Microbe-induced gene silencing of fungal gene confers efficient resistance against Fusarium graminearum in maize

Summary

Scientists developed a new method called microbe-induced gene silencing (MIGS) to protect maize crops from a destructive fungus called Fusarium graminearum, which causes stalk rot. They engineered a beneficial fungus (Trichoderma harzianum) to produce small RNA molecules that target and disable a critical gene in the pathogenic fungus, weakening its ability to infect plants. When maize seedlings were grown with this engineered beneficial fungus, they showed significantly better growth and reduced fungal infection compared to untreated plants. This approach offers an environmentally friendly alternative to chemical pesticides and does not require genetically modifying the crop itself.

Background

Fusarium graminearum is a major pathogen causing maize stalk rot worldwide. Traditional breeding approaches are limited by lack of resistance genes. RNA interference (RNAi) offers a promising alternative through microbe-induced gene silencing (MIGS), where engineered microbes produce small RNAs to silence pathogenic fungal genes.

Objective

To develop and evaluate a MIGS technology using an RNAi-engineered Trichoderma harzianum strain to protect maize against Fusarium graminearum by targeting the FgPTM2 gene.

Results

The engineered Th-FgPmt2i strain successfully silenced the FgPMT2 gene via translational inhibition, increasing fungal susceptibility to cell wall-damaging agents. Maize seedlings protected by Th-FgPmt2i showed significantly better growth and reduced fungal biomass compared to untreated controls. The engineered strain provided superior protection compared to wild-type T. harzianum.

Conclusion

MIGS technology effectively protects maize against F. graminearum without requiring host genetic modification. The findings demonstrate that MIGS has broad applicability for protecting various crops against distinct fungal pathogens and represents an environmentally friendly alternative to chemical pesticides.
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