TY - JOUR
T1 - An inordinate fondness for Fusarium
T2 - Phylogenetic diversity of fusaria cultivated by ambrosia beetles in the genus Euwallacea on avocado and other plant hosts
AU - Kasson, Matthew T.
AU - O'Donnell, Kerry
AU - Rooney, Alejandro P.
AU - Sink, Stacy
AU - Ploetz, Randy C.
AU - Ploetz, Jill N.
AU - Konkol, Joshua L.
AU - Carrillo, Daniel
AU - Freeman, Stanley
AU - Mendel, Zvi
AU - Smith, Jason A.
AU - Black, Adam W.
AU - Hulcr, Jiri
AU - Bateman, Craig
AU - Stefkova, Kristyna
AU - Campbell, Paul R.
AU - Geering, Andrew D.W.
AU - Dann, Elizabeth K.
AU - Eskalen, Akif
AU - Mohotti, Keerthi
AU - Short, Dylan P.G.
AU - Aoki, Takayuki
AU - Fenstermacher, Kristi A.
AU - Davis, Donald D.
AU - Geiser, David M.
N1 - Funding Information:
The authors thank the Hofshi Foundation for organizing the Invasive Ambrosia Beetle Conference in August 2012, which greatly facilitated this collaboration. M.T.K. and D.D.D. thank the USDA Forest Service Forest Health Technology Enterprise Team (FHTET), Morgantown, WV, for funding, and Suzanne Slack and Jean Juba for their assistance in the lab. K.S. was funded from the Czech Ministry of Education, Youth and Sports Project no. LH 12098 KONTAKT II CR – USA. C.B. and J.H. were funded from a Cooperative Agreement with the USDA Forest Service, Forest Health Section, and by the Norwegian Research Council. D.P.G.S. was supported by AFRI grant no. 2010-65110-20488 from the USDA NIFA. We are pleased to thank Nathane Orwig for running sequences in the NCAUR DNA Core Facility. A.G., P.C. and E.D. thank Horticulture Australia Limited and Avocados Australia Limited for funding. The mention of firm names or trade products does not imply that they are endorsed or recommended by the US Department of Agriculture over other firms or similar products not mentioned. The USDA is an equal opportunity provider and employer.
PY - 2013/7
Y1 - 2013/7
N2 - Ambrosia beetle fungiculture represents one of the most ecologically and evolutionarily successful symbioses, as evidenced by the 11 independent origins and 3500 species of ambrosia beetles. Here we document the evolution of a clade within Fusarium associated with ambrosia beetles in the genus Euwallacea (Coleoptera: Scolytinae). Ambrosia Fusarium Clade (AFC) symbionts are unusual in that some are plant pathogens that cause significant damage in naïve natural and cultivated ecosystems, and currently threaten avocado production in the United States, Israel and Australia. Most AFC fusaria produce unusual clavate macroconidia that serve as a putative food source for their insect mutualists. AFC symbionts were abundant in the heads of four Euwallacea spp., which suggests that they are transported within and from the natal gallery in mandibular mycangia. In a four-locus phylogenetic analysis, the AFC was resolved in a strongly supported monophyletic group within the previously described Clade 3 of the Fusarium solani species complex (FSSC). Divergence-time estimates place the origin of the AFC in the early Miocene ~21.2. Mya, which coincides with the hypothesized adaptive radiation of the Xyleborini. Two strongly supported clades within the AFC (Clades A and B) were identified that include nine species lineages associated with ambrosia beetles, eight with Euwallacea spp. and one reportedly with Xyleborus ferrugineus, and two lineages with no known beetle association. More derived lineages within the AFC showed fixation of the clavate (club-shaped) macroconidial trait, while basal lineages showed a mix of clavate and more typical fusiform macroconidia. AFC lineages consisted mostly of genetically identical individuals associated with specific insect hosts in defined geographic locations, with at least three interspecific hybridization events inferred based on discordant placement in individual gene genealogies and detection of recombinant loci. Overall, these data are consistent with a strong evolutionary trend toward obligate symbiosis coupled with secondary contact and interspecific hybridization.
AB - Ambrosia beetle fungiculture represents one of the most ecologically and evolutionarily successful symbioses, as evidenced by the 11 independent origins and 3500 species of ambrosia beetles. Here we document the evolution of a clade within Fusarium associated with ambrosia beetles in the genus Euwallacea (Coleoptera: Scolytinae). Ambrosia Fusarium Clade (AFC) symbionts are unusual in that some are plant pathogens that cause significant damage in naïve natural and cultivated ecosystems, and currently threaten avocado production in the United States, Israel and Australia. Most AFC fusaria produce unusual clavate macroconidia that serve as a putative food source for their insect mutualists. AFC symbionts were abundant in the heads of four Euwallacea spp., which suggests that they are transported within and from the natal gallery in mandibular mycangia. In a four-locus phylogenetic analysis, the AFC was resolved in a strongly supported monophyletic group within the previously described Clade 3 of the Fusarium solani species complex (FSSC). Divergence-time estimates place the origin of the AFC in the early Miocene ~21.2. Mya, which coincides with the hypothesized adaptive radiation of the Xyleborini. Two strongly supported clades within the AFC (Clades A and B) were identified that include nine species lineages associated with ambrosia beetles, eight with Euwallacea spp. and one reportedly with Xyleborus ferrugineus, and two lineages with no known beetle association. More derived lineages within the AFC showed fixation of the clavate (club-shaped) macroconidial trait, while basal lineages showed a mix of clavate and more typical fusiform macroconidia. AFC lineages consisted mostly of genetically identical individuals associated with specific insect hosts in defined geographic locations, with at least three interspecific hybridization events inferred based on discordant placement in individual gene genealogies and detection of recombinant loci. Overall, these data are consistent with a strong evolutionary trend toward obligate symbiosis coupled with secondary contact and interspecific hybridization.
UR - http://www.scopus.com/inward/record.url?scp=84879502953&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84879502953&partnerID=8YFLogxK
U2 - 10.1016/j.fgb.2013.04.004
DO - 10.1016/j.fgb.2013.04.004
M3 - Article
C2 - 23608321
AN - SCOPUS:84879502953
SN - 1087-1845
VL - 56
SP - 147
EP - 157
JO - Fungal Genetics and Biology
JF - Fungal Genetics and Biology
ER -