全球农业贸易加速了新植物病原体的出现和重新出现。在美国,真菌病原体Colletotrichumliriopes仍然被认为是影响观赏植物的外国检疫病原体,即,Liriopespp.尽管该物种在东亚的各种天冬酰胺寄主上有报道,它在美国的第一份也是唯一一份报告是在2018年。然而,该研究仅使用ITSnrDNA进行鉴定,没有保留可用的培养物或凭证样本。本研究的主要目的是确定被鉴定为C.liripes的标本的地理和寄主分布。要做到这一点,新的和现有的分离株,序列,和从各种宿主和地理位置获得的基因组(即,中国,哥伦比亚,墨西哥,和美国)与前类型的C.liripes进行了比较。多位点系统发育(ITS,Tub2,GAPDH,CHS-1,HIS3),系统发育,和分裂树分析表明,所有研究的分离株/序列都形成了一个支持良好的进化枝,种内变异很小。形态学表征支持这些发现。最小跨越网络,低核苷酸多样性,和阴性田岛的D来自多位点和基因组数据,表明最近有一些东亚基因型向生产观赏植物的其他国家移动/入侵(例如,南美)和,随后,对进口国来说,比如美国。研究表明,严格的C.liriopessensustricto的地理和寄主分布已扩展到美国(即,至少是马里兰州,密西西比州,和田纳西州)以及除天门冬科和兰科以外的各种寄主。本研究产生的基本知识,可用于努力减少农业贸易的成本或损失,扩大我们对病原体运动的理解。
Global agricultural trade has accelerated the emergence and re-emergence of new plant pathogens. In the United States, the fungal pathogen Colletotrichum liriopes is still considered a foreign quarantine pathogen that affects ornamental plants (i.e., Liriope spp.). Even though this species has been reported in East Asia on various asparagaceous hosts, its first and only report in the United States 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 C. liriopes. To accomplish this, new and existing isolates, sequences, and genomes obtained from various hosts and geographic locations (i.e., China, Colombia, Mexico, and the United States) were compared with the ex-type of C. liriopes. Multilocus phylogenetic (ITS, Tub2, GAPDH, CHS-1, and 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 United States. The study reveals that the geographic and host distribution of C. liriopes sensu stricto is expanded to the United States (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.