title: Two novel Fusarium species that cause canker disease of prickly ash (Zanthoxylum bungeanum) in northern China form a novel clade with Fusarium torreyae.
abstract: Canker disease of prickly ash (Zanthoxylum bungeanum) has caused a decline in the production of this economically important spice in northern China in the past 25 y. To identify the etiological agent, 38 fungal isolates were recovered from symptomatic tissues from trees in five provinces in China. These isolates were identified by conducting BLASTN queries of NCBI GenBank and phylogenetic analyses of DNA sequence data from the nuclear ribosomal internal transcribed spacer region (ITS rDNA), a portion of the translation elongation factor 1-α (TEF1) gene, and genes encoding RNA polymerase II largest (RPB1) and second largest (RPB2) subunits. Results of these analyses suggested that 30/38 isolates belonged to two novel fusaria most closely related to the Florida torreya (Torreya taxifolia Arn.) pathogen, Fusarium torreyae in Florida and Georgia. These three canker-inducing tree pathogens form a novel clade within Fusarium here designated the F. torreyae species complex (FTOSC). BLASTN queries of GenBank also revealed that 5/38 isolates recovered from cankers represented an undescribed phylogenetic species within the F. solani species complex (FSSC) designated FSSC 6. Stem inoculations of three fusaria on Z. bungeanum resulted in consistent canker symptoms from which these three fusaria were recovered. The two novel fusaria, however, induced significantly larger lesions than FSSC 6. Herein, the two novel prickly ash pathogens are formally described as F. zanthoxyli and F. continuum.
authors.affiliation: College of Forestry, Northwest A&F University, Taicheng Road, Yangling, Shaanxi, China 712100.
authors.forename: Xue
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Mycotoxin Prevention and Applied Microbiology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, US Department of Agriculture, Peoria, Illinois 60604-3999.
authors.forename: Kerry
authors.initials: K
authors.lastname: O'Donnell
authors.affiliation: Genetic Resources Center (MAFF), National Agriculture and Food Research Organization, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Aoki
authors.affiliation: School of Forest Resources and Conservation, University of Florida, Gainesville, Florida 32611-0680.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Smith
authors.affiliation: Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia 26506-6108.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Kasson
authors.affiliation: College of Forestry, Northwest A&F University, Taicheng Road, Yangling, Shaanxi, China 712100 zmcao@nwsuaf.edu.cn.
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Cao
mesh_terms: D002681:China; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005670:Fusarium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D020648:Peptide Elongation Factor 1 / Q000235:genetics; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology*; D012319:RNA Polymerase II / Q000235:genetics; D017422:Sequence Analysis, DNA; D032106:Zanthoxylum / Q000382:microbiology*
chemical_list: D004271:DNA, Fungal; D018744:DNA, Plant; D021903:DNA, Ribosomal Spacer; D020648:Peptide Elongation Factor 1; D012319:RNA Polymerase II
keywords: F. zanthoxyli; Fusarium continuum; RPB2; TEF1; genealogical concordance; molecular phylogenetics; morphology