Accumulation and polysomal recruitment of transcripts in response to desiccation and rehydration of the moss Tortula ruralis

In a continuing effort to understand vegetative desiccation tolerance in poikilohydric plants we have isolated cDNA clones that represent transcripts involved in the response of the desiccation-tolerant moss Tortula ruralis to desiccation and rehydration. These clones were used in Northern analyses to determine the expression characteristics of the represented transcripts following the desiccation and rehydration of the moss gametophytes. The clones were classified into three groups; hydration, recovery and constitutive, according to their recruitment into polysomal fractions in response to the treatment. The expression characteristics of these clones confirmed the hypothesis that the response of the moss to desiccation and rehydration involves an alteration in the control of translation (at least at the level of transcript recruitment into polysomes). However, this analysis also revealed that changes in the level of transcript accumulation plays an important role in the change in gene expression manifested upon rehydration.