Phylogeographic and phylogenomic structure of the quarantine plant pathogen Colletotrichum liriopes , including new reports in the United States.

Global agricultural trade has accelerated the emergence and re-emergence of new plant pathogens. In the United States, the fungal pathogen is still considered a foreign quarantine pathogen that affects ornamental plants, i.e., spp. Even though this species has been reported in East Asia on various asparagaceous hosts, its first and only report in the USA was in 2018. However, that study used only ITS nrDNA for identification and no available culture or voucher specimen was maintained. The main objective of the present study was to determine the geographic and host distribution of specimens identified as To accomplish this, new and existing isolates, sequences, and genomes obtained from various hosts and geographic locations (i.e., China, Colombia, Mexico, and United States) were compared to the ex-type of . Multilocus phylogenetic (ITS, Tub2, GAPDH, CHS-1, HIS3), phylogenomic, and splits tree analyses revealed that all the studied isolates/sequences form a well-supported clade with little intraspecific variation. Morphological characterizations support these findings. The Minimum Spanning Network, low nucleotide diversity, and negative Tajima's D from both multilocus and genomic data, suggest that there was a recent movement/invasion of a few East Asian genotypes to other countries where the ornamental plants are produced (e.g., South America) and, subsequently, to the importing countries, such as the USA. The study reveals that the geographic and host distribution of is expanded to the USA (i.e., at least Maryland, Mississippi, and Tennessee) and on various hosts in addition to Asparagaceae and Orchidaceae. The present study produces fundamental knowledge that can be used in efforts to reduce costs or losses from agricultural trade, and to expand our understanding of pathogen movement.