Bacterial non-ribosomal peptides: a sustainable approach for combatting phytopathogenic fungi in agriculture

Plant diseases are the major threats to sustainable agriculture, leading to yearly yield losses. Several phytopathogens such as fungi, bacteria and viruses are known to cause plant diseases that affect agricultural production. To overcome this, the use of toxic chemicals has increased, raising public concern due to their negative impacts on human health and the environment. An alternative to chemicals is the application of biological agents, which may include various bioactive compounds from microbes. Bacterial species' non-ribosomal peptides (NRPs) are becoming promising alternatives to synthetic fungicides due to their antifungal activities. NRPs are small peptides usually containing special amino acids and other organic acids and are biosynthesised by non-ribosomal peptide synthetases (NRPSs). NRPs are used to control phytopathogens in fields. In this review, we highlighted the NRPs' mechanisms of action against key fungal pathogens like Fusarium, Alternaria, and Botrytis. These mechanisms include disrupting cell membrane integrity, interfering with cell wall synthesis, and inhibiting essential cellular processes. We have also addressed various methods for utilising NRPs in agriculture for enhanced production, and formulation into biocontrol agents. Overall, NRPs offer significant potential to enhance crop resilience and reduce losses from fungal diseases, aligning with sustainable agriculture practices. However, further research and collaboration are needed to fully realise their potential in agricultural systems.