Open AccessMorphology, genetic diversity, temperature tolerance and toxicity of Cylindrospermopsis raciborskii (Nostocales, Cyanobacteria) strains from Thailand and Japan
Author(s) -
Chonudomkul Duenrut,
Yongmanitchai Wichien,
Theeragool Gunjana,
Kawachi Masanobu,
Kasai Fumie,
Kaya Kunimitsu,
Watanabe Makoto M.
Publication year - 2004
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1016/j.femsec.2004.02.014
Subject(s) - cylindrospermopsis raciborskii , biology , phylogenetic tree , 16s ribosomal rna , strain (injury) , ecotype , botany , cyanobacteria , genetic diversity , bacteria , genetics , population , gene , anatomy , demography , sociology
Cylindrospermopsis raciborskii is a planktonic, nostocalean cyanobacterium, which produces an alkaloid heptatoxin, cylindrospermopsin. We performed morphological observations, 16S rDNA sequence analysis, PCR fingerprint analysis of short tandemly repeated repetitive (STRR) sequences, temperature tolerances and toxin analysis to characterize 24 strains of this toxic cyanobacterium isolated from Thailand and Japan. All strains shared common morphological traits characteristic of C. raciborskii and showed high 16S rDNA sequence similarity, forming a defined cluster together with the reference strains from Australia. In particular, some of the Thai strains shared 99.9% to 100% similarity with the Australian strains. Various combinations of STRR primers revealed different and unique DNA band patterns among strains of C. raciborskii . The phylogenetic tree revealed two main clusters of C. raciborskii strains, the Thai/Japan‐Shinobazugaike cluster (cluster I) and the Japan‐Gonoike cluster (cluster II). Cluster I was further divided into two subclusters, A (only Thai strains) and B (one Thai strain and the Japan‐Shinobazugaike strains). Thus, the results from 16S rDNA and STRR analyses showed no clear geographical distinction between Japanese and Thai strains and between Thai and Australian strains. Thai strains were separated into adaptive and non‐adaptive groups to low temperature (15 and 17.5 °C) and Japanese strains were composed of only low‐temperature‐adaptive ones. The toxin cylindrospermopsin was detected in some strains of cluster I‐A and in one strain of cluster II. We conclude that C. raciborskii is a species that has recently begun to invade, and a species with different physiological strains or ecotypes in temperature tolerance; the toxin is synthesized without any relation to phylogenetic or genetic clusters and to geography.