Open AccessDynamics of microcystin‐producing and non‐microcystin‐producing Microcystis populations is correlated with nitrate concentration in a Japanese lake
Author(s) -
Yoshida Mitsuhiro,
Yoshida Takashi,
Takashima Yukari,
Hosoda Naohiko,
Hiroishi Shingo
Publication year - 2007
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2006.00496.x
Subject(s) - microcystin , microcystis aeruginosa , microcystis , phycocyanin , nitrate , biology , hepatotoxin , cyanobacteria , population , microbiology and biotechnology , ecology , medicine , bacteria , toxicity , genetics , environmental health
Temporal changes in hepatotoxin microcystin‐producing and non‐microcystin‐producing Microcystis aeruginosa populations were examined in Lake Mikata, Japan. To monitor the densities of the total M. aeruginosa population and the potential microcystin‐producing subpopulation, we used a quantitative real‐time PCR assay targeting the phycocyanin intergenic spacer and the microcystin synthetase gene ( mcyA ), respectively. During the sampling period, the ratio of the mcyA subpopulation to the total M. aeruginosa varied considerably, from 0.5% to 35%. When surface nitrate concentrations increased, there was a rise in the relative abundance of the mcyA subpopulation. This was a positive correlation with the nitrate concentrations ( r =0.53, P <0.05, n =14); whereas temperature and ortho‐phosphate had no significant correlation with the presence of mcyA . Our data suggest that high nitrate loading may be a significant factor promoting the growth of the microcystin subpopulations within M. aeruginosa communities in Lake Mikata.