study of the genetic variability of Rhizoplaca chrysoleuca using DNA sequences and secondary metabolic substances

• Published in: Mycologia Vol. 98; no. 1; pp. 57 - 67
• Main Authors: Zhou, Qi-Ming, Guo, Shou-Yu, Huang, Man-Rong, Wei, Jiang-Chun
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 2006; Mycological Society of America
• Subjects: Ascomycota - chemistry; Ascomycota - classification; Ascomycota - genetics; Benzofurans - analysis; chemotype; chemotypes; Chromatography, Thin Layer; DNA, Fungal - chemistry; DNA, Fungal - genetics; DNA, Fungal - isolation & purification; DNA, Ribosomal - chemistry; DNA, Ribosomal - genetics; DNA, Ribosomal - isolation & purification; DNA, Ribosomal Spacer - chemistry; DNA, Ribosomal Spacer - genetics; DNA, Ribosomal Spacer - isolation & purification; Evolutionary genetics; fungal anatomy; Fungi; Genes, rRNA - genetics; Genetic Variation; group I intron; Hydroxybenzoates - analysis; insertion distribution pattern; internal transcribed spacers; Introns; Introns - genetics; ITS; Lecanorales; Lichens; Molecular Evolution and Systematics; Molecular Sequence Data; molecular systematics; Phylogenetics; Phylogeny; Polymerase chain reaction; Rhizoplaca chrysoleuca; Ribosomal DNA; RNA, Fungal - genetics; RNA, Ribosomal - genetics; Salicylates - analysis; secondary metabolites; Sequence Analysis, DNA; Speciation; Specimens; SSU rDNA; Thallus; China
• ISSN: 0027-5514; 1557-2536
• DOI: 10.1080/15572536.2006.11832713

Specimens of Rhizoplaca chrysoleuca from Mount Wuling can be divided into two distinct groups based on obvious differences in morphological characters. Here we investigated 26 specimens of R. chrysoleuca from Mount Wuling, 10 specimens of this species from other areas and seven specimens of other Rhizoplaca species by analyzing morphology, chemistry and genetics. Nine chemotypes were detected among the specimens of R. chrysoleuca from Mount Wuling, and five of them were reported for the first time. Based on the ITS phylogenetic analysis, the chemotypes and the insertion distribution patterns in SSU rDNA, the samples of R. chrysoleuca from Mount Wuling were grouped in two distinct clades corresponding to two phenotypic groups and no gene flow was detected between these two groups. Our results establish all individuals of Rhizoplaca chrysoleuca are conspecific although some populations have been isolated on Mount Wuling, indicating that they are in the process of speciation. Our study also reveals that the relationships between genotypes and chemotypes are complicated and should be avoided, and we instead recommend using single individuals or few individuals from the same site to represent the population or whole species in systematics study. The results also indicate that Rhizoplaca chrysoleuca might provide a good model for studying the speciation of saxicolous lichenized fungi.