Yellow sigatoka epidemics caused by a panmictic population of Mycosphaerella musicola in Brazil

Abstract

The genetic structure of Mycosphaerella musicola has never been investigated in Brazil to address epidemiologically related questions associated with yellow sigatoka. A total of 223 single‐conidium isolates from four regions (North, South, Zona da Mata and Triângulo Mineiro) of Minas Gerais State, Brazil, were used to assess the population genetic structure of M. musicola. Isolates were characterized regarding the frequency of the MAT1‐1‐1 or MAT1‐2‐1 idiomorphs and polymorphism at nine microsatellite loci. The mating‐type ratio in three of the four subpopulations was c. 1:1. A total of 87 alleles and 216 multilocus genotypes were identified. The overall population was in linkage equilibrium. Most (93.9%) genetic variation was detected within the subpopulations and there was weak differentiation between them. In total, eight genetic groups were detected and isolates of seven groups were present in all regions. The population of M. musicola in Minas Gerais seems to have high evolutionary potential: it is panmictic and both sexual reproduction and gene flow affect genetic variability. Strategies to avoid fungicide resistance should be enforced and breeding programmes need to consider quantitative resistance in the banana cultivars.

Genetic variability of Pseudocercospora fijiensis, the black Sigatoka pathogen of banana (Musa spp.) in Mexico

“…The pattern presented here is consistent with the current knowledge for P. fijiensis and P. musicola (Carlier et al, 2002;Gomes et al, 2018), and is also consistent with the proposal that, although the transport of infected material or wind can be effective forms of dispersal, once the strains colonize a new locality, the movement of spores or other propagules between populations is rare. The genetic drift seems to be the most important evolutionary driver for P. fijiensis at local (population) and global (metapopulations) levels.…”

“…Chiapas and Tabasco), than a putative younger population (Colima). Similar conclusions were reported by Gomes et al (2018) for Pseudocercospora musicola in Brazil; older populations tend to be more diverse.…”

“…Similar conclusions were reported by Gomes et al . () for Pseudocercospora musicola in Brazil; older populations tend to be more diverse.…”

“…Finally, the data agree with authors who propose that P. fijiensis , like other related fungal species, is a pathogen with a high evolutionary capacity (Chang et al ., ; but compare with Zhan & McDonald, ; Poppe et al ., ). However, this evolutionary capacity means there is a major challenge not only to obtain a complete understanding of the evolutionary dynamics of the fungus, but also to develop resistant host varieties and prevent resistance breakdown; also, genetic variation in the pathogen population can affect the efficiency of fungicides, especially those that are based on site‐specific targets (Gomes et al ., , and references therein). One further line of investigation is to perform phylogeographic studies of populations in order to define with more precision the evolutionary tendencies of the pathogen in Mexico.…”

Genetic Diversity and Azole Fungicide Sensitivity in Pseudocercospora musae Field Populations in Brazil

“…For P. fijiensis (Zhan et al, 2002;Conde-Ferráez et al, 2010;Queiroz et al, 2013) and Zymoseptoria tritici (Gurung et al, 2011), analysis of the mating type region has often revealed a frequency close to 1:1 of MAT1-1 and MAT1-2, indicating regular cycles of sexual recombination during the crop growing season. Unlike these Dothideomycete fungal species, analysis of the distribution of mating type idiomorphs in P. musae populations has so far been limited (Gomes et al, 2017).…”