# Enhanced resistance to heat and fungal infection in transgenic Trichoderma via over-expressing the HSP70 gene

## TL;DR

This study shows that overexpressing the HSP70 gene in Trichoderma improves its resistance to heat and fungal infections.

## Contribution

The study identifies and experimentally validates the role of HSP70 in enhancing Trichoderma's stress resistance through transcriptomic and functional analyses.

## Key findings

- Overexpression of HSP70 in Trichoderma enhances growth, antioxidant capacity, and antifungal activity.
- HSP70 activates genes involved in antibiotic synthesis and stress response pathways.
- Transcriptomic analysis reveals HSP70's role in regulating secondary metabolite biosynthesis under heat stress.

## Abstract

Heat stress is one of the major abiotic stresses affecting the growth, sporulation, colonization and survival of Trichoderma viride. This study aimed to gain a better insight into the underlying mechanism governing the heat stress response of T. viride Tv-1511. We analysed the transcriptomic changes of Tv-1511 under normal and heat stress conditions using RNA sequencing. We observed that Tv-1511 regulates the biosynthesis of secondary metabolites through a complex network of signalling pathways. Additionally, it significantly activates the anti-oxidant defence system, heat shock proteins and stress-response-related transcription factors in response to heat stress. TvHSP70 was identified as a key gene, and transgenic Tv-1511 overexpressing TvHSP70 (TvHSP70-OE) was generated. We conducted an integrated morphological, physiological and molecular analyses of the TvHSP70-OE and wild-type strains. We observed that TvHSP70 over-expression significantly triggered the growth, anti-oxidant capacity, anti-fungal activity and growth-promoting ability of Tv-1511. Regarding anti-oxidant capacity, TvHSP70 primarily up-regulated genes involved in enzymatic and non-enzymatic anti-oxidant systems. In terms of anti-fungal activity, TvHSP70 primarily activated genes involved in the synthesis of enediyne, anti-fungal and aminoglycoside antibiotics. This study provides a comparative analysis of the functional significance and molecular mechanisms of HSP70 in Trichoderma. These findings provide a valuable foundation for further analyses.

The online version contains supplementary material available at 10.1186/s13568-024-01693-5.

Transcriptome analyses reveal the heat resistance mechanism of Trichoderma.

HSP70 overexpression enhances growth-promoting ability and anti-oxidant capacities.

HSP70 promotes anti-fungal resistance by up-regulating antibiotic synthesis genes.

The online version contains supplementary material available at 10.1186/s13568-024-01693-5.