Jeong Hoe
JH
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
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