Genome-scale and multi-gene phylogenetic analyses of Colletotrichum spp. host preference and associated with medicinal plants
Qizhou Zhang, Mir Muhammad Nizamani, Yuqing Feng, Yanqi Yang, Ruvishika S. Jayawardena, KD Hyde, Yu Wang, Chao Li
Abstract
Colletotrichum is one of the most common phytopathogens worldwide, causing diseases in various commercially valuable hosts.Several Colletotrichum species have been reported to infect medicinal plants.Although China is a large-scale producer of medicinal plant resources, the species of Colletotrichum that have been locally linked to medicinal plants are poorly understood.Therefore, samples were collected from four provinces of China to determine the Colletotrichum species associated with local medicinal plants, resulting in a total of 141 Colletotrichum isolates.In conjunction with morphology, multi-locus phylogenetic analyses (ITS, gapdh, his3, act, and tub2), and PHI test revealed that these strains belong to 23 species in eight species complexes, including seven new species (C.castaneae, C. cypericola, C. gardeniae, C. kunmingense, C. ligustri, C. radermacherae, and C. schefflerae) and three new host records (C.celtidis, C. iris, and C. vittalense).In addition, we synonymise C. wuxuhaiense to C. karsti, and C. menglaense, C. pandanicola, andC.parvisporum to C. siamense.Furthermore, to understand mechanisms responsible for host range and preference we also sequenced and assembled whole-genome sequences of four species in the C. gloeosporioides complex and constructed whole-genome phylogenies of Colletotrichum species covering ten species complexes and three singleton species.The comparative genome of Colletotrichum species from different lineages revealed that expanded gene families encoding CAZymes are thought to be one of the likely explanations for the widespread and polyphagous nature of species in the C. acutatum, C. boninense, and C. gloeosporioides species complexes.A possible explanation for the host preference of the C. graminicola species complex may be the less pectinase-encoding gene families.The current study improves the understanding of Colletotrichum species diversity found on medicinal plants and suggests that the members of CAZymes might serve as an important mechanism for host range and preference.