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

Author: mycolabadmin
6/23/2025
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Summary

Coffee leaf rust is a major disease that destroys coffee crops and costs the global coffee industry billions of dollars annually. Researchers in China discovered that a fungus called Acremonium persicinum naturally parasitizes the rust-causing fungus and can prevent coffee leaves from being infected. When this beneficial fungus was applied to infected coffee leaves, it completely stopped the rust fungus from growing and spreading. This discovery offers farmers an environmentally friendly alternative to chemical pesticides for protecting their coffee crops.

Background

Coffee leaf rust (CLR), caused by Hemileia vastatrix, is one of the most economically devastating plant pathogens in global coffee production, causing yield losses exceeding 70% and annual global losses estimated at 1-2 billion USD. Coffee cultivation in China, particularly in Yunnan Province, is severely threatened by CLR due to progressive erosion of resistance in widely cultivated varieties. Hyperparasites, organisms that parasitize other parasitic organisms, have been identified as potential biological control agents against CLR.

Objective

This study aimed to identify and characterize a hyperparasitic fungal strain isolated from H. vastatrix-infected coffee leaves in Yunnan, China, and evaluate its potential as a biocontrol agent against CLR. The research combined morphological characterization, molecular identification, and pathogenicity evaluation to assess the strain’s efficacy against coffee rust.

Results

Strain HY85 was identified as Acremonium persicinum, the first such identification for coffee rust biocontrol. The spore suspension exhibited a 91.18% inhibition rate against H. vastatrix urediniospore germination. Cross-inoculation experiments showed complete suppression of H. vastatrix infection (chlorotic lesions and urediniospores failed to develop) when coinoculated with HY85. qPCR analysis revealed H. vastatrix DNA was undetectable in coinoculated leaf discs while control inoculations showed copy numbers of 1.41-7.59 × 10⁸. Field experiments demonstrated 66.67% control efficacy, with SEM showing HY85 caused indentation, collapse, and structural damage to rust urediniospores.

Conclusion

Acremonium persicinum strain HY85 demonstrates significant potential as a biocontrol agent against coffee leaf rust through complete suppression of pathogen infection, inhibition of spore germination, and direct destruction of rust spore structures. The findings provide a foundation for developing environmentally sustainable, chemical-free CLR management strategies. Further research into the mechanism of hyperparasitism is needed to optimize its application in coffee production systems.

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