<b><i>C</i></b><b>olletotrichum species_Alignments</b>

<i>Colletotrichum</i> is a cosmopolitan fungal genus known for its important role as a plant pathogen. Its species cause diseases such as anthracnose, leaf spots, blights, and rots, impacting a wide range of hosts. <i>Colletotrichum</i> species also exhibit endophytic and saprobic life modes. The genus comprises species complexes, many of which include cryptic species that are morphologically similar but phylogenetically distinct. The genus is characterized by hyaline and aseptate ascospores and conidia, with the ascospores being cylindrical to oval or fusiform, and the conidia mostly ellipsoidal to ovoid. As part of ongoing research on phytopathogenic fungi, we gathered diseased leaves and pods with spots, blight and blotches from Chiang Mai, Chiang Rai, and Tak provinces in Thailand. For species identification and delimitation, we employed a biphasic approach incorporating morphological data and multigene phylogenetic analyses of the locus of the internal Transcribed Spacer (ITS, nuclear rDNA consisting of ITS1-5.8S-ITS2), and the genes encoding for glyceraldehyde-3-phosphate dehydrogenase (<i>GAPDH</i>), chitin Synthase 1 (<i>CHS</i>1), actin (<i>ACT</i>), beta-tubulin 2 (<i>TUB</i>2), histone (<i>H</i>3), and calmodulin (<i>CAM</i>). We obtained 20 <i>Colletotrichum</i> isolates representing eight species, among which we propose two new species: <i>Colletotrichum dendrobii</i> (from <i>Dendrobium</i> sp.) and <i>C. musichiangmaiense</i> (from <i>Musa</i> sp.). We also establish 13 new host records (for six species): <i>C. castaneae</i> (on <i>Jasminum grandiflorum</i>), <i>C. chrysophilum</i> (on <i>Terminalia</i> sp.), <i>C. endophyticum</i> (on <i>Artocarpus heterophyllus</i>, <i>Begonia luxurians</i>, <i>Cassia</i> sp., <i>Castanopsis</i> sp., <i>Ficus auriculata</i>, and <i>Schefflera</i> sp.), <i>C. fructicola</i> (on <i>Castanea</i> sp., <i>Hedychium</i> sp., and <i>Rhododendron</i> sp.), <i>C. jiangxiense</i> (on <i>Artocarpus</i> sp.), and <i>C. schimae</i> (on <i>Jasminum</i> sp.). In addition, this is the first study to present the sexual morph of <i>C. endophyticum</i> and to synonymize <i>C. noveboracense</i> under <i>C. chrysophilum</i>.