Activity of Class III Peroxidases in the Defense of Cotton to Bacterial Blight

Abstract

Cotton cotyledons displayed a hypersensitive reaction (HR) in the cultivar Réba B50 after infiltration with the avirulent race 18 from Xanthomonas campestris pv. malvacearum. Two sets of peroxidases were associated with the HR time course. Early but transient accumulation of peroxidase in material encapsulating the bacteria in intercellular areas was observed by immunocytochemistry at 3 h postinfection and coincided with the oxidative burst. Total guaiacol-peroxidase activity was highly increased in cells undergoing HR, from 12 h after treatment. Molecular characterization of seven cloned peroxidase genes revealed highly conserved B, D, and F domains, with similarities to plant class III peroxidases. Analysis of gene expression showed variation in transcript accumulation during both compatible (race 20) and incompatible interactions for four of these genes: pod2, pod3, pod4, and pod6. Pod4 and pod6 were more intensely up-regulated during resistance than during disease and in the control, while pod3 was specifically down-regulated during the HR after the oxidative burst. Pod2 was induced by pathogen infection and weakly stimulated in the control. These data suggest that cotton peroxidases may have various functions in the defense response to Xanthomonas infections.

Peroxidases have more functions than a Swiss army knife

“…Production and accumulation of superoxide anions and hydrogen peroxide in cell wall has been related to the presence of pathogens (Martinez et al 1998). Total peroxidase activity is highly increased in the infected region 12 h after treatment and mainly localised in the apoplast and close to the bacterial infection site (Martinez et al 1998;Delannoy et al 2003). Similarly, rice leaves infected by rice blight (Xanthomonas oryzae pv.…”

Arabidopsis peroxidase AtPRX53 influences cell elongation and susceptibility toHeterodera schachtii

“…[16][17][18] Genes coding for class III peroxidases have been duplicated extensively during evolution and thus form large gene families in all land plant species studied. 16 Some of these enzymes have been shown to be involved in a wide range of physiological and developmental processes, which include cross-linking of cell wall components during cell wall formation and modification, 19,20 Accumulated experimental evidence also implicates class III peroxidases in plant defense responses to pathogen/pest attacks, such as bacteria, [25][26][27] fungi, 28 viruses, 29 insects 30 and cyst nematodes. 31 Two major functional roles have been attributed to class III peroxidases in response to pathogen attack.…”

Defense related enzyme induction in coconut by endophytic bacteria (EPC 5)

“…Recently, several peroxidase genes were cloned and studied in cotton plants during compatible and incompatible interactions with X. campestris pv. malvacearum (Delannoy et al, 2003). The PPO activity was higher in bioconsortia compared to individual treatments.…”