Use of Telomere Fingerprinting to Identify Clonal Lineages ofColletotrichum fioriniaein Kentucky Mixed-Fruit Orchards

Abstract

Multiple species in the fungal genus Colletotrichum cause anthracnose fruit rot diseases that are responsible for major yield losses of as much as 100%. Individual species of Colletotrichum typically have broad host ranges and can infect multiple fruit species. Colletotrichum fioriniae causes anthracnose fruit rots of apples, blueberries and strawberries in Kentucky orchards where these fruits grow in close proximity. This raises the possibility of cross-infection, which may have significant management implications. The potential occurrence of cross-infection was investigated by using telomere fingerprinting to identify C. fioriniae clones in several mixed-fruit orchards. Telomere fingerprints were highly polymorphic among a test group of C. fioriniae strains and effectively defined clonal lineages. Fingerprints were compared among apple, blueberry and strawberry isolates of C. fioriniae from three different orchards and similarity matrices were calculated to build phylograms for each orchard group. Multiple clonal lineages of C. fioriniae were identified within each orchard on the same fruit host. Related lineages were found among isolates from different hosts, but the results did not provide direct evidence for cross-infection of different fruit species by the same clones. Recovery of the same clonal lineages within orchards across multiple years suggested that local dispersal was important in pathogen population structure and that C. fioriniae strains persisted within orchards over time. Isolates from blueberry were less diverse than isolates from apple, perhaps related to more intensive anthracnose management protocols on apple versus blueberry. Telomere fingerprinting is a valuable tool for understanding population dynamics of Colletotrichum fruit rot fungi.

Attack of the clones: Population genetics reveals clonality of Colletotrichum lupini, the causal agent of lupin anthracnose

“…Examples of single genotypes causing significant crop losses are the broad host range Verticillium dahliae (Milgroom et al, 2016), F. oxysporum on banana (Ordonez et al, 2015), and Phytophthora infestans on potato (Maurice et al, 2019). Clonal populations have also been reported within Colletotrichum, such as Colletotrichum kahawae on coffee (Vieira et al, 2018) and the broad host range Colletotrichum fioriniae (Eaton et al, 2021). Other Colletotrichum species show high recombination rates, as observed for C. graminicola on maize (Rogério et al, 2023), Colletotrichum truncatum on soybean (Rogério et al, 2022), and Colletotrichum tanaceti on Australian pyrethrum (Lelwala et al, 2019).…”