Multiple Roles and Effects of a Novel Trichoderma Hydrophobin

Abstract

Fungi belonging to the genus Trichoderma are among the most active and ecologically successful microbes found in natural environments, because they are able to use a variety of substrates and affect the growth of other microbes and virtually any plant species. We isolated and characterized a novel type II hydrophobin secreted by the biocontrol strain MK1 of Trichoderma longibrachiatum. The corresponding gene (Hytlo1) has a multiple role in the Trichoderma-plant-pathogen three-way interaction, while the purified protein displayed a direct antifungal as well as a microbe-associated molecular pattern and a plant growth promotion (PGP) activity. Leaf infiltration with the hydrophobin systemically increased resistance to pathogens and activated defense-related responses involving reactive oxygen species, superoxide dismutase, oxylipin, phytoalexin, and pathogenesis-related protein formation or activity. The hydrophobin was found to enhance development of a variety of plants when applied at very low doses. It particularly stimulated root formation and growth, as demonstrated also by transient expression of the encoding gene in tobacco and tomato. Targeted knock-out of Hytlo1 significantly reduced both antagonistic and PGP effect of the wild-type strain. We conclude that this protein represents a clear example of a molecular factor developed by Trichoderma spp. to establish a mutually beneficial interaction with the colonized plant.

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

“…EIX has a dual role during plant colonization: the first role involves lytic enzyme activity, while the second involves the induction of systemic resistance as seen in specific cultivars of tobacco and tomato (1231)(1232)(1233)(1234). Moreover, hydrophobins were shown to be involved in Trichoderma-plant interactions (1235,1236). In theory, endophytes should modulate the immune response of the plant as they must overcome the plant MAMP immune responses in order to establish successfully in the intercellular space (apoplast) or into restricted cellular areas, as in the case of mycorrhizae.…”

“…For example, the hydrophobin-like TasHyd1 protein, isolated from T. asperellum, plays an important role in root attachment and colonization (1236). One of the biological functions of hydrophobins is the recognition and adhesion to host surfaces, where they positively influence root colonization ability (337,1236) and act as elicitors of the plant defense response (1235,1266). Moreover, hydrophobins have an important role in plant-fungus recognition in M. grisea (1267) and T. asperellum (1236).…”

Organic substrate for transplant production in organic nurseries. A review

“…The other group can counteract only one of a few targeted pathogens and includes biocontrol species of Agrobacterium, Ampelomyces, Coniothyrium, non-pathogenic Fusarium, atoxigenic Aspergillus, etc. (Ruocco et al 2015). Currently, there are a limited number of biological control products available on the market with the situation varying from country to country.…”

Plant-Microbe Interactions: A Molecular Approach

“…The release of JA, hence, results in the overexpression of genes encoding proteinase inhibitors and other enzymes involved in the production of volatile oils, phenolics, and alkaloids, all of which play an important role in the biodefense process. These mechanisms have been well characterized in the case of legumes in response to fungal infection by Trichoderma viride (Ruocco et al 2015 ). In this case, cellulysin released by the fungus induces the production and release of JA and downstream volatile compounds (Pushpalatha et al 2013 ) (Fig.…”