Background and objective: Postharvest disease caused by Colletotrichum spp. caused major losses. The species of Colletotrichum are difficult to distinguish if only seen from their morphology. This study investigated Colletotrichum isolates associated with tropical fruits anthracnose using multi-genetic analysis and the cross-infection potency of each isolate among tropical fruits.
Materials and methods: The fruit samples were collected from markets in the Special Region of Yogyakarta, Indonesia and its surrounding area. The fruits affected by anthracnose subjected to isolation, resulting in 15 isolates. Morphology of colony and conidia then characterized and clustered with UPGMA. The seven representative isolates were selected for molecular identification. The multi-genetic analysis was used by combining ITS, Glyceraldehyde 3-phosphate dehydrogenase (gapdh) and tub2 sequence genes. A cross-infection test was conducted by using selected species from the multi-genetic analysis.
Results: Multi-genetic analysis clustered the selected isolates into four species. Isolates from banana, avocado, papaya and citrus belonged to gloeosporioides species complex, including C. siamense, C. asianum and C. gloeosporioides. Isolates from apple, guava, mango and citrus belonged to acutatum species complex, including C. sloanei. The cross-infection test in this study showed that C. siamense could cause anthracnose on banana, apple, citrus and avocado, C. asianum on avocado, papaya, apple and citrus, C. gloeosporioides on citrus and apple, C. sloanei on apple, guava, citrus and papaya.
Conclusion: The C. siamense, C. asianum, C. gloeosporioides and C. sloanei found associated with tropical fruits anthracnose. The potency of the cross-infection test revealed the board range in the pathogenicity of the Colletotrichum isolates.
Keywords: Colletotrichum spp.; ITS; disease management; fruit anthracnose; gapdh; multi-genetic analysis; postharvest diseases; tub2.