Biodiversity and seasonal variation of the cyanobacterial assemblage in a rice paddy field in Fujian, China.

Cyanobacteria are one of the main components of the microbiota in rice paddy fields and significantly contribute to its fertilization. The diversity and changes of the cyanobacterial assemblage were investigated during a rice growth season and after harvest in a paddy field located in Fujian Province, China. The cyanobacterial populations were analyzed by a semi-nested PCR, followed by denaturing gradient gel electrophoresis analysis. Twenty-four phylotypes were identified from the denaturing gradient gel electrophoresis profiles. The number of cyanobacterial phylotypes showed a seasonal variation and reached a peak in September, both in the upper (0-5 cm) and the deeper (10-15 cm) soil fractions. Some cyanobacterial sequences were only present during the rice growth season, while others were only found after harvest.