Multilocus identification and thiophanate‐methyl sensitivity of Colletotrichum gloeosporioides species complex associated with fruit with symptoms and symptomless leaves of mango

Abstract

Colletotrichum spp. are known causal agents of anthracnose in a broad host range, causing severe losses. Currently, the most effective way to reduce disease is by fungicide application, which could give rise to resistant populations. This study aimed to determine the Colletotrichum species present in conventional and organic mango orchards and to evaluate their pathogenicity and sensitivity to the benzimidazole fungicide thiophanate‐methyl. Seventy‐one isolates from fruit with symptoms and symptomless leaves were obtained. From these, 20 representative morphotypes were analysed based on glyceraldehyde‐3‐phosphate dehydrogenase partial gene sequencing. A subset of 10 isolates based on different species, isolation source, and fungicide sensitivity was used for morphological and multilocus phylogenetic analysis. Colletotrichum queenslandicum was only identified in conventional production systems, C. chrysophilum only in organic systems, and C. asianum and C. siamense in both. Pathogenicity tests showed all species were pathogenic, and only C. asianum caused symptoms via both unwounded and wounded inoculation methods. Overall, 25.3% of isolates (n = 18) that belong to C. siamense, isolated from a conventional orchard, grew on thiophanate‐methyl amended media at 1,000 µg/ml, suggesting high resistance. Resistance was not correlated with any common point mutations at positions 198 and 200 of the β‐tubulin 2 protein, as commonly found in other fungal pathogens resistant to benzimidazole. The 74.7% remaining isolates (n = 53) belonging to the other species were sensitive, reaching 100% inhibition at <10 µg/ml. Even with benzimidazole application, anthracnose symptoms persist due to the emergence of pathogenic Colletotrichum subpopulations that are resistant to thiophanate‐methyl.

Copper-Modified Double-Emission Carbon Dots for Rapid Detection of Thiophanate Methyl in Food

“…In order to control fungus and ensure the high quality and high yield output of agricultural products, pesticides are widely used in agricultural production activity [ 31 ]. In fruit and vegetable fields, TM is often used to prevent and control various diseases in crops, as well as for postharvest food storage and preseed planting treatment [ 32 , 33 ]. Studies have shown that long-term exposure to TM can pose high risks to human health due to its potential genotoxicity, neurotoxicity, reproductive toxicity and teratogenicity [ 34 , 35 , 36 ].…”

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

“…C . chrysophilum was recently isolated and described in Brazil from anthracnose in bananas (Vieira et al ., 2017) and was found to be associated with anthracnose on mango in Mexico (Fuentes‐Aragón et al ., 2020).…”

“…Knowledge of the diversity of Colletotrichum species associated with a host is crucial for the implementation of efficient management strategies because some species are better adapted than others in the field. Habituation of some Colletotrichum species is enhanced by factors such as high or inherent resistance to fungicides (Chen et al ., 2018; Fuentes‐Aragón et al ., 2020), the development of sexual morphs that are epidemiologically important for genetic recombination, or virulence grades (Sharma et al ., 2017; De Silva et al ., 2019; Fuentes‐Aragón et al ., 2020). In addition, monitoring quarantined pathogens requires precise identification to avoid spreading (Weir et al ., 2012; Crous et al ., 2016).…”

Design, synthesis and Anti‐PVY activity of planar chiral thiourea derivatives incorporated with [2.2]Paracyclophane

“…11 For example, thiophanate and thiophanate-methyl containing two thiourea units are broad-spectrum systemic fungicides that could effectively protect plants from the pathogen fungi. 12,13 The thiourea-based insecticides, such as diafenthiuron, chloromethiuron and buprofezin, are used for the control of insect pests on crops. [14][15][16] The rodenticide antu possesses a simple chemical structure, consisting of naphthalene combined with a thiourea scaffold.…”