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Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming 650091, Yunnan Province, PR China
Kevin D. Hyde
Rajesh Jeewon
Lei Cai
Dhanasekaran Vijaykrishna
Centre for Research in Fungal Diversity, Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, PR China
Keqin Zhang 1
Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming 650091, Yunnan Province, PR China
The systematic classification of nematode-trapping fungi is redefined based on phylogenies inferred from sequence analyses of 28S rDNA, 5.8S rDNA and ß-tubulin genes. Molecular data were analyzed with maximum parsimony, maximum likelihood and Bayesian analysis. An emended generic concept of nematode-trapping fungi is provided. Arthrobotrys is characterized by adhesive networks, Dactylellina by adhesive knobs, and Drechslerella by constricting-rings. Phylogenetic placement of taxa characterized by stalked adhesive knobs and non-constricting rings also is confirmed in Dactylellina. Species that produce unstalked adhesive knobs that grow out to form loops are transferred from Gamsylella to Dactylellina, and those that produce unstalked adhesive knobs that grow out to form networks are transferred from Gamsylella to Arthrobotrys. Gamsylella as currently circumscribed cannot be treated as a valid genus. A hypothesis for the evolution of trapping-devices is presented based on multiple gene data and morphological studies. Predatory and nonpredatory fungi appear to have been derived from nonpredatory members of Orbilia. The adhesive knob is considered to be the ancestral type of trapping device from which constricting rings and networks were derived via two pathways. In the first pathway adhesive knobs retained their adhesive material forming simple two-dimension networks, eventually forming complex three-dimension networks. In the second pathway adhesive knobs lost their adhesive materials, with their ends meeting to form nonconstricting rings and they in turn formed constricting rings with three inflated-cells.
Key words: ß-tubulin, evolution, fungi, phylogeny, predatory, systematics, rDNA
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Y. Yang, E. Yang, Z. An, and X. Liu Evolution of nematode-trapping cells of predatory fungi of the Orbiliaceae based on evidence from rRNA-encoding DNA and multiprotein sequences PNAS, May 15, 2007; 104(20): 8379 - 8384. [Abstract] [Full Text] [PDF] |
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