Bacterial Lipodepsipeptides and Some of Their Derivatives andCyclic Dipeptides as Potential Agents for Biocontrol of PathogenicBacteria and Fungi of Agrarian Plants

Biotic stresses (fungi, bacteria, insects, weeds, etc.) are some of the most important causes of the decrease in thequality and quantity of crops that could become an emergency due to a noteworthy increase in the world population. Thus, toovercome these problems, massive use of chemical pesticides has been carried out with heavy consequences for environmentalpollution and food safety. An eco-friendly alternative can be using natural compound-based biopesticides with high efficacy andselectivity. Some bacterial lipodepsipeptides (tolaasins I, II, A, D, and E and WLIP together with hexacetyl- and tetrahydro-tolaasin Iand WLIP methyl ester) and cyclic dipeptides (cyclo(L-Pro-L-Tyr), cyclo(D-Pro-L-Tyr), cyclo(L-Pro-L-Val), and cyclo(L-Pro-L-Leu))were assayed against several pathogenic bacteria and fungi of important agrarian plants. Lipodepsipeptides showed strong growthinhibition of all microorganisms tested in the range of 0.1-0.8 mu g/mL, while cyclodipeptides, despite preserving this ability, showeda noteworthily reduced antimicrobial activity being active only in the range of 15-900 mu g/mL. Among the lipodepsipeptides andcyclic dipeptides assayed, tolaasinDand cyclo(L-Pro-L-Tyr) (also named maculosin-1) appeared to be the most toxic compounds.Some structure-activity relationships of lipodepsipeptides were also discussed along with their practical application as biopesticidesin agriculture.