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| Web URL(s): | https://turf.rutgers.edu/research/abstracts/symposium2004.pdf#page=41
Last checked: 02/06/2017
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Notes: Item is within a single large file |
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| Publication Type:
| Report |
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| Content Type: | Abstract or Summary only |
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| Author(s): | Crouch, Jo Anne;
Clarke, Bruce B.;
Hillman, Bradley I. |
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| Author Affiliation: | Department of Plant Biology and Pathology, Rutgers University |
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| Title: | Evolutionary descent of the phytopathogenic fungus Colletotrichum graminicola |
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| Section: | Posters
Other records with the "Posters" Section
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| Meeting Info.: | Cook College, Rutgers, NJ: January 15-16, 2004 |
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| Source: | Proceedings of the Thirteenth Annual Rutgers TurfgrassSymposium. 2004, p. 40. |
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| Publishing Information: | New Brunswick, NJ: Center for Turfgrass Science, Cook College, Rutgers, The State University of New Jersey |
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| # of Pages: | 1 |
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| Keywords: | TIC Keywords: Anthracnose; Colletotrichum graminicola; Evaluations; Genetic analysis; Loci; Phylogeny
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| Abstract/Contents: | "The evolutionary history of Colletotrichum graminicola, the causal agent of anthracnose in turfgrass and cereal crops, was reconstructed in the form on a phylogenetic tree using nucleotide sequences drawn from 80 fungal isolates of diverse geographic and host-plant origin. Three unlinked loci were included in the analysis: (1) the internal transcribed spacer region of the ribosomal DNA, (2) a portion of the superoxide dismutase gene, which included two introns, and (3) the conserved HMG-box found within the MAT-2 idiomorph of the fungal mating loci. In total, 1,428 nucleotides from the three genes were included in the analysis. To infer the evolutionary hypothesis from the aligned sequence data, maximum likelihood optimality criterion was employed because of its ability to efficiently estimate phylogenetic tree branching pathways based on an explicit model of evolution. Analysis of the nucleotide sequences demonstrated that each of the three genes had sufficient signal to consistently establish three main groups among the C. graminicola isolates. In order to test whether it was appropriate to combine the individual gene sequences into a single dataset, the statistical significance of topological congruence between the individual gene trees was evaluated by comparing optimal gene tree topologies to constrained trees using the Shimodaira-Hasegawa likelihood ratio test (LRT). The LRT established that none of the individual data sets significantly rejects the topology of the others. Concordance among the individual gene trees suggests that each reflects the species phylogeny and that is is appropriate to combine the characters into a single dataset. Interpretation of C. graminicola's evolutionary pathway as reconstructed by the combined dataset demonstrates a pattern of relative genetic homeostasis. The fungus is characterized by large, widespread populations which may have served to minimize significant adaptive change in ancestral poplulations of the fungus. As estimated by Bayesian posterior probablities, support for the phylogenetic reconstruction is strong, with the recovery of three main groups. C. graminicola isolates from corn plants form a distinct monophyletic clade well removed from the turfgrass evolutionary path. The considerable level of diversification manifested between the grass and corn lineages suggests the occurrence of a speciation even between these two host-specific populations. Among the separate branch of the turfgrass lineages the tree bifurcates into two smaller groupings: clade A and B. The fungi included within clade A are derived from both Poa annua and Agrostis spp. turfgrass host plants; nevertheless they are quite closely related to one another. In contrast, clade B splits into two smaller sub-clades that appear to be evolving with some degree of host specificity: sub-clade B1 contains only fungi isolated from Agrostis spp.; sub-clade B2 isolates are uniquely derived from Poa annua host plants. Given the patterns of evolutionary descent suggested by the data, we discuss the potential development of habitat preference arising by sympatric population subdivision, with a concurrent reduction of gene flow and physiological isolation evolving as the lineages adapt to different ecological niches." |
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| Language: | English |
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| References: | 0 |
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| Note: | This item is an abstract only! |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Crouch, J. A., B. B. Clarke, and B. I. Hillman. 2004. Evolutionary descent of the phytopathogenic fungus Colletotrichum graminicola. Proc. Annu. Rutgers Turfgrass Symp. p. 40. |
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| Web URL(s):
https://turf.rutgers.edu/research/abstracts/symposium2004.pdf#page=41
Last checked: 02/06/2017
Requires: PDF Reader
Notes: Item is within a single large file |
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MSU catalog number: SB 433 .R88 |
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