title: Three genera in the Ceratocystidaceae are the respective symbionts of three independent lineages of ambrosia beetles with large, complex mycangia.
abstract: The genus Ambrosiella accommodates species of Ceratocystidaceae (Microascales) that are obligate, mutualistic symbionts of ambrosia beetles, but the genus appears to be polyphyletic and more diverse than previously recognized. In addition to Ambrosiella xylebori, Ambrosiella hartigii, Ambrosiella beaveri, and Ambrosiella roeperi, three new species of Ambrosiella are described from the ambrosia beetle tribe Xyleborini: Ambrosiella nakashimae sp. nov. from Xylosandrus amputatus, Ambrosiella batrae sp. nov. from Anisandrus sayi, and Ambrosiella grosmanniae sp. nov. from Xylosandrus germanus. The genus Meredithiella gen. nov. is created for symbionts of the tribe Corthylini, based on Meredithiella norrisii sp. nov. from Corthylus punctatissimus. The genus Phialophoropsis is resurrected to accommodate associates of the Xyloterini, including Phialophoropsis trypodendri from Trypodendron scabricollis and Phialophoropsis ferruginea comb. nov. from Trypodendron lineatum. Each of the ten named species was distinguished by ITS rDNA barcoding and morphology, and the ITS rDNA sequences of four other putative species were obtained with Ceratocystidaceae-specific primers and template DNA extracted from beetles or galleries. These results support the hypothesis that each ambrosia beetle species with large, complex mycangia carries its own fungal symbiont. Conidiophore morphology and phylogenetic analyses using 18S (SSU) rDNA and TEF1α DNA sequences suggest that these three fungal genera within the Ceratocystidaceae independently adapted to symbiosis with the three respective beetle tribes. In turn, the beetle genera with large, complex mycangia appear to have evolved from other genera in their respective tribes that have smaller, less selective mycangia and are associated with Raffaelea spp. (Ophiostomatales).
authors.affiliation: Department of Plant Pathology and Microbiology, Iowa State University, 351 Bessey Hall, Ames, IA 50011, USA.
authors.forename: Chase G
authors.initials: CG
authors.lastname: Mayers
authors.affiliation: Department of Plant Pathology and Microbiology, Iowa State University, 351 Bessey Hall, Ames, IA 50011, USA.
authors.forename: Douglas L
authors.initials: DL
authors.lastname: McNew
authors.affiliation: Department of Plant Pathology and Microbiology, Iowa State University, 351 Bessey Hall, Ames, IA 50011, USA. Electronic address: tcharrin@iastate.edu.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Harrington
authors.affiliation: Department of Biology, Alma College, Alma, MI 48801, USA.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Roeper
authors.affiliation: Southern Research Station, USDA Forest Service, Athens, GA 30602, USA.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Fraedrich
authors.affiliation: Research Group Insect Symbiosis, Max Planck Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll-Str. 8, 07745 Jena, Germany.
authors.forename: Peter H W
authors.initials: PHW
authors.lastname: Biedermann
authors.affiliation: Department of Entomology, Cornell University, R.W. Holley Center for Agriculture and Health, Ithaca, NY 14853, USA.
authors.forename: Louela A
authors.initials: LA
authors.lastname: Castrillo
authors.affiliation: Division of Plant Sciences, University of Missouri, 52 Agriculture Lab, Columbia, MO 65211, USA.
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Reed
mesh_terms: D031164:Ambrosia / Q000469:parasitology; D000818:Animals; D001203:Ascomycota / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology*; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D014644:Genetic Variation; D008969:Molecular Sequence Data; D020648:Peptide Elongation Factor 1 / Q000235:genetics; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013559:Symbiosis; D048889:Weevils / Q000382:microbiology*
chemical_list: D004271:DNA, Fungal; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D020648:Peptide Elongation Factor 1; D012337:RNA, Ribosomal, 18S
keywords: Ambrosia fungi; Scolytinae; Symbiosis