Diversity Analysis of Mango Anthracnose Pathogens in the Philippines: Unveiling the Variability and Implications for Disease Management
Robert A. Nepomuceno*, Cristine Marie B. Brown, Mannix S. Pedro, and Marilyn B. Brown
National Institute of Molecular Biology and Biotechnology (BIOTECH), University of the Philippines, Los Baños
Anthracnose refers to a group of diseases that display similar symptoms, such as tissue necrosis and the formation of lesions. In mangoes, this disease remains hidden and only becomes evident during the post-harvest stage, causing the development of sunken gray to black lesions on ripening fruits. To effectively address this disease, it is crucial to conduct a survey and diversity analysis of the pathogen. Therefore, in this investigation, mangoes affected by anthracnose were gathered from twelve provinces, comprising forty-six sampling sites across the Philippine archipelago. The collected isolates were then culturally characterized and subjected to DNA comparison using the internal transcribed spacer (ITS), actin, and chitin. The resulting multilocus phylogenetic analysis produced three distinct clusters representing three separate species: Colletotrichum gloeosporioides, Neofusicoccum mangiferae, and Diaporthe pseudomangiferae. N. mangiferae was identified in more than half of the isolates, suggesting its prevalence as a pathogen. Cultural characterization revealed similar traits among C. gloeosporioides, N. mangiferae, and D. pseudomangiferae, making it easy to mistake them for one another, particularly when relying solely on cultural characteristics for identification. A pathogenicity test demonstrated that both N. mangiferae and C. gloeosporioides could induce lesion formation in mangoes. Although C. gloeosporioides is largely associated with mango anthracnose, this study reveals that N. mangiferae is equally widespread and potent as C. gloeosporioides. The findings of this study highlight the prevalence and potential virulence of Neofusicoccum mangiferae alongside Colletotrichum gloeosporioides. Understanding the diversity and distribution of these pathogens can aid in developing targeted strategies to effectively control and mitigate mango anthracnose in the post-harvest stage.