HSR203 antisense suppression in tobacco accelerates development of hypersensitive cell death

Abstract

SummaryActivation of the tobacco gene hsr203 is rapid, highly localized, speci®c for incompatible plant±pathogen interactions, and strongly correlated with programmed cell death occurring in response to diverse pathogens. Functional characterization of hsr203 gene product has shown that HSR203 is a serine hydrolase that displays esterase activity. We show here that transgenic tobacco plants de®cient in HSR203 protein exhibit an accelerated hypersensitive response when inoculated with an avirulent strain of Ralstonia solanacearum. This response was accompanied by a maximal level of cell death and a drastic inhibition of in planta bacterial growth. Transgenic plants de®cient in HSR203 were also found to show increased resistance in a dosage-dependent manner to Pseudomonas syringae pv. pisi, another avirulent bacterial pathogen, and to virulent and avirulent races of Phytophthora parasitica, a fungal pathogen of tobacco, but not to different virulent bacteria. Surprisingly, expression of another hsr gene, hsr515, and that of the defence genes PR1-a and PR5, was strongly reduced in the transgenic lines. Our results suggest that hsr203 antisense suppression in tobacco can have pleiotropic effects on HR cell death and defence mechanisms, and induces increased resistance to different pathogens.

A R2R3-MYB gene, AtMYB30 , acts as a positive regulator of the hypersensitive cell death program in plants in response to pathogen attack

“…However, the corresponding Pseudomonas virulent strain does not provoke HR-like symptoms on tobacco overexpressing Pti1, in contrast to our system. The same comment can be made for engineered hsr203 transgenic plants (15). This finding suggests that AtMYB30, whatever its role in HR development, might act in a critical signaling step preceding cell death.…”

“…In contrast, decreased production of a chloroplastic protease (FtsH) in tobacco (34) led to an acceleration of the HR induced by tobacco mosaic virus. More recently, antisense expression of hsr203 was also shown to confer an acceleration of the HR in tobacco in response to diverse pathogens (15). All of these genes have a potential regulatory function in the HR, although their exact mode of action remains unknown.…”

“…We have previously identified genes that are specifically expressed during the HR in tobacco (13) and Arabidopsis (14) and shown for one of them a role of negative regulator of the HR (15). Among them, an R2R3 MYB-related gene in Arabidopsis thaliana, AtMYB30, was isolated on the basis of its specific, rapid, and transient transcriptional activation during the very first steps of the HR in response to the avirulent strain 147 of Xanthomonas campestris pv.…”

Nicotiana benthamiana gp91phox Homologs NbrbohA and NbrbohB Participate in H2O2 Accumulation and Resistance to Phytophthora infestans

“…Therefore, reverse transcriptase-mediated (RT) PCR with genespecific primers was performed. We also used primers for hsr203J (Tronchet et al, 2001) and EF-1 ␣ as controls for an induced and a constitutively expressed gene, respectively (Figure 3). …”

Expression of Genes Related with Defense Responses against Pathogen Infections in Vitis flexuosa

“…The Arabidopsis RPS5 gene is activated by AvrPphB mediated cleavage of the protein kinase PBS1 and engages in downstream signaling molecules that activate the defense response (Feys and Parker 2000;Ade et al 2007;Qi et al 2012). Several CXE genes, including hsr203J (tobacco), Lehsr203 (tomato), BIG8.1 (Botrytis-induced grapevine), PepEST (Pepper), and SOBER1 (Arabidopsis), were characterized as hypersensitivity-related genes (Baudouin et al 1997;Tronchet et al 2001;Bézier et al 2002;Ko et al 2005). EDS1 plays an important role in the R gene mediated defense signaling pathway (Aarts et al 1998;Rietz et al 2011).…”