Colletotrichum acutatum: conidia dispersal during extreme weather conditions (rain and/or wind) and detection on symptomless leaves by high-resolution melting (HRM) technique

• Grant number: 19/02604-7
• Support type: Scholarships abroad - Research
• Effective date (Start): June 04, 2019
• Effective date (End): September 03, 2019
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Maria Candida de Godoy Gasparoto
• Grantee: Maria Candida de Godoy Gasparoto
• Host: Natalia Aparecida Peres Lauretti
• Home Institution: Universidade Estadual Paulista (UNESP). Campus de Registro. Registro , SP, Brazil
• Local de pesquisa : University of Florida, Gainesville (UF), United States

Abstract

Colletotrichum acutatum sensu lato is the causal agent of citrus postbloom fruit drop (PFD) and anthracnose fruit rot (AFR). Conidia from acervuli on infected flowers (citrus and strawberry) and fruit (strawberry), and spores from appressoria on the leaves (citrus and strawberry) are the inoculum sources of the diseases. Rainfall is essential to disperse pathogen spores, and long wetness periods must occur to cause important epidemics. In Brazil and mainly in the USA, it is common the occurrence of stronger winds when conditions are favorable for PFD and AFR. No studies have been carried out to evaluate pathogen dispersal during extreme weather conditions. Besides this, it is important to develop an efficient method to detect C. acutatum on symptomless citrus leaves to confirm if there is pathogen dissemination from citrus nurseries to new groves, as reported in strawberry nurseries. Our objective are: (i) to investigate whether different combinations of wind and simulated rainfall can successfully remove and spread conidia from citrus and strawberry leaf surfaces and how far these spores can reach from the source of inoculum;(ii) to study whether the dispersal pattern changes when conidia produced on acervuli on fruit and flowers are exposed to different combinations of rainfall and wind; (iii) to adapt, develop, and test a high-throughput method for detection of citrus-pathogenic C. acutatum on symptomless leaves. This would be the first study to comprehensively asses the dispersal of C. acutatum sensu lato at different simulated weather conditions and to test high-resolution melting as a detection for citrus-pathogenic C. acutatum.