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

Abstract

Background and Aims Chenopodium quinoa can grow at altitudes of 3,600?4,000 masl and isadapted 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 0°C. The aim of the studywas to investigate the effect of salinity on the dehydrin content of mature embryos harvestedfrom 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 saltstressed plants, although dehydrins in the root, stems and leaves have been reported as an adaptation to water deficit produced by salinity.Methods Dehydrin-like protein detection was carried out with an antiserum raised against a highlyconserved lysine-rich 15-amino acid sequence known as the K-segment, which is capable of recognizing proteins immunologically related to the dehydrin family.Results 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 saltstressed 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 ofNaCl. 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.Conclusions We propose that these novel observations regarding dehydrin accumulation, subcellularlocalization and phosphorylation state are related to the high salt stress tolerant phenotype previously reported on this cultivar.