Evaluación de quitosano comercial y extractos acuosos de mesocarpio de coco (Cocos nucifera L.) para el control de Rhizopus stolonifer aislado de guanábana (Annona muricata L.): Pruebas in vitro

Abstract

La eficacia antifúngica de los extractos acuosos de mesocarpio de coco (Cocos nucifera L.) (EAC) y el quitosano comercial (QC) aplicados de manera individual y en combinación se evaluó contra Rhizopus stolonifer en términos de crecimiento micelial, esporulación y germinación de las esporas, así como la obtención de los modelos de crecimiento primario en dos temperaturas de almacenamiento (15-25 ºC). La aplicación de los EAC al 10% redujo significativamente el crecimiento micelial de R. stolonifer (58.81 ± 6.48%); por otro lado, el QC (1.5%) mostró un efecto de control de hasta un 87%, sin embargo, la combinación de los EAC (10%) con el QC (1.5%) fue más efectiva al reducir el crecimiento micelial (> 93 %). Todos los tratamientos fueron efectivos para disminuir la producción de esporas (> 94 %) en comparación con el control (agar). El QC al combinarse con los EAC fue más efectivo inhibiendola elongación del tubo germinal (> 98 %) comparado con los tratamientos individuales (< 48 %). El modelo modificado de Gompertz mostró un ajuste adecuado para ambos rangos de temperatura (> 98-99 %) observándose diferencias significativas (p ≤ 0.05) entre las variables de velocidad máxima (Vmáx) y periodo de latencia (ƛ), no obstante, todos los tratamientos mostraron un efecto fungistático sobre el desarrollo micelial de R. stolonifer. La combinación de los EAC y el QC puede ser una alternativa eco-amigable contra la pudrición suave de los frutos de guanábana.

Coconut Mesocarp Extracts to Control Fusarium musae, the Causal Agent of Banana Fruit and Crown Rot

“…The sporulation process of the genus Fusarium plays a key role in the disease cycle through spores, and in this sense, wounds caused by cutting off the hands after harvest are the point of access of spores to the crown; with favorable conditions, the spore can germinate, infect the fruit tissues, and induce necrosis and detachment of the fruit [36,37]. The in vitro results of this research are in agreement with the report by Cortés-Rivera et al [17] against the blue mold agent in citrus and Rhizopus stolonifer, the soft rot agent in soursop [38]. The differences in the efficacy of treatments depending on the fruit tissue could be related not only to the nutrient composition of tissues [39] but also to the affectation of fungus due to the extract exposition in tissues, playing a key role in the fungus development as evidenced by SEM (Figure 7b,d).…”

Chitosan in the protection of agricultural crops against phytopathogens agents

“…28,35,46 In addition, chitosan is a bio-stimulant of growth-promoting microorganisms of the type: Trichoderma spp., 29 such as genera and species of mycorrhizal fungi 47 of actinomycetes: Streptomyces, Kitasatospora, since they synthesize chitosanases that hydrolyze chitosan to use it as a carbon and nitrogen source. 48 While chitosan is compatible with other plant products such as botanical extracts 12 and carbon nanoparticles, 49 with antagonistic activity.…”

“…28 It is reported that chitosan interferes with the transformation of DNA into RNA, prevents cell growth, as well as the synthesis of proteins linked to carbohydrates, affects the genetic regulation of chitin synthesis in the cell wall. 28,52,60 In the microbial spores, it causes disorganization of the cytoplasm with loss of intracellular content, affects the spore membrane, 52 due to the relationship of the amino groups of chitosan that interact with the negative charge of the cell membrane of the spore and inhibits germination 12 In the mycelium, the loss of nutrients causes vacuolation, with the formation of thin, distorted, and malformed hyphae. 53 In the genera and species of Gram negative (-) bacteria, chitosan is attracted by electrostatic attractions, with lipopolysaccharides of the outer membrane, and affects permeability.…”

“…4,5 Environmentally, other control methods are of value, in harmony with agroecosystems, soil biodiversity and human health without resistance in phytopathogens. Research indicates that one of the best alternatives to control phytopathogens is with antagonistic microorganisms, 6,9,11 botanical extracts 12 and others with antifungal properties such as chitosan [12][13][14] with results positive in the natural control of phytopathogens.…”

Integrated system for paclitaxel production from endophytic fungus, Neopestalotiopsis clavispora ASU1 and subsequent extraction of chitosan from fungal biomass wastes

“…Chitosan was extracted from different fungal species such as, Cunninghamella elegans (0.75 g l -1 ), C. blakesleeana (9.4 % of fungal biomass), Rhizomucor miehei (13.67 %), Mucor rouxii (1.2 %) Cladosporium Cladosporioides (25.2 mg/g) with degree of deacetylation 81 %, 35 %, 80.6 % and 59 %, respectively (George et al, 2011;Miyoshi et al, 1992;Tajdini et al, 2010;Tayel et al, 2016). As well as the extracted chitosan of some fungi was tested for their biotechnological applications in water pollutant elimination (heavy metals and waterborne microorganisms) and removal of toxic pollutants biocontrol of postharvest diseases (Betchem, et al, 2019;Cortés-Rivera et al, 2021) ). Furthermore, these results provide a promising approach for concomitant production of paclitaxel and chitosan sources and increase the possibility for production and extraction of fungal chitosan with well-defined properties at an industrial scale.…”