Variation in from plantations in YunNan Province in southwestern China across a climatic gradient.

The accommodates many important pathogens of woody plants, including . Recently, were isolated from diseased plant parts from surveys of plantations in the YunNan Province, China. The aims of this study were to identify these isolates and to evaluate their pathogenicity to . A total of 166 isolates of were obtained from six regions in the YunNan Province, of which 76 were from × hybrids, 49 from trees, and 41 isolates were from other unknown species or hybrids. Isolates were identified by comparing DNA sequences of the internal transcribed spacer ribosomal RNA locus (ITS), partial translation elongation factor 1-alpha (), β-tubulin 2 () and DNA-directed RNA polymerase II subunit () genes, and combined with their morphological characteristics. Eleven species were identified, including , , , , , and six novel species described as , , , , and . The dominant species across the regions were , and , representing 31.3, 25.3 and 19.9% of the total isolates, respectively. Species diversity and composition changed across the different climatic zones, despite their relatively close geographic proximity and the fact that some of the species have a global distribution. All the species were pathogenic to one-year-old plants of an × clone and seed-derived plants, but showed significant inter- and intra-species variation in aggressiveness amongst isolates. The study provides a foundation for monitoring and management of through selection and breeding of in the YunNan Province of southwestern China.