Maier, Ingo, Wolf, Susanne, Delaroque, Nicolas & Müller, Dieter G.
Fakultät für Biologie, Universität Konstanz, D-78457 Konstanz, Germany,
email: Ingo.Maier@uni-konstanz.de
In all brown algal dsDNA viruses investigated so far, the virus genome is intimately associated with the host genome and goes through an extended latency period. Virus propagation is restricted to the presumptive reproductive organs of the host, resulting in infertility. The mechanisms underlying the latency status and activation of virus replication are unknown, but are apparently related to the initiation of sporo- or gametogenesis. In several virus-host systems, infected thalli may partly suppress virus formation and resume formation of normal reproductive cells, thus producing simultaneously virus particles and functional spores or gametes. The ability to suppress virus formation is variable in the different virus-host systems, and most strongly pronounced in heterologous infections. An additional mechanism of escape from virus infection occurs in sexual species like Ectocarpus siliculosus, where the virus genome may be eliminated by Mendelian meiotic segregation. The information available on recovery from virus infections will be summarized and discussed. In addition, a new brown algal DNA virus, the Pilayella littoralis virus (PlitV-1), will be described.