This review deals with the main mechanisms of action exerted by antagonistic bacteria, such as competition for space and nutrients, suppression via siderophores, hydrolytic enzymes, antibiosis, biofilm formation, and induction of plant resistance. These mechanisms inhibit phytopathogen growth that affects postharvest fruit since quality and safety parameters are influenced by the action of these microorganisms, which cause production losses in more than 50% of fruit tree species. The use of synthetic fungicide products has been the dominant control strategy for diseases caused by fungi. However, their excessive and inappropriate use in intensive agriculture has brought about problems that have led to environmental contamination, considerable residues in agricultural products, and phytopathogen resistance. Thus, there is a need to generate alternatives that are safe, ecological, and economically viable to face this problem. Phytopathogen inhibition in fruit utilizing antagonist microorganisms has been recognized as a type of biological control (BC), which could represent a viable and environmentally safe alternative to synthetic fungicides. Despite the ecological benefit that derives from the use of controllers and biological control agents (BCA) at a commercial level, their application and efficient use has been minimal at a global level.

Some synthetic fungicides have been currently prohibited due to their adverse effects; thus, searching for alternatives to decrease their application is a priority worldwide. An alternative to the application of synthetic fungicides is chitosan -a natural biopolymer- because of its biocompatibility, biodegradability, and bioactivity. Chitosan has been used in different industries, such as cosmetology, pharmaceutics, food, among others. In agriculture, it has been used as a resistance inductor and bio-fungicide because of its antimicrobial activity and for plant development as growth promoter. Although many works have been published on chitosan for its characteristics and mode of action, the direct effects on agriculture -both in plant and fruit phytopathogens- have not been reported. Therefore, the objective of this review is to summarize recent advances and achievements of chitosan application in agriculture with special attention to its antimicrobial properties and plant defence induction mechanisms.

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La albahaca (Ocimum basilicum L.) es una especie que presenta variabilidad en la tolerancia a distintos tipos de estrés abiótico y se considera una planta sensible a la salinidad en las etapas iniciales de su crecimiento. El objetivo del presente estudio fue determinar el efecto de la salinidad en la germinación de albahaca. Veinte variedades se sometieron a tres concentraciones de NaCl (0, 50 y 100 mM) en un diseño completamente al azar con cuatro repeticiones. El trabajo se desarrolló en cámara de germinación. Las variables que se midieron fueron tasa y porcentaje de germinación, longitud de radícula, altura de plántula, biomasa fresca y seca de radícula y parte aérea. Los resultados evidenciaron que las variedades Sweet Dani, Red Rubin, Genovese Italian, Mrs Burns, Cinnamon, Emily y Dolly tuvieron una mejor respuesta en las variables germinación, tasa de germinación, longitud de radícula, altura de plántula, biomasa fresca y seca de radícula y parte aérea. Se discute la respuesta diferencial entre las variedades al someterlas a diferentes niveles de NaCl.