Assessment of microbial antagonistic activity and Quorum Sensing Signal Molecule (Cyclopeptides-DKPs and N-Acyl Homoserine Lactones) detection in bacterial strains obtained from avocado thrips (Thysanoptera: Thripidae)

The control of avocado pests and diseases heavily relies on the use of several types of pesticides, some of which are strictly monitored or not internationally accepted. New sources of bioactive molecules produced by phytopathogen-inhibiting microorganisms offer an excellent alternative for the control of pests and diseases. This study explores the potential antagonistic action against phytopathogenic microorganisms, using bacterial strains obtained from avocado thrips. In addition, we detected and identified quorum sensing (QS) signaling molecules that are related to virulence factors and antibiotic production. The results showed that Bacillus, Pantoea, and Serratia strains exhibited antagonism against five fungal phytopathogens. Additionally, some bacteria also produce specific signaling molecules like N-3-(oxododecanoyl)-l-homoserine lactone (OdDHL), N-(3-oxo)-hexanoyl l-HL (OHHL), 4‑hydroxy-2-heptylquinoline (HHQ) or 2-heptyl-3,4-dihydroxyquinoline (PQS, Pseudomonas quinolone signal), cyclo(L-Phe-l-Pro), and cyclo(L-Pro-l-Tyr, which might give them antimicrobial properties. This research explores the biotechnological potential of these bacteria in fighting the diseases affecting avocados in Colombia.