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The citrus crop is one of the most important culture worldwide, being Brazil the world highest producer of sweet oranges. The challenge for this culture is the constant attack by several pathogens that cause economically losses. Among the fungal diseases the post-bloom fruit drop causes dramatically losses in production, characterized by damages in the blossoms that causes fruit infeasibility and early drop, one of the causal agent is Colletotrichum abscissum. The pathogen control is based in chemical applications, irrespective of crops and fungicides used, development of fungicide-resistant pathogen populations is a problem in agriculture. New technologies are being applied every year to better understand the pathogens biology, which can contribute to plant diseases control as an alternative to chemical compounds. The RNA interference emerged as a potential technology for gene function studies as well as an approach for pathogens control. The fungicides compounds have action in different targets, such as the succinate dehydrogenase (SDH), which plays a hole in cell respiration. Therefore, here we investigate the functionality of the RNAi machinery of C. abscissum and test genetically whether the chemically pre-defined fungal SDH target may represent a promising target gene in RNAi based control strategies. The C. abscissum RNAi machinery was functionally proven by silencing of gene report. Then, the silencing of SDH subunits were induced and verified. In addition, the C. abscissum mutants generated for this study made possible the fungus infection process investigation. Furthermore, knockdown mutants of succinate dehydrogenase subunits genes resulted in morphological and significant pathogenicity changes. Thus, in conclusion, we suggest that the RNA interference is an important tool that can be exploited to post bloom fruit drop disease control and also the chemical fungicide target are still useful in the new technologies control strategies., (Copyright © 2021. Published by Elsevier GmbH.)

Background: Recent application of molecular-based technologies has considerably advanced our understanding of complex processes in plant-pathogen interactions and their key components such as PAMPs, PRRs, effectors and R-genes. To develop novel control strategies for disease prevention in citrus, it is essential to expand and consolidate our knowledge of the molecular interaction of citrus plants with their pathogens., Scope: This review provides an overview of our understanding of citrus plant immunity, focusing on the molecular mechanisms involved in the interactions with viruses, bacteria, fungi, oomycetes and vectors related to the following diseases: tristeza, psorosis, citrus variegated chlorosis, citrus canker, huanglongbing, brown spot, post-bloom, anthracnose, gummosis and citrus root rot., (© The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com)