# Diversity of Trichoderma in the unexplored Bolivian Amazon region and their potential for coffee diseases control

## TL;DR

This study explores Trichoderma fungi in Bolivian Amazon soils and finds potential biocontrol agents for coffee diseases.

## Contribution

It is the first comprehensive study of Trichoderma diversity in the Yungas region and identifies new species with biocontrol potential.

## Key findings

- Trichoderma diversity is influenced by ecosystem type and altitude.
- 70 isolates showed strong antagonism against coffee wilt pathogen Fusarium oxysporum.
- 41 isolates represent previously unrecognized Trichoderma species.

## Abstract

Trichoderma fungi are colonizers of plant substrates and rhizosphere and are valued for their antagonism against phytopathogens and ability to promote plant health. We investigated Trichoderma diversity in coffee-growing soils in Caranavi region of Yungas-La Paz, Bolivia, where high humidity and fungal diseases threaten yield, and evaluated their potential as biocontrol agents against coffee pathogens. A total of 440 Trichoderma were isolated from coffee rhizosphere, fallow lands, and forest ecosystems across an altitudinal gradient in Caranavi. DNA barcode analyses using ITS, rpb2, and tef1 loci identified only four species. However, 47 taxa comprising 344 isolates were ambiguous, and 41 isolates were previously unrecognised species. The diversity of Trichoderma spp. was significantly affected by ecosystem type and altitude, with more species isolated from coffee rhizosphere than fallow lands and forest ecosystems, and from lower altitudes than higher ones. Evaluation of 100 isolates against a native coffee wilt pathogen Fusarium oxysporum identified 70 potent antagonists, with 30 achieving 90–100% disease control. This is the first comprehensive study of Trichoderma diversity in Yungas, identifying indigenous Trichoderma for biocontrol applications against coffee diseases. It also emphasizes the need to refine the Trichoderma species concept and improve the taxonomic resolution within the genus.

An investigation of Trichoderma diversity in the unexplored Amazonic region of Bolivia highlights the importance of refining the Trichoderma species concept and improving taxonomic resolution within the genus.