Increased activity of the sterol branch of the mevalonate pathway elevates glycosylation of secretory proteins and improves antifungal properties of Trichoderma atroviride

https://doi.org/10.1016/j.fgb.2020.103334Get rights and content
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Highlights

  • Selective activation of squalene synthase by excess of farnesyl pyrophosphate.

  • Interdependence between the mevalonate pathway activity and protein glycosylation.

  • Activation of secretory hydrolases by balanced hyper-glycosylation.

  • Activation of the mevalonate pathway enhancing antifungal activity of Trichoderma.

Abstract

Some Trichoderma spp. have an ability to inhibit proliferation of fungal plant pathogens in the soil. Numerous compounds with a proven antifungal activity are synthesized via the terpene pathway.

Here, we stimulated the activity of the mevalonate pathway in T. atroviride P1 by expressing the Saccharomyces cerevisiae ERG20 gene coding for farnesyl pyrophosphate (FPP) synthase, a key enzyme of this pathway. ERG20-expressing Trichoderma strains showed higher activities of FPP synthase and squalene synthase, the principal recipient of FPP in the mevalonate pathway.

We also observed activation of dolichyl phosphate mannose (DPM) synthase, an enzyme in protein glycosylation, and significantly increased O- and N-glycosylation of secreted proteins. The hyper-glycosylation of secretory hydrolases could explain their increased activity observed in the ERG20 transformants.

Analysis of the antifungal properties of the new strains revealed that the hydrolases secreted by the transformants inhibited growth of a plant pathogen, Pythium ultimum more efficiently compared to the control strain. Consequently, the biocontrol activity of the transgenic strains, determined as their ability to protect bean seeds and seedlings against harmful action of P. ultimum, was also improved substantially.

Keywords

Trichoderma
Antifungal activity
Yeast ERG20 gene
FPP synthase
Squalene synthase

Cited by (0)

1

These authors contributed equally

2

Jacek Lenart had passed away.