RNA interference in Colletotrichum abscissum, causal agent of citrus postbloom fruit drop

Citrus is an economically important culture for many countries worldwide, being Brazil the world highest producer of sweet oranges and orange juice. The great concern for this culture is the severe incidence of several pathogens causing relevant economically losses. Among the fungal diseases post-bloom fruit drop (PFD) causes dramatically losses in production, it is characterized by damages in the blossoms that causes fruit infeasibility and early drop, the Colletotrichum abscissum is one of the causal agent. The control of this pathogen is based in chemical spraying that contribute to the resistance development over the time. Fungicides compounds have action in different targets, as the succinate dehydrogenase, which plays a hole in the tricarboxylic acid cycle and also in mitochondrial electron transport chain, making this enzyme a target to several fungicides. New technologies are being applied every year to better understand the pathogens biology, and it can contribute to plant diseases control as an alternative to chemical control. The RNA interference emerge as a potential technology for gene function studies as well as an approach for pathogens control. Here we investigate the presence and functionality of the RNAi machinery of C. abscissum and test genetically whether the chemically pre-defined fungal SDHi target may represent a promising target gene in HIGS plants. In addition, the mutants generated for this studies made possible the fungus infection process investigation. Furthermore, knockdown mutants of succinate dehydrogenase subunit gene resulted in morphological and pathogenicity changes. Therefore, we concluded that the RNA interference is an important tool that can be exploited to disease control.

Support: Fapesp (Processo: 2012/23381-7) and INCT Citros (Processo Fapesp: 2014/50880-0 and CNPq: 465440/2014-2)