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United States Department of Agriculture

Agricultural Research Service


Location: Bacterial Foodborne Pathogens & Mycology Research Unit

Title: An inordinate fondness for Fusarium: Phylogenetic diversity of fusaria cultivated by Euwallacea ambrosia beetles on avocado and other plant hosts

item Kasson, Matthew -
item O Donnell, Kerry
item Rooney, Alejandro
item Sink, Stacy
item Ploetz, Randy -
item Ploetz, Jill -
item Konkol, Joshua -
item Carrillo, Daniel -
item Freeman, Stanley -
item Mendel, Zvi -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 14, 2013
Publication Date: N/A

Technical Abstract: Ambrosia beetle fungiculture represents one of the most ecologically and evolutionarily successful symbioses. 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. 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. 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. Overall, these data are consistent with a strong evolutionary trend toward obligate symbiosis coupled with secondary contact and interspecific hybridization.

Last Modified: 4/20/2014
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