Identification of effector-like proteins in Trichoderma spp. and role of a hydrophobin in the plant-fungus interaction and mycoparasitism

Abstract

Background Trichoderma spp. can establish beneficial interactions with plants by promoting plant growth and defense systems, as well as, antagonizing fungal phytopathogens in mycoparasitic interactions. Such interactions depend on signal exchange between both participants and can be mediated by effector proteins that alter the host cell structure and function, allowing the establishment of the relationship. The main purpose of this work was to identify, using computational methods, candidates of effector proteins from T. virens, T. atroviride and T. reesei, validate the expression of some of the genes during a beneficial interaction and mycoparasitism and to define the biological function for one of them.ResultsWe defined a catalogue of putative effector proteins from T. virens, T. atroviride and T. reesei. We further validated the expression of 16 genes encoding putative effector proteins from T. virens and T. atroviride during the interaction with the plant Arabidopsis thaliana, and with two anastomosis groups of the phytopathogenic fungus Rhizoctonia solani. We found genes which transcript levels are modified in response to the presence of both plant fungi, as well as genes that respond only to either a plant or a fungal host. Further, we show that overexpression of the gene tvhydii1, a Class II hydrophobin family member, enhances the antagonistic activity of T. virens against R. solani AG2. Further, deletion of tvhydii1 results in reduced colonization of plant roots, while its overexpression increases it. ConclusionsOur results show that Trichoderma is able to respond in different ways to the presence of a plant or a fungal host, and it can even distinguish between different strains of fungi of a given species. The putative effector proteins identified here may play roles in preventing perception of the fungus by its hosts, favoring host colonization or protecting it from the host’s defense response. Finally, the novel effector protein TVHYDII1 plays a role in plant root colonization by T, virens, and participates in its antagonistic activity against R. solani.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-017-0481-y) contains supplementary material, which is available to authorized users.

Functional Characterization of TvCyt2, a Member of the p450 Monooxygenases From Trichoderma virens Relevant During the Association With Plants and Mycoparasitism

“…During T. virens and A. thaliana interactions, we observed that, even before there was physical contact between both participants, the expression of TvCyt2 was down-regulated, subsequently increasing until reaching the basal expression levels observed in the control condition. This behavior in gene expression has been observed in epl1 and Tatrx2 genes reported by Guzmán-Guzmán et al (2017). Moreover, a transcriptomic analysis of T. atroviride in interactions with A. thaliana showed a larger number of downregulated genes than upregulated genes, suggesting that the presence of the plant provides signals participating in the downregulation of some genes normally expressed in the vegetative state, thus starting a chemical communication that contributes to the establishment of the symbiosis (A. Herrera-Estrella personal communication).…”

Trichoderma Histone Deacetylase HDA-2 Modulates Multiple Responses in Arabidopsis

“…Brotman et al, 2008;Morán-Diez et al, 2009;Salas-Marina et al, 2015). Importantly, some of these MAMPs are also proteins (swollenins, endopolygalacturonases, and hydrophobins) that work as colonization factors (Brotman et al, 2008;Morán-Diez et al, 2009;Guzmán-Guzmán et al, 2017) or help the fungus to tolerate antimicrobial compounds accumulated by the plant (Ruocco et al, 2009). Here, Dhda-2 was affected in its capability to induce the SAR and ISR in Arabidopsis, probably as a consequence of its impairment to colonize Arabidopsis roots, and therefore was unable to induce protection against the biotrophic and necrotrophic pathogens Pst DC3000 and B. cinerea.…”

The inconspicuous gatekeeper: endophytic Serendipita vermifera acts as extended plant protection barrier in the rhizosphere

“…Recently, the Zymoseptoria tritici ribonuclease effector Zt6 was shown to display both phytotoxic as well as antimicrobial activity , providing first experimental evidence for a class of effector proteins required for plant colonisation as well as microbeÀmicrobe interactions. Similarly, the gene tvhydii1 of Trichoderma virens, encoding a class II hydrophobin, is expressed during Arabidopsis thaliana root colonisation as well as confrontation with the phytopathogen Rhizoctonia solani (Guzman-Guzman et al, 2017). Moreover, putative effector genes of the mycoparasite Pseudozyma flocculosa are specifically expressed during colonisation of the phytopathogen Blumeria graminis (Laur et al, 2018).…”