Articles
Genetic and pathogenic diversity of Colletotrichum species associated with apple diseases in southern Brazil and Uruguay
Article number
1261_13
Pages
71 – 76
Language
English
Abstract
Two distinct diseases can be caused by Colletotrichum spp. on apple (Malus domestica); apple bitter rot (ABR) and Glomerella leaf spot (GLS). ABR is an old fruit disease occurring in most countries where apple is commercially cultivated.
In contrast, GLS was first observed in the USA in 1970, and since then, it has been reported as an emerging leaf disease in different countries, such as Brazil in 1988 and China in 2012. In Brazil, GLS-outbreaks have become more frequent in the last years, making this disease one of the most important constraints for further cultivation of susceptible apples descending from Golden Delicious, like Gala. Symptoms of GLS begin with small reddish-purple leaf spots about two days after pathogen infection, evolving into larger irregular necrotic lesions a few days later.
Leaves usually turn yellow and fall off resulting in severe tree defoliation.
Interestingly, whereas most isolates show organ specialization causing either ABR or GLS, only a few of them can provoke both diseases.
Both ABR and GLS occur in Brazil, but only the former in Uruguay.
Multilocus sequence analysis allowed the identification of three species causing ABR and GLS in Brazil, Colletotrichum fructicola, C. karstii, and C. nymphaeae, and four species causing ABR in Uruguay, C. fructicola, C. theobromicola, C. melonis, and C. paranaense. As C. fructicola is the most frequent species in both countries, genetic structure of isolates was determined using ISSR-based analysis and vegetative compatibility groups (VCGs). Both populations showed similar levels of Neis diversity, and Bayesian cluster analysis inferred two genetic clusters correlated with the geographical origin of isolates.
Moreover, all Uruguayan isolates were grouped into a unique VCG, while Brazilian isolates were grouped into four VCGs. C. fructicola isolates causing ABR and GLS in southern Brazil revealed to be genetically distinct and arose independently from the Uruguayan population.
In contrast, GLS was first observed in the USA in 1970, and since then, it has been reported as an emerging leaf disease in different countries, such as Brazil in 1988 and China in 2012. In Brazil, GLS-outbreaks have become more frequent in the last years, making this disease one of the most important constraints for further cultivation of susceptible apples descending from Golden Delicious, like Gala. Symptoms of GLS begin with small reddish-purple leaf spots about two days after pathogen infection, evolving into larger irregular necrotic lesions a few days later.
Leaves usually turn yellow and fall off resulting in severe tree defoliation.
Interestingly, whereas most isolates show organ specialization causing either ABR or GLS, only a few of them can provoke both diseases.
Both ABR and GLS occur in Brazil, but only the former in Uruguay.
Multilocus sequence analysis allowed the identification of three species causing ABR and GLS in Brazil, Colletotrichum fructicola, C. karstii, and C. nymphaeae, and four species causing ABR in Uruguay, C. fructicola, C. theobromicola, C. melonis, and C. paranaense. As C. fructicola is the most frequent species in both countries, genetic structure of isolates was determined using ISSR-based analysis and vegetative compatibility groups (VCGs). Both populations showed similar levels of Neis diversity, and Bayesian cluster analysis inferred two genetic clusters correlated with the geographical origin of isolates.
Moreover, all Uruguayan isolates were grouped into a unique VCG, while Brazilian isolates were grouped into four VCGs. C. fructicola isolates causing ABR and GLS in southern Brazil revealed to be genetically distinct and arose independently from the Uruguayan population.
Publication
Authors
M.J. Stadnik, A.C. Velho, M.F. Rockenbach, S. Alaniz, P. Mondino
Keywords
apple bitter rot, Colletotrichum fructicola, Glomerella leaf spot, pathogenicity
Groups involved
Online Articles (39)