Effect of endogenous earthworm's extracts on "plant growth-promoting fungi"

Abstract

This study explores the in vitro effects of earthworm-derived crude extracts on the growth of key Plant Growth-Promoting Fungi (PGPF) strains, including Trichoderma sp., Melanocarpus sp., and Acaulospora sp. Crude extracts were prepared from freshly harvested earthworms (HE) and those that had been starved and devoid of soil for 10 days (FE), and their effects on fungal proliferation were assessed at varying concentrations. Results demonstrated that both HE and FE extracts significantly enhanced fungal growth rates compared to traditional growth media (PDA and SAB), even at lower concentrations. The enriched nutrient profile and growth factors present in these extracts suggest that earthworm decomposition contributes valuable bioactive compounds to the soil, promoting PGPF activity and soil fertility. Additionally, media derived from these extracts stimulated rapid spore germination, which is critical for fungal dissemination and ecological establishment. Notably, the study found that contents within the earthworm digestive tract did not influence fungal growth, affirming that the growth-promoting effects are inherent to the earthworm tissue structure itself. These findings underscore the potential of earthworm-based media as a natural and effective growth medium for enhancing PGPF propagation, with implications for sustainable agricultural practices and soil health improvement.