Diversity and Pathogenicity of Colletotrichum Species Causing Coffee Anthracnose in China

Coffee is a significant traded commodity for developing countries. Among the various diseases affecting coffee, anthracnose caused by <i>Colletotrichum</i> spp. has re-emerged as a major constraint on global coffee production. To better understand the <i>Colletotrichum</i> species complex associated with coffee anthracnose, we characterized <i>Colletotrichum</i> spp. using a combination of phenotypic traits, <i>MAT1-2</i> (ApMat) gene analysis, multi-locus phylogenetic (<i>ITS</i>, <i>ACT</i>, <i>CHS-1</i>, and <i>GAPDH</i>), and pathogenicity assays. A total of 74 <i>Colletotrichum</i> isolates were collected from coffee plants exhibiting anthracnose symptoms across nine coffee plantations in China. Among these, 55 isolates were identified as the <i>C. gloeosporioides</i> species complex using the <i>ApMat</i> locus, while the remaining 19 isolates were identified through multi-locus phylogenetic analyses. The isolates represented seven <i>Colletotrichum</i> species from five species complexes: <i>C. gloeosporioides</i> (including <i>C. siamense</i>, <i>C. nupharicola</i>, and <i>C. theobromicola</i>), <i>C. boninens</i> (<i>C. karstii</i>), <i>C. gigasporum</i> (<i>C. gigasporum</i>), <i>C. orchidearum</i> (<i>C. cliviicola</i>), and <i>C. magnum</i> (<i>C. brevisporum</i>). This is the first report of <i>C. nupharicola</i> and <i>C. cliviicola</i> causing coffee anthracnose worldwide, and the first report of <i>C. nupharicola</i> in China. Pathogenicity tests confirmed that all seven species were capable of infecting coffee leaves. This research enhances our understanding of the <i>Colletotrichum</i> species responsible for coffee anthracnose, and provides valuable insights for developing effective disease management strategies.