Carla Sant Anna Freitas, Lucas Ferreira Maciel, Renato Augusto Corrêa dos Santos, Ohanna Maria Menezes Madeiro Costa, Francisco Carlos Barbosa Maia, Renata Santos Rabelo, Henrique Coutinho Junqueira Franco, Eduardo Alves, Sílvio Roberto Consonni, Raul Oliveira Freitas, Gabriela Felix Persinoti, Juliana Velasco de Castro Oliveira.

Environmental Micobiology J.; First published: 07 January 2022. Volume 24(3): 1430-1453

https://doi.org/10.1111/1462-2920.15876

Summary

Due to an increasing demand for sustainable agricultural practices, the adoption of microbial volatile organic compounds (VOCs) as antagonists against phytopathogens has emerged as an eco-friendly alternative to the use of agrochemicals. Here, we identified three Pseudomonas strains that were able to inhibit, in vitro, up to 80% of mycelial growth of the phytopathogenic fungus Thielaviopsis ethacetica, the causal agent of pineapple sett rot disease in sugarcane. Using GC/MS, we found that these bacteria produced 62 different VOCs, and further functional validation revealed compounds with high antagonistic activity to T. ethacetica. Transcriptomic analysis of the fungal response to VOCs indicated that these metabolites downregulated genes related to fungal central metabolism, such as those involved in carbohydrate metabolism. Interestingly, genes related to the DNA damage response were upregulated, and micro-FTIR analysis corroborated our hypothesis that VOCs triggered DNA damage. Electron microscopy analysis showed critical morphological changes in mycelia treated with VOCs. Altogether, these results indicated that VOCs hampered fungal growth and could lead to cell death. This study represents the first demonstration of the molecular mechanisms involved in the antagonism of sugarcane phytopathogens by VOCs and reinforces that VOCs can be a sustainable alternative for use in phytopathogen biocontrol.

See: https://sfamjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1462-2920.15876