Understanding the chemical warfare and the virulence strategies of Penicillium digitatum involved in the pathogen- host interaction

• Grant number: 22/03594-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): June 01, 2022
• Status: Discontinued
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal Investigator: Roberto Gomes de Souza Berlinck
• Grantee: Evandro Aparecido da Silva
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 19/17721-9 - The role of Chemistry in holobiont adaptation, AP.TEM
• Associated scholarship(s): 23/03831-2 - Deciphering the role of secondary metabolites in the chemical interaction between phytopathogens and the citrus host, BE.EP.PD

Abstract

Citrus is one of the most widely produced fruit globally. Brazil, particularly, is the world's largest citrus producer and exporter of frozen concentrated orange juice and citriculture represents an important percentage of Brazilian economy. However, our citriculture is facing a huge problem, the plant pathogen fungus Penicillium digitatum, which is responsible for the most common and serious postharvest disease that affect citrus worldwide. It is estimated that about 90% of the postharvest losses in Brazil is related to this microorganism. P. digitatum is not the only postharvest pathogen of citrus fruits, Penicillium italicum is also a problem in smaller proportions. Interestingly, P. digitatum and P. italicum show considerable specificity concerning citrus fruits. This very interesting observation intrigued our research group. What would be the chemical mechanisms involved in this very specific interaction? Would the compounds produced by the fungi be important for the interaction and be influencing such behavior? Understanding more about this interaction and the mechanisms that these Penicillium species developed to kill the host, would lead to more efficient and safer alternative strategies to protect them, increasing productivity of our citriculture. We intend to gain insights about these questions identifying the compounds (secondary metabolites) that both fungi produce during the infection in citrus by different chemical techniques. To understand if these compounds have an important role in the interaction, we will develop experiments to generate in the laboratory, a genetic manipulated P. digitatum that do not have the ability to produce a specific class of compounds that we believe to be involved in the infection process. The next step would be to re-infect the citrus fruits with the genetically manipulated organism and check for signs of the disease. The inability of the manipulated organism to infect the citrus fruit or cause weaker symptoms would indicate that the studied compound in very important for the fungus-host plant interaction. Currently, the postharvest control is performed by the mass application of fungicides in fruits. However, continuous use of these fungicides has resulted in fungi with fungicide resistances. In addition, this procedure has serious implications on toxicity, consumer acceptance and environmental risk, such as the persistence of the residues on the treated fruits which impacts directly our alimentation. Therefore, the challenge is to develop safer and eco- friendly alternative strategies of controlling citrus diseases caused by fungi) Brazilian citriculturedesperate needs help to overcome such challenge and our research project would contribute in this direction to our Country. (AU)