The use of siderophores for improving the control of postharvest diseases in stored fruits and vegetables

Abstract

Penicillium expansum and Botrytis cinerea are well-known postharvest pathogens. They produce blue rot and gray rot, respectively. Biocontrol, an alternative to fungicides for the control of these phytopathogens, employs saprophytic microorganisms that protect fruits and vegetables from infection. However, it appears that control of postharvest diseases with antagonistic microorganisms is not often as consistent as control with synthetic fungicides. At this point, microbial metabolites may help improve control of plant pathogens either by enhancing the action of antagonistic microorganisms or by providing tools to develop healthier alternatives than synthetic chemical fungicides. Particularly, the siderophores, ferric chelating agents of low molecular weight, produced by yeasts and bacteria can significantly improve control by antagonistic microorganisms especially if their mechanism of action is the competition for nutrients. Also, the siderophores can interfere with the action of the pathogens because may inhibit enzymes important for their installation in the wounds of post-harvest fruit. Rhodotorulic acid produced by Rhodotorula glutinis and Enterochelin produced by Rahnella aquatilis, siderophores of different chemical nature, can be applied with success in the control of P. expansum and B. cinerea. This chapter describes the production and application of siderophores, and also shows as these metabolites allow the design of new and improved strategies for the control of postharvest pathogens.