DYNAMICS OF MICROCYSTIS-INFECTING CYANOPHAGES IN TROPICAL FRESHWATERS THROUGH QPCR AND NEXT GENERATION SEQUENCING

Cyanophages (i.e. viruses that infect cyanobacteria) are crucial in regulating the abundance of their host cells, affecting the clonal diversity as well as the composition of the cyanobacterial community. This thesis focuses on two environmental water studies based on short- (72-hour diel cycle) and long- (2 years monthly monitoring) term sampling events in different freshwater systems around Singapore. In both studies, there are two approaches, (1) to focus on Microcystis cyanobacteria and its associated Ma-LMM01-type cyanophages and (2) to use Next-Generation Sequencing (NGS) to further our understanding on the viral community and diversity. Results from this thesis study showed the influence of environmental variables (monsoon seasons) on predator-prey dynamics and leveraged on NGS to circumvent the lack of established molecular assays for the quantification of cyanophages to gain an overview on the diversity and dynamics of the viral community in tropical freshwaters.

Author dc:creator

• LOH LAY LENG

• cyanophages, viruses, next generation sequencing, qPCR, cyanobacteria, algal blooms