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Population Biology

Global Analysis of Hemileia vastatrix Populations Shows Clonal Reproduction for the Coffee Leaf Rust Pathogen Throughout Most of Its Range

    Authors and Affiliations
    • Luis A. Ramírez-Camejo1 2 3
    • Amnat Eamvijarn1 4
    • Jorge R. Díaz-Valderrama1
    • Elena Karlsen-Ayala1 5
    • Rachel A. Koch1
    • Elizabeth Johnson6
    • Sòlene Pruvot-Woehl7
    • Luis C. Mejía2
    • Christophe Montagnon8
    • Casto Maldonado-Fuentes9
    • M. Catherine Aime1
    1. 1Purdue University, Department of Botany and Plant Pathology, West Lafayette, IN 47901, U.S.A.
    2. 2Center for Biodiversity and Drug Discovery, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Ciudad del Saber, Ancón, Republic of Panama
    3. 3Coiba Scientific Station (COIBA AIP), City of Knowledge, Clayton, Panama, Republic of Panama
    4. 4Department of Agriculture, Chatuchak, Bangkok, Thailand
    5. 5University of Florida, Department of Plant Pathology, Gainesville, FL, U.S.A.
    6. 6Inter-American Institute for Cooperation on Agriculture, Hope Gardens, Kingston, Jamaica
    7. 7World Coffee Research, 34270 Saint Mathieu de Tréviers, France
    8. 8RD2 Vision, 34270 Valflaunes, France
    9. 9Facultad de Agronomía, Universidad Mayor de San Andrés, Sapecho, La Paz, Bolivia

    Hemileia vastatrix is the most important fungal pathogen of coffee and the causal agent of recurrent disease epidemics that have invaded nearly every coffee growing region in the world. The development of coffee varieties resistant to H. vastatrix requires fundamental understanding of the biology of the fungus. However, the complete life cycle of H. vastatrix remains unknown, and conflicting studies and interpretations exist as to whether the fungus is undergoing sexual reproduction. Here we used population genetics of H. vastatrix to infer the reproductive mode of the fungus across most of its geographic range, including Central Africa, Southeast Asia, the Caribbean, and South and Central America. The population structure of H. vastatrix was determined via eight simple sequence repeat markers developed for this study. The analyses of the standardized index of association, Hardy–Weinberg equilibrium, and clonal richness all strongly support asexual reproduction of H. vastatrix in all sampled areas. Similarly, a minimum spanning network tree reinforces the interpretation of clonal reproduction in the sampled H. vastatrix populations. These findings may have profound implications for resistance breeding and management programs against H. vastatrix.