High salinity induces dehydrin accumulation in Chenopodium quinoa Willd. cv. Hualhuas embryos

Chenopodium quinoa can grow at altitudes of 3,600-4,000 masl and is adapted to the highly arid conditions typical of the salty soils in the South American Altiplano, with less than 250 mm of annual rain and temperatures below 0A degrees C. The aim of the study was to investigate the effect of salinity on the dehydrin content of mature embryos harvested from salt-stressed Chenopodium quinoa cv. Hualhuas plants grown at 100 to 500 mM NaCl. To date, no studies exist on the dehydrins of seeds from salt-stressed plants, although dehydrins in the root, stems and leaves have been reported as an adaptation to water deficit produced by salinity. Dehydrin-like protein detection was carried out with an antiserum raised against a highly-conserved lysine-rich 15-amino acid sequence known as the K-segment, which is capable of recognizing proteins immunologically related to the dehydrin family. Dehydrins were analyzed in embryos by both western blot and in situ immunolocalization. Western blot analysis detected at least four dehydrins (55, 50, 34, and 30 kDa) in seeds harvested from quinoa salt-stressed plants treated under a wide range of salinities. The 30 kDa dehydrin increased its accumulation in both 300 and 500 mM NaCl growth conditions as revealed by densitometric analyses. Dehydrin subcellular localization was mostly nuclear at 500 mM of NaCl. A phosphatase treatment of protein extracts caused a mobility shift of the 34 and 30 kDa dehydrin bands suggesting a putative modulation mechanism based on protein phosphorylation. We propose that these novel observations regarding dehydrin accumulation, subcellular localization and phosphorylation state are related to the high salt stress tolerant phenotype previously reported on this cultivar.