Kiyosue T, Yamaguchi-Shinozaki K, Shinozaki K
Laboratory of Plant Molecular Biology, Tsukuba Life Science Center, Ibaraki, Japan.
Plant Mol Biol. 1994 Aug;25(5):791-8. doi: 10.1007/BF00028874.
In Arabidopsis thaliana L., accumulation of abscisic acid (ABA) began to increase 2 h after plants had been subjected to dehydration stress and reached maximum levels after 10 h. Differential hybridization was used to isolate 26 Arabidopsis cDNAs with gene expression induced by a 1 h dehydration treatment. The cDNA clones were classified into 16 groups based on Southern blot hybridization, and named ERD (early-responsive to dehydration) clones. Partial sequencing of the cDNA clones revealed that three ERDs were identical to those of HSP cognates (Athsp70-1, Athsp81-2, and ubiquitin extension protein). Dehydration stress strongly induced the expression of genes for the three ERDs, while application of ABA, which is known to act as a signal transmitter in dehydration-stressed plants, did not significantly affect the ERD gene expression. This result suggests that these HSP cognates are preferentially responsive to dehydration stress in A. thaliana, and that signaling pathways for the expression of these genes under conditions of dehydration stress are not mainly mediated by ABA. We also discuss the possible functions of these three ERD gene products against dehydration stress.
在拟南芥中，脱落酸（ABA）的积累在植株遭受脱水胁迫2小时后开始增加，并在10小时后达到最高水平。利用差异杂交技术分离出26个受1小时脱水处理诱导基因表达的拟南芥cDNA。根据Southern杂交结果，这些cDNA克隆被分为16组，并命名为ERD（脱水早期响应）克隆。对这些cDNA克隆进行部分测序发现，其中三个ERD与热激蛋白同源物（Athsp70-1、Athsp81-2和泛素延伸蛋白）的序列相同。脱水胁迫强烈诱导这三个ERD基因的表达，而在脱水胁迫植株中作为信号传递分子的ABA的施用对ERD基因表达没有显著影响。这一结果表明，这些热激蛋白同源物在拟南芥中优先响应脱水胁迫，并且在脱水胁迫条件下这些基因表达的信号通路并非主要由ABA介导。我们还讨论了这三个ERD基因产物对抗脱水胁迫的可能功能。
