Lysogeny and viral induction of freshwater cyanobacteria in subtropical Australia
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Viral lysis as a result of lysogenic induction has been implicated in the sudden termination of cyanobacteria blooms. However, little is known of the extent of lysogeny in freshwater subtropical cyanobacteria. We induced lysogeny by adding mitomycin C (1 mg/L). In isolates of cyanobacteria, five of eight species lysed, with the decrease in host cells accompanied by a concomitant increase in virus (cyanophage) abundance. In the wild, mitomycin C (1 mg/L) addition induced lysogeny in cyanobacteria in two of six lakes sampled in spring and summer. From our results it appears that lysogeny is a common occurrence in cyanobacteria in subtropical Australia. We have also studied lysogeny in seven strains of the cyanobacteria Cylindrospermopsis raciborskii and present our findings. Cyanobacteria in culture and in the wild co-exist with heterotrophic bacteria, which are generally more abundant and may also be lysogenic. We discuss methods to detect increases in cyanophage when investigating lysogeny in cyanobacteria with associated heterotrophic bacteria, and evaluate the implications of high rates of lysogeny for bloom dynamics.
Aquatic Sciences: Global Changes from the Centre to the Edge
Environmental Science and Management not elsewhere classified