An injury-response mechanism conserved across kingdoms determines entry of the fungus Trichoderma atroviride into development

Abstract

A conserved injury-defense mechanism is present in plants and animals, in which the production of reactive oxygen species (ROS) and lipid metabolism are essential to the response. Here, we describe that in the filamentous fungus Trichoderma atroviride, injury results in the formation of asexual reproduction structures restricted to regenerating cells. High-throughput RNA-seq analyses of the response to injury in T. atroviride suggested an oxidative response and activation of calcium-signaling pathways, as well as the participation of lipid metabolism, in this phenomenon. Gene-replacement experiments demonstrated that injury triggers NADPH oxidase (Nox)-dependent ROS production and that Nox1 and NoxR are essential for asexual development in response to damage. We further provide evidence of H 2 O 2 and oxylipin production that, as in plants and animals, may act as signal molecules in response to injury in fungi, suggesting that the three kingdoms share a conserved defense-response mechanism.conidiation | stress | transcriptome

Trichoderma Research in the Genome Era

“…These observations led to the suggestion of the involvement of NADPH oxidases (Nox) in the process. Gene replacement of the two catalytic subunits of Nox confirmed that Nox1 is indeed a determinant for injury-induced conidiation (54). The availability of these data in a temporal frame allows the identification of genes involved in the morphogenetic transition independently of the cue triggering the process.…”

“…Most laboratory strains produce conidia and chlamydospores, and in nature some form ascospores in perithecia. The transition from vegetative growth to conidiation can be triggered in Trichoderma by UV-blue light, nutrient deprivation, low pH, or mechanical damage to the mycelium (15,43,54,56,71 …”

The Genomes of Three Uneven Siblings: Footprints of the Lifestyles of Three Trichoderma Species

“…To explore these factors, the transcriptomes regulated in response to different stimuli, such as light, injury, and mycoparasitism (Trichoderma-host fungus interaction) were analyzed. Several components of DNA re-pair systems were found to be responsive to light, injury, and mycoparasitism, as revealed by transcriptome data (15,22,1313). Mycelial injury exerts a greater impact on genes involved in DNA repair (12 genes induced and 3 repressed) than light (7 genes induced) or mycoparasitism (7 genes repressed).…”

“…Besides being extensively used as biological control agents and biofactories (6), several members of the genus Trichoderma have emerged as fungal models for understanding (i) asexual reproduction (7,(12)(13)(14), (ii) light and oxidative stress signaling (12,15), (iii) mechanisms of vesicle transport and secretory pathways (16,17), and (iv) synthesis of lytic enzymes and antifungal secondary metabolites (16,(18)(19)(20). Furthermore, Trichoderma spp.…”

Gigaspora margarita with and without its endobacterium shows adaptive responses to oxidative stress

“…Oxidative stresses can originate from endogenous or exogenous sources and may play different roles. On the one hand, H2O2 may act as a signal in response to injury in fungi such as Trichoderma and Rhizophagus irregularis, suggesting that fungi share a defense mechanism based on ROS-related molecules, as is common in plants and animals (Hernández-Oñate et al 2012;Fester and Hause 2005). On the other hand, environmental stimuli can lead to oxidative stress; for example, a recent study reported that the glutathione peroxidase redox system is directly involved in the resistance of Alternaria alternata to the fungicides fludioxonil and vinclozolin (Yang et al 2016).…”