Seedling survival after desiccation when rehydrated with NaCl solutions, in some annual and perennial desert halophytes
South African Journal of Botany
protein of approx. 14 kDa, and this has been designated as a putative storage protein (JR14). Other stress-related proteins (dehydrins and smHSPs), which are often associated with tolerance of water deficits also increase. SDS-PAGE analysis of roots at all stages of the R. asciaticus life cycle revealed that JR14 accumulates during the desiccation period, and two-dimensional electrophoresis demonstrated that there are, in fact, two major proteins of around 14 kDa. One of these was purified, and
... e was purified, and the first 31 N-terminal amino acids were determined by sequencing. A 489 bp full length JR14 cDNA sequence was obtained by 3′-RACE and 5′-RACE PCR using oligonucleotide sequences based on the terminal amino acids. The amino acid sequence (163 amino acids) of the JR14 protein shows that it has stress-induced domains PLAT/LH2. A peptide of 24 N-terminal amino acids of the full length JR14 protein is a possible signal peptide, indicative that it is a sequestered protein. It has no strong similarity with known water-stress-related proteins, nor with the low mol. mass storage protein present in the tap roots of dandelion. Western blots indicated that the expression of dehydrin Dhn4B (LEAII D-11 family) is induced by dehydration and ABA, and declines during rehydration. The cDNA sequence of Dhn4B has a very high similarity with dehydrins known in other species. As with dehydrins, smHSPs were also detected by western blots in the tuberous roots during desiccation, and their expression was induced by high temperature and dehydration.