Speciation of a tropical fungal species pair following transoceanic dispersal

Proteomic analysis of proteins differentially expressed in conidia and mycelium of the entomopathogenic fungus Aschersonia placenta

The infection of insects by the entomopathogenic fungus Aschersonia placenta depends on conidia. To identify proteins differentially expressed in A. placenta conidia vs mycelia, we performed a comparative proteomic analysis of A. placenta using 2-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS). We detected 1022 2-DE protein spots in conidia and 1049 in mycelia and analyzed 48 (13 from conidia and 35 from mycelia) using MALDI-TOF-MS. Finally, we identified 28 proteins (7 from conidia and 21 from mycelia). The identified proteins exclusive to conidia included major proteins participating in oxidation–reduction processes and vegetative insecticidal protein 1 (Vip1), a protein that is likely involved in pathogenicity. The identified proteins exclusive to mycelia were those involved in biosynthesis and metabolism, including uridine diphosphate galactopyranose mutase, which might play key roles in hyphal morphogenesis. This report provides the first proteomic analysis of different developmental stages of an Aschersonia species. Although only a small number of proteins were identified, the data represent a useful foundation for future studies concerning the molecular basis of entomopathogenicity in the species A. placenta and in the genus Aschersonia.

Multigene molecular phylogenetics reveals true morels (Morchella) are especially species-rich in China

The phylogenetic diversity of true morels (Morchella) in China was estimated by initially analyzing nuclear ribosomal internal transcribed spacer (ITS) rDNA sequences from 361 specimens collected in 21 provinces during the 2003-2011 growing seasons, together with six collections obtained on loan from three Chinese herbaria. Based on the results of this preliminary screen, 40 Esculenta Clade (yellow morels) and 30 Elata Clade (black morels) were chosen to represent the full range of phylogenetic diversity sampled. To investigate their species limits, we generated DNA sequences from portions of three protein-coding genes (RPB1, RPB2 and EF-1α) and domains D1 and D2 of the nuclear large subunit (LSU) rDNA for all 70 collections. To fully assess evolutionary relationships, previously published multilocus DNA sequence data representing all known Morchella species was included in this study. Phylogenetic analyses employing maximum parsimony and maximum likelihood frameworks resolved 30 species in China compared with 22 in Europe and 19 within North America. Eleven novel phylogenetically distinct species were discovered in China, including two species within the Elata Clade and nine within the Esculenta Clade. Of the 30 species in China, 20 appear to be endemic, nine were also represented in Europe, and four putatively fire-adapted species have disjunct distributions in China, Europe and western North America. Although the diversification time estimates place the Esculenta Clade in China as early as the late Cretaceous and the Elata Clade by the early Oligocene, 27 of the 30 species evolved between the middle Miocene 12Mya and present.

Multigene phylogenetic and population differentiation data confirm the existence of a cryptic species within Chrysoporthe cubensis

Chrysoporthe cubensis is one of the most important pathogens of Eucalyptus. Based on phylogenetic evidence and geographic origin, isolates of this fungus are known to reside in distinct 'South America' and 'Southeast Asia' clades. In this study, reproductive isolation amongst these isolates of C. cubensis was tested using gene flow statistics for 12 polymorphic loci, and to support these data, phylogenetic affiliations based on gene trees and a multigene phylogeny were used. Gene flow statistics between populations, and relative to the closely related Chrysoporthe austroafricana, were low and not significantly different (P<0.05). Additionally, phylogenetic analyses of DNA sequence data for four gene regions convincingly distinguished the two subclades of C. cubensis. Isolates in the Southeast Asian subclade are described in the new species, Chrysoporthe deuterocubensis. Chrysoporthe cubensis and C. deuterocubensis represent closely related fungi that are thought to be native to South America and Southeast Asia, respectively. A technique is presented that allows for rapid differentiation between these species and that will aid in quarantine procedures to limit their spread to new environments.

Phylogeography and divergence date estimates of a lichen species complex with a disjunct distribution pattern

Disjunct species distributions may result from a combination of geologic events and long-distance dispersal. The foliose lichen species complex Leptogium furfuraceum-L. pseudofurfuraceum has an intercontinental disjunction pattern. Populations of this species complex are found in western North America, southern South America, Africa, and southern Europe. We conducted a phylogenetic study to reconstruct the biogeographic history of this species complex using two ribosomal genes (ITS and LSU) and a protein-coding gene (partial RPB2). Results indicated that the complex comprises four geographically restricted genetic lineages. A sister relationship was found between populations from the same hemispheres, incongruent with previous data derived from morphological characteristics and geographical classification schemes. Incorporating Bayesian ancestral area reconstruction and Bayesian divergence time estimation, we proposed an evolutionary hypothesis for the species complex. The results suggested that processes of biotic expansion via transoceanic dispersal were responsible for the species divergence and distribution patterns observed today. This study also expands the view that cryptic speciation is not a rare phenomenon among fungi and lichens.