Oxidative stress response of Mycosphaerella fijiensis, the causal agent of black leaf streak disease in banana plants, to hydrogen peroxide and paraquat

Abstract

Mycosphaerella fijiensis causes black leaf streak disease in banana and plantain. This fungus is usually attacked by reactive oxygen species secreted by the plant or during exposure to fungicide, however, little is known about the antioxidant response of the fungus. In this study, mycelia were observed to totally decompose 30 mmol/L of hydrogen peroxide (H2O2) within 120 min, liberating oxygen bubbles, and also to survive in concentrations as high as 100 mmol/L H2O2. The oxidative stress responses to H2O2, paraquat, and hydroquinone were characterized in terms of the activities of catalase and superoxide dismutase (SOD). Two active catalase bands were seen in native PAGE induced by H2O2. Band I had monofunctional activity and band II had bifunctional catalase-peroxidase activity. Two isozymes of SOD, distinguishable by their cyanide sensitivity, were found; CuZnSOD was the main one. The combination of H2O2 and 3-aminotriazole reduced the accumulation of biomass up to 40% compared with exposure to H2O2 alone, suggesting that catalase is important for the rapid decomposition of H2O2 and has a direct bearing on cell viability. The results also suggest that the superoxide anion formed through the redox of paraquat and hydroquinone has a greater effect than H2O2 on the cellular viability of M. fijiensis.

Probiotic Endophytes for More Sustainable Banana Production

“…Our research group has studied black Sigatoka from two scientific approaches to reduce the impact of black Sigatoka in bananas: a) the biochemistry and physiology of P. fijiensis and b) the endophytic bacteria populations and their usefulness as probiotics in commercial plantations of Colima and Jalisco, Mexico [ 5 , 18 , 116 , 117 , 118 ]. First, we proposed E. cloacae , which is widely distributed in banana plants and seeds [ 18 , 30 , 119 , 120 ], as a keystone member of the microbial community of these plants.…”

Mycosphaerella fijiensis, the black leaf streak pathogen of banana: progress towards understanding pathogen biology and detection, disease development, and the challenges of control

“…The significant degree of resistance detected in the Mycosphaerella banana pathogens to the reactive oxygen‐generating dyes suggests that they have the potential to synthesize similar compounds that could play roles in pathogen virulence (Daub and Ehrenshaft, 2000). Beltrán‐García et al . (2009) recently characterized the oxidative stress response of M. fijiensis after exposure to hydrogen peroxide and paraquat to assess the potential defensive capabilities of the fungus in response to the predicted oxidative stresses imposed by plant defence mechanisms and fungicide exposure.…”

Singlet Molecular Oxygen Generation by Light-Activated DHN-Melanin of the Fungal Pathogen Mycosphaerella fijiensis in Black Sigatoka Disease of Bananas

“…This fungus is responsible for more than 50% of the crop losses in productions areas. M. fijiensis shows high levels of genetic diversity, aggressiveness and resistance to fungicides and ROS [18], [19], [20]. This fungus accumulates and secretes a dark-green pigment on the surface of the colony and into potato-dextrose agar.…”