Colletotrichum species causing anthracnose on avocado fruit in Mexico: Current status

Abstract

Colletotrichum species cause anthracnose disease in tropical and subtropical fruit crops worldwide. Mexico is the main producer and exporter of avocado (Persea americana) globally and has yearly outbreaks of anthracnose on this crop. However, which specific Colletotrichum spp. cause these outbreaks in avocado‐producing regions remain uncertain; thus, the objective of the present study was to identify the species responsible. A survey performed in six production regions of Mexico yielded 232 isolates, from which a subset of 104 strains was selected based on morphological characteristics and origin. This subset was sequenced and haplotypes were analysed in the gapdh partial gene. Finally, 31 strains were identified through multilocus phylogenetic analyses using the sequences of the internal transcribed spacer region and six loci. This study revealed the presence of two species previously reported in Mexico (C. karsti and C. godetiae), three novel records in Mexico (C. siamense, C. fioriniae, and C. cigarro), four novel records on avocado (C. chrysophilum, C. jiangxiense, C. tropicale, and C. nymphaeae), and two novel lineages (Colletotrichum sp. 1 and Colletotrichum sp. 2). C. siamense was the most prevalent, while the species reported for the first time on avocado, including the novel lineages, were the least prevalent. C. karsti was the most widespread (four regions), followed by C. siamense, C. jiangxiense, and C. chrysophilum (three regions). Pathogenicity tests showed that all species caused anthracnose on avocado fruit. These findings will be useful for improving the management of avocado anthracnose outbreaks in Mexico.

Diversity of Colletotrichum Species Associated with Anthracnose Disease in Tropical Fruit Crops—A Review

“…Another comprehensive study on pathogen of avocado anthracnose was performed by Fuentes-Aragón et al (2020) [96]. Using six markers (GAPDH, ITS, ACT, CHS-1, ApMat and β-tubulin), the study indicated 11 species were the causal pathogens of avocado anthracnose in Mexico, namely C. karstii, C. godetiae, C. siamense, C. fioriniae, C. cigarro, C. chrysophilum, C. jiangxiense, C. tropicale, C. nymphaeae), and two new lineages designated as Colletotrichum sp.…”

First Record of Colletotrichum anthrisci Causing Anthracnose on Avocado Fruits in Chile

“…Over 20 species of Colletotrichum have been reported as causal agents of avocado anthracnose worldwide. Different studies suggest a predominance of species belonging to the gloeosporioides species complex, followed by members of the acutatum and boninense complexes [ 13 , 14 , 15 , 17 ]. Similarly, C. gigasporum and an undescribed species of the magnum complex represent unique detections in Sri Lanka and Mexico, respectively [ 12 , 15 ].…”

“…The causal agents of avocado anthracnose are fungi of the genus Colletotrichum [ 11 ], and approximately 20 species have been reported worldwide, comprising members of five different species complexes, namely gloeosporioides, acutatum, boninense, gigasporum, and magnum [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. In Chile, however, only C. gloeosporioides sensu lato has been reported [ 18 ], which produces orange-colored sporulating lesions.…”

Pest categorisation of Colletotrichum fructicola

“…Plants infected by C. fructicola show symptoms of anthracose, which include dark brown stem and fruit spots, pre‐ and post‐harvest fruit rot, spotting and wilting of leaves (Zhang et al., 2015 ; Guarnaccia et al., 2016 ; Carraro et al., 2019 ; Fu et al., 2019 ; Chung et al., 2020 ; Echeverrigaray et al., 2020 ; Fuentes‐Aragón et al., 2020 ). However, these symptoms are similar to those caused by other Colletotrichum species.…”