Control of postharvest fungal diseases in fruits using external application of RNAi

Abstract

Contamination with a variety of filamentous fungi can cause deterioration of food and agricultural products. Fungal contaminations reduce the quality and the shelf life of fresh fruits and are one of the main causes of economic loss in the global fresh fruit industry. Although chemical fungicides are effective and traditionally used to control postharvest fungal diseases, they are harmful to human health. In this context, use of RNA interference (RNAi)-based fungicides is a promising alternative strategy. Spray-induced gene silencing (SIGS) is an innovative RNAi-based approach for silencing target genes in phytopathogens. This review aims to discuss the recent findings on the use of RNAi-based fungicides to control the postharvest spoilage of fresh fruits. Practical Application: Control of postharvest fungal diseases is one of the most important strategies to make food available to consumers longer. In this sense, the external application of RNAi seems to be technologically advantageous and efficient as it helps to maintain the characteristics of plant products. In this sense, this review discussed what is possible to find in the literature regarding this new technology.

Management of Post-Harvest Anthracnose: Current Approaches and Future Perspectives

“…With respect to fruit infection, the early stages of the interaction with host tissues are similar for all the Colletotrichum species [ 7 ]: conidiospores spread from infected vegetal material or through insects, adhere by means of a hemicellulosic mucilage to the external vegetal surface, germinate and infect often by mean of specialized structures, such as appressoria [ 8 , 9 , 10 , 11 ]. Infections can take place even by penetration through stomata, lenticels, wounds, or abscission of scar tissue [ 11 , 12 , 13 , 14 , 15 ].…”

“…With respect to fruit infection, the early stages of the interaction with host tissues are similar for all the Colletotrichum species [ 7 ]: conidiospores spread from infected vegetal material or through insects, adhere by means of a hemicellulosic mucilage to the external vegetal surface, germinate and infect often by mean of specialized structures, such as appressoria [ 8 , 9 , 10 , 11 ]. Infections can take place even by penetration through stomata, lenticels, wounds, or abscission of scar tissue [ 11 , 12 , 13 , 14 , 15 ]. Although specific host–pathogen interaction and infection strategies have been detected, such as in C. acutatum sensu lato that exhibit four different colonization pathways [ 16 ], the process proceeds according to two main strategies, depending on the different species, hosts, and tissues: (i) intracellular hemibiotrophy or (ii) subcuticular, intramural necrotrophy [ 6 , 7 , 17 , 18 ].…”

“…Anthracnose symptoms highly vary depending on the plant tissue and cause huge losses of fruit production [ 11 ]. For instance, strawberry plants, which are susceptible to several Colletotrichum species, can exhibit serious anthracnose symptoms in all its parts [ 30 , 31 ].…”

“…In general, symptoms on stems or leaves range from small greyish-brown sunken spots to darker patches on branches. On the contrary, infected blossoms appear dry and rotten with compromised fruit development, whereas on fruits anthracnose produce dark lesions surrounding pink or orange conidia masses that under suitable conditions can evolve causing tissue necrosis [ 4 , 11 , 34 , 35 , 36 ]. In any case, the highest impact of this disease is due to the fruit damage during postharvest storage ( Figure 1 ).…”

“…Post-harvest anthracnose is mainly due to infections taking place in the field that become quiescent until the occurrence of conditions favorable for pathogen germination and development [ 37 , 41 , 42 ]. As a result, the disease is particularly severe for climacteric fruits such as banana, guava, avocado, pear, mango, and papaya since their ripening stage includes physiological and biochemical changes, due to the re-modelling and degradation of cell walls, providing suitable conditions for the fungal development [ 11 , 43 , 44 ]. Nevertheless, anthracnose represents a serious constrain even for non-climateric fruits, such as strawberry, citrus, and dragon fruit [ 3 , 45 , 46 , 47 ].…”