Expression and sub-cellular localization of dehydrin-like in wheat leaves under water stress | 水分胁迫下小麦叶片类脱水素表达及亚细胞定位

Chinese. 脱水素(dehydrins)是干旱胁迫逆境响应蛋白之一，为探明水分胁迫下脱水素在细胞的分布及其与耐旱程度的关系，本研究以两种耐旱性不同的冬小麦(Triticum aestivum)为材料，利用胶体金免疫电镜技术及Western blot方法，分析水分胁迫下小麦叶片类脱水素的表达、亚细胞定位，以及与植物抗旱性的关系。结果表明，在胁迫处理初期(4~8 h)金颗粒主要分布在细胞质，细胞核中仅有少量。处理中期(12~24 h)金颗粒主要分布在细胞质和细胞核,细胞器中有少量。后期(36~48 h)大量金颗粒聚集在细胞质膜附近。复水24 h后细胞质和细胞核中金颗粒相对增多。以叶片组织不进行胁迫处理和省却脱水蛋白抗体作对照，几乎未发现金颗粒。随着水分胁迫时间的延长，细胞膜相对透性增大，可溶性蛋白含量上升，有37 kD的脱水素特异表达，其表达量与小麦耐旱性呈正相关，复水后细胞膜相对透性和可溶性蛋白含量下降，脱水素在一段时间内仍存在。该实验为研究小麦叶肉细胞中脱水蛋白的表达和分布提供了直接的证据。

English. Dehydrins is one of the responsive proteins under drought stress. The aim of this study was to explore distribution of dehydrins in cells and the relationship with degree of drought tolerance under water stress. Two different drought resistance winter wheat(Triticum aestivum) as experimental materials，with the colloidal gold immune electron microscopy technique and Western blot, the distribution of sub-cellular structures of dehydrated protein expression in wheat was investigated under water stress, and its relationship with plant drought resistance was also analyzed. The results showed that: At the initial stage of the stress(4~8 h), the golden particles were mainly distributed in the cytoplasm, and also with a small amount in the nucleus; During the interim of the treatment(12~24 h), golden particles were mainly located in the cytoplasm and the nucleus, and also with a small amount in the organelle; At the end of the treatment(36~48 h), most golden particles were detected nearby the plasmalemma; The golden particles in the cytoplasm and the nucleus were relatively more after 24 h of the rehydration; Using the normal leaf tissue without any treatment and default protein antibody as contrast, however, none was detected; With the increase of stress time, the membrane permeability increased at beginning, the soluble protein content was also increased first. Western blotting analysis showed that a specific protein of 37 kD expressed under water stress and its expression was positively correlated with wheat drought tolerance. After rewatering, relative permeability of cell membrane and soluble protein content were all decreased, and dehydrin could exist in plant for some time. In conclusion, these data provide a direct evidence for studying the expression and distribution of the dehydrated protein in wheat mesophyll cell.