摘要：The interactions between bacteria and algae may play a significant
part in the formation and development of algal blooms. The
bloom-forming cyanobacterium Microcystis occurs mainly as colonial
form in natural waters, and thus it is necessary to study the
interaction between bacteria and colonial Microcystis. This paper
aimed to investigate effects of the cultivable bacteria attached to
Microcystis colonies on the colony size and growth of colonial
Microcystis aeruginosa. Eleven bacterial strains were isolated from
M. aeruginosa colonies collected from Lake Taihu. Among these
bacteria, seven bacterial isolates significantly influenced the colony
size of M. aeruginosa, and four bacterial isolates significantly
influenced the growth rate of M. aeruginosa. Four isolates, related
to the Exiguobacterium, Delftia, Bacillus and Stenotrophomonas,
significantly decreased the colony size of M. aeruginosa by 36-
51%, and two isolates, assigned to the Chryseobacterium and
Pseudomonas chengduensis, significantly increased the M. aeruginosa
colony size by 89% and 63%, respectively, while these isolates
had no effect on the cyanobacterial growth rate. Two
isolates, belonged to the Rheinheimera and Pseudomonas, significantly
decreased the growth rate of M. aeruginosa by 47% and
36%, respectively, and one bacterial strain related to Aeromonas
increased the cyanobacterial growth rate by 22%, while these isolates
had no effect on the cyanobacterial colony size. One isolate
belonged to Sphingomonas was found to significantly increase
the colony size of M. aeruginosa by 80% and significantly
decrease the growth rate of M. aeruginosa by 21%. PCR-denaturing
gradient gel electrophoresis (PCR-DGGE) analysis showed that
all of the bacterial isolates were able to colonize M. aeruginosa
colonies. Our data suggested that the bacteria attached to
Microcystis colonies might influence the cyanobacterial colony size
and growth, and thus influence the formation and development
of Microcystis blooms.
