Oxidative Stress in Entomopathogenic Fungi and Its Potential Role on Mycoinsecticide Enhancement

HUARTE-BONNET CARLA; MANNINO MARIA CONSTANZA; PEDRINI NICOLÁS

Microbes for sustainable Insect Pest Management

Springer International Publishing

Año: 2019; p. 201 - 209

Entomopathogenic fungi (EF) are used worldwide as environmentally friendlymycoinsecticides. A successful invasion process depends on the fungal abilityto cope with several stress factors, such as osmotic stress, temperature, UVradiation, and oxidative stress. Reactive oxygen species (ROS) can appear dueto either previous environmental stresses or endogenous metabolic changes.Moreover, ROS may be either part of the host defense against fungi or thefungus itself can release ROS in the hemolymph to overcome insect defenses.Regardless of its source, fungi must mitigate ROS damage in their cells.Antioxidant response in fungi involves the action of enzymes as well as nonenzymatic compounds. Oxidative stress and antioxidant responses are known tohave several direct and/or indirect consequences in fungal adaptation. Nutritivestress produced by non-preferred carbohydrate sources in conidia production canincrease ROS scavengers consequently enhancing UV tolerance. Additionally,growth in long chain cuticular hydrocarbons triggers ROS production andantioxidant gene induction, leading to more virulent conidia. Also, ROS canact as signaling molecules for cell differentiation into new propagules such asmicrosclerotia and mycelial pellets that tolerate desiccation and produce newinfective conidia in the field. In this chapter we will summarize ROS sourcesand antioxidant scavengers during conidial production and fungal invasion intotheir hosts, and the beneficial consequences for stress tolerance, virulence andcell differentiation that can arise from these initial drawbacks.