Activation of a Bean Chitinase Promoter in Transgenic Tobacco Plants by Phytopathogenic Fungi

Abstract

The temporal and spatial expression of a bean chitinase promoter has been investigated in response to fungal attack. Analysis of transgenic tobacco plants containing a chimeric gene composed of a 1.7-kilobase fragment carrying the chitinase 5B gene promoter fused to the coding region of the gus A gene indicated that the chitinase promoter is activated during attack by the fungal pathogens Botrytis cinerea, Rhizoctonia solani, and Sclerotium rolfsii. Although induction of 8-glucuronidase activity was observed in tissues that had not been exposed to these phytopathogens, the greatest induction occurred in and around the site of fungal infection. The increase in 8-glucuronidase activity closely paralleled the increase in endogenous tobacco chitinase activity produced in response to fungal infection. Thus, the chitinase 5B-gus A fusion gene may be used to analyze the cellular and molecular details of the activation of the host defense system during pathogen attack.

A LysM Receptor-Like Kinase Plays a Critical Role in Chitin Signaling and Fungal Resistance inArabidopsis

“…It was hypothesized that plant chitinases can degrade chitin in the fungal cell walls to directly affect the viability of the invading fungal pathogen and to release short chitin fragments (chitooligosaccharides) that can act as a general elicitor of plant innate immunity (Boller, 1995;Stacey and Shibuya, 1997;Shibuya and Minami, 2001;Passarinho and de Vries, 2002). This hypothesis is indirectly supported by the following observations: a number of chitinase genes are induced by fungal infection (Majeau et al, 1990;Roby et al, 1990), and chitinases accumulate at infection sites in planta (Wubben et al, 1992). Chitinases were also shown to degrade fungal cell walls and inhibit fungal growth in vitro, especially in combination with b-1,3-glucanases (Schlumbaum et al, 1986;Mauch et al, 1988;Arlorio et al, 1992;van den Burg et al, 2006).…”

The Primary Structure of Plant Pathogenesis-related Glucanohydrolases and Their Genes

“…Similar studies have shown that all the elements needed for correct hormonal, developmentaf and pathogenesis regulated expression are present in a ""'1.6 kb 5'-fragment of the tobacco ~-1,3-glucanase gene GLB (R. Vogeli-Lange et al, 1991). A 1.7 kb fragment from the 5'-region of the bean chitinase gene 5B was sufficient for induction of GUS in response to infection with fungal pathogens and treatment with ethylene (Broglie et al, 1989;Roby et al, 1990). Deletion analysis of this fragment showed that the sequence between -422 and -195 upstream of the transcriptional start site is important both for constitutive expression and ethylene-induced expression (Broglie et al, 1989).…”

Pathogenesis-Related Proteins and Plant Defense

“…TissuespeciJic expression of defense responses has been studied by quantifying various defense responses, enzyme activities, and mRNA amounts, after localized tissue sampling (Bell et al 1986;Schroder et al 1992;Meier et al 1993), by in situ localization of proteins and mRNA in sections of infectcd tissues (Somssich et al 1988;Schmelzer et al 1989;Taylor et al 1990;Benhamou 1993;Kombrink et al 1993a), or by histochemical analysis of the products of reporter genes driven by promoters of defense-related genes in transgenic plants (Castresana et al 1990;Roby et al 1990;Samac and Shah 1991;Hennig et al 1993;Martini et al 1993;Warner et al 1993). In general, these studies show that the patterns of expression and localization of PR proteins and transcripts differ greatly.…”