Contribution of salicylic acid glucosyltransferase, OsSGT1, to chemically induced disease resistance in rice plants

Abstract

Summary Systemic acquired resistance (SAR), a natural disease response in plants, can be induced chemically. Salicylic acid (SA) acts as a key endogenous signaling molecule that mediates SAR in dicotyledonous plants. However, the role of SA in monocotyledonous plants has yet to be elucidated. In this study, the mode of action of the agrochemical protectant chemical probenazole was assessed by microarray‐based determination of gene expression. Cloning and characterization of the most highly activated probenazole‐responsive gene revealed that it encodes UDP‐glucose:SA glucosyltransferase (OsSGT1), which catalyzes the conversion of free SA into SA O‐β‐glucoside (SAG). We found that SAG accumulated in rice leaf tissue following treatment with probenazole or 2,6‐dichloroisonicotinic acid. A putative OsSGT1 gene from the rice cultivar Akitakomachi was cloned and the gene product expressed in Escherichia coli was characterized, and the results suggested that probenazole‐responsive OsSGT1 is involved in the production of SAG. Furthermore, RNAi‐mediated silencing of the OsSGT1 gene significantly reduced the probenazole‐dependent development of resistance against blast disease, further supporting the suggestion that OsSGT1 is a key mediator of development of chemically induced disease resistance. The OsSGT1 gene may contribute to the SA signaling mechanism by inducing up‐regulation of SAG in rice plants.

Metabolic movement upon abscisic acid and salicylic acid combined treatments

“…In Arabidopsis, overexpression of SAGT led to increased susceptibility to Pseudomonas syringae (Song et al 2008). Umemura et al proposed that SAG possibly contributes to SAR by serving as a natural regulator in rice plant (Umemura et al 2009). We found that the signal intensity of SAG decreased proportionally along with the ABA treatment period and the ABA concentration regardless of the SA concentration.…”

Peroxyacetyl nitrate-induced oxidative and calcium signaling events leading to cell death in ozone-sensitive tobacco cell-line

“…13 Recently, involvement of SA glucosyltransferase which converts SA to its glucoside in chemical induction of defense mechanism has been demonstrated in rice plants. 14 At gene expression level (examining the SA-responsive gene expression with micro-array) 15 and molecular genetic level (using SA-related mutant cell lines), 7 involvement of SA signal transduction pathway in O 3 response in Arabidopsis thaliana have been proven.…”

Identification of Rice β-Glucosidase with High Hydrolytic Activity towards Salicylic Acid β-D-Glucoside

“…Optimization of the production of rOsTAGG2P The culture medium of the transformant of P. pastoris carrying the expression cassette for OsTAGG2 showed 0.5 U/mL after induction at 30 C for 96 h, but the enzyme produced barely adsorbed onto a Ni-chelating Sepharose column (data not shown). His 6 -tag antibodies detected no band in the non-adsorbed fraction, suggesting that the His 6 -tag has been removed or destroyed during culture.…”

“…Cells were collected by centrifugation and suspended in 10 mL of BMMY medium (10 mg/mL of glycerol in BMGY was changed to 0.5% v/v methanol). The cell suspension was further incubated at 30 C for 96 h. Protein production was maintained by the addition of methanol at a final concentration of 0.5% v/v every 24 h. The enzyme activity of the culture supernatant of each transformant was measured as described below. The transformant with the highest productivity of recombinant OsTAGG2 was selected for further analysis.…”