Cryptosexuality and the genetic diversity paradox in coffee rust, Hemileia vastatrix

Despite the fact that coffee rust was first investigated scientifically more than a century ago, and that the disease is one of the major constraints to coffee production - constantly changing the socio-economic and historical landscape of the crop - critical aspects of the life cycle of the pathoge...

Descripción completa

Detalles Bibliográficos
Autores: Carvalho, Carlos Roberto, Fernandes, Ronaldo C., Carvalho, Guilherme Mendes Almeida, Barreto, Robert W., Evans, Harry C.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2011
País:Brasil
Institución:Universidade Federal de Viçosa (UFV)
Repositorio:LOCUS Repositório Institucional da UFV
Idioma:inglés
OAI Identifier:oai:locus.ufv.br:123456789/12890
Acceso en línea:https://doi.org/10.1371/journal.pone.0026387
http://www.locus.ufv.br/handle/123456789/12890
Access Level:acceso abierto
Palabra clave:Cryptosexuality
Genetic Diversity
Hemileia vastatrix
Descripción
Sumario:Despite the fact that coffee rust was first investigated scientifically more than a century ago, and that the disease is one of the major constraints to coffee production - constantly changing the socio-economic and historical landscape of the crop - critical aspects of the life cycle of the pathogen, Hemileia vastatrix, remain unclear. The asexual urediniospores are regarded as the only functional propagule: theoretically, making H. vastatrix a clonal species. However, the well-documented emergence of new rust pathotypes and the breakdown in genetic resistance of coffee cultivars, present a paradox. Here, using computer-assisted DNA image cytometry, following a modified nuclear stoichiometric staining technique with Feulgen, we show that meiosis occurs within the urediniospores. Stages of spore development were categorised based on morphology, from the spore-mother cell through to the germinating spore, and the relative nuclear DNA content was quantified statistically at each stage. Hidden sexual reproduction disguised within the asexual spore (cryptosexuality) could explain why new physiological races have arisen so often and so quickly in Hemileia vastatrix. This could have considerable implications for coffee breeding strategies and may be a common event in rust fungi, especially in related genera occupying the same basal phylogenetic lineages.