Cataloging Species of Agriculture, Forests, Horticulture, and Restoration Outplantings in California, U.S.A.: A Sequence-Based Meta-Analysis.

California contains a diverse flora, and knowledge of the pathogens that threaten those plants is essential to managing their long-term health. To better understand threats to California plant health, a meta-analysis of detections within the state was conducted using publicly available sequences as a primary source of data rather than published records. Accessions of internal transcribed spacer (ITS) ribosomal DNA were cataloged from 800 Californian isolates, analyzed, and determined to correspond to 80 taxa, including several phylogenetically distinct provisional species. A number of taxa not previously reported from California were identified, including 20 described species. Pathways of introduction and spread were analyzed by categorizing isolates' origins, grouped by land-use: (i) agriculture, (ii) forests and other natural ecosystems, (iii) horticulture and nurseries, or (iv) restoration outplantings. The pooled metacommunities of the restoration outplantings and horticulture land-use categories were the most similar, whereas the communities pooled from forests and agriculture were least similar. , and were identified in all four land-use categories, while 13 species were found in three. was the most common species by number of ITS accessions and exhibited the greatest diversity of ITS haplotypes. , and were associated with the greatest number of host genera. In this analysis, the spp. most prevalent in California differ from those compiled from the scientific literature.