Identification and potential of the hyperparasite Acremonium persicinum as biocontrol agent against coffee leaf rust

Author: mycolabadmin
6/23/2025
View Source

Summary

Coffee plants are severely damaged by a fungal disease called coffee leaf rust that destroys leaves and can reduce harvests by over 70%. Scientists in China discovered a beneficial fungus called Acremonium persicinum that acts as a natural enemy to the rust-causing fungus, essentially eating and destroying it. Laboratory tests showed this beneficial fungus prevented rust infection in 91% of cases and completely stopped the disease from spreading when applied to infected coffee leaves. This natural biological control offers an environmentally friendly alternative to chemical pesticides for protecting coffee crops.

Background

Coffee leaf rust (CLR) caused by Hemileia vastatrix is a major threat to global coffee production, causing yield losses exceeding 70% in some regions and inflicting annual global losses of 1-2 billion US dollars. Hyperparasites that parasitize pathogenic fungi offer promising biological control alternatives to chemical fungicides. This study focuses on identifying and evaluating hyperparasitic fungi isolated from CLR-infected coffee leaves in Yunnan, China.

Objective

This study aimed to identify the hyperparasitic fungal strain HY85 and evaluate its potential as a biological control agent against coffee leaf rust caused by H. vastatrix. The research characterized the fungus morphologically and molecularly, assessed its inhibitory effects on rust spore germination and infection, and quantified its impact on pathogen biomass.

Results

Molecular analysis identified strain HY85 as Acremonium persicinum with 97.75% ITS and 99.33% LSU similarity to reference strains. The HY85 spore suspension achieved a 91.18% inhibition rate of H. vastatrix urediniospore germination. Cross-inoculation experiments showed complete suppression of pathogen infection and development regardless of inoculation order, with qPCR analysis detecting no H. vastatrix DNA in coinoculated leaf discs while single-inoculated controls showed 1.41-7.59 × 10⁸ copies. Control efficacy against naturally occurring rust lesions reached 66.67%, with SEM revealing severe morphological damage to urediniospores.

Conclusion

Acremonium persicinum strain HY85 represents the first identified hyperparasitic control agent of coffee leaf rust and demonstrates significant potential as a biocontrol agent. The strain exhibits multiple inhibitory mechanisms including suppression of spore germination, direct parasitism of urediniospores, and complete prevention of pathogen establishment. These findings provide a foundation for developing environmentally sustainable biological control strategies for coffee rust management.

Published in:FEMS Microbiology Ecology,
Study Type:Experimental Research,
Source: 10.1093/femsec/fiaf064, PMID: 40581491