DEHYDRATION STRESS-INDUCED CHANGES IN TRANSLATABLE RNAS IN SORGHUM

Sorghum [Sorghum bicolor (L.) Moench] is a drought-resistant crop species. The main objective of this work was to study the dehydration stress induced changes in mRNA accumulation in sorghum. Ten-day-old seedlings were dried in a closed chamber for 6, 10, 14, 18, and 22 h. Poly(A)(+) RNAs, isolated from control and dehydration-stressed shoots, were translated in vitro in the presence of S-35 methionine and the translation products were separated by two-dimensional polyacrylamide gel electrophoresis. Four types of polypeptides which exhibited significant changes during the time course were distinguished. Northern blot analysis using a cDNA encoding a dehydration-induced protein (dehydrin) revealed a rapid induction and increased accumulation of dehydrin mRNA species throughout the drought stress process, These results suggest that sorghum seedlings, similar to other plant species, exhibit altered gene expression patterns in response to the length of drought stress period.