Messenger RNA is conserved during drying of the drought-tolerant moss Tortula ruralis

On rehydration after complete drying, the drought-tolerant moss Tortula ruralis (Hedw.) Gaertn., Meyer, and Scherb reforms its polyribosomes and can resume protein synthesis without new RNA synthesis. Results obtained with the double-label ratio technique coupled with polyacrylamide disc gel electrophoresis show that (i) the proteins synthesized on rehydration are largely similar to those synthesized at the time of dehydration and (ii) inhibition of RNA synthesis does not alter the rate or the pattern of protein synthesis during rehydration of slowly dried moss. Poly(A)-rich RNA has been isolated from fresh and dried moss by chromatography on oligo(dT)-cellulose and has been translated in vitro in the cell-free wheat germ system. It is concluded that mRNA is conserved during complete drying of T. ruralis and supports protein synthesis on subsequent rehydration. This ability to conserve mRNA is a characteristic held in common by vegetative drought-tolerant tissue of T. ruralis and air-dried seeds of higher plants.