Desiccation protects two Antarctic mosses from ultraviolet-B induced DNA damage

J. D. Turnbull, University of Wollongong
S. A. Robinson, University of Wollongong

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This article was originally published as Turnbull, JD & Robinson, SA, Desiccation protects two Antarctic mosses from ultraviolet-B induced DNA damage, Functional Plant Biology, 36, 2009 in press. Original journal information available here

Abstract

Living in a frozen desert, Antarctic mosses are characterised by the ability to survive desiccation and can tolerate multiple desiccation-rehydration events over the summer growing season. As a result of recent ozone depletion, such mosses may also be exposed to ultraviolet-B radiation whilst desiccated. The ultraviolet-B susceptibility of Antarctic moss species was examined in a laboratory experiment that tested whether desiccated or hydrated mosses accumulated more DNA damage under enhanced ultraviolet-B radiation. Accumulation of cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone dimers was measured in moss samples collected from the field and then exposed to ultraviolet-B radiation in either a desiccated or hydrated state. Two cosmopolitan species, Ceratodon purpureus (Hedw.) Brid. and Bryum pseudotriquetrum (Hedw.) Gaertn., B. Mey. & Scherb, were protected from DNA damage when desiccated, with accumulation of cyclobutane pyrimidine dimers reduced by at least 60% relative to hydrated moss. The endemic Schistidium antarctici (Cardot) L.I. Savicz & Smirnova accumulated more DNA damage than the other species and desiccation was not protective in this species. The cosmopolitan species remarkable ability to tolerate high ultraviolet-B exposure, especially in the desiccated state, suggests they may be better able to tolerate continued elevated ultraviolet-B radiation than the endemic species.