National Key Facility for Crop Genetic Resources and Genetic Improvement (NFCRI), Key Laboratory of Crop Genetics and Breeding, Ministry of Agriculture, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China.
Plant Mol Biol. 2011 Apr;75(6):537-53. doi: 10.1007/s11103-011-9738-4. Epub 2011 Feb 18.
Abscisic acid (ABA)-responsive element binding proteins (AREBs) are basic domain/leucine zipper transcription factors that bind to the ABA-responsive element (ABRE) in the promoter regions of ABA-inducible genes in plants. A novel bZIP transcription factor gene, GmbZIP1, encoding 438 amino acids with a conserved bZIP domain composed of 60 amino acids was isolated from salt-tolerant soybean cv. Tiefeng 8. Southern blotting showed that only one copy was present in the soybean genome. Phylogenetic analyses showed that GmbZIP1 belonged to the AREB subfamily of the bZIP family and was most closely related to AtABF2 and OsTRAB1. The expression of GmbZIP1 was highly induced by ABA, drought, high salt and low temperature; and GmbZIP1 was expressed in soybean roots, stems and leaves under different stress conditions. GmbZIP1 was localized inside the nuclei of transformed onion epidermal cells. Overexpression of GmbZIP1 enhanced the responses of transgenic plants to ABA and triggered stomatal closure under stresses, potentially leading to improved tolerances to several abiotic stresses such as high salt, low temperature and drought in transgenic plants. Furthermore, overexpression of GmbZIP1 affected the expression of some ABA or stress-related genes involved in regulating stomatal closure in Arabidopsis under ABA, drought and high salt stress conditions. A few AREB elements were detected in the promoter region of those ABA or stress-related genes, suggesting that GmbZIP1 regulates the ABA response or stomatal closure mediated by those downstream genes in transgenic Arabidopsis. Moreover, GmbZIP1 was used to improve the drought tolerance trait of Chinese wheat varieties BS93. Functional analysis showed that overexpression of GmbZIP1 enhanced the drought tolerance of transgenic wheat, and transcripts of GmbZIP1 were detected in transgenic wheat using RT-PCR. In addition, GmbZIP1 overexpression did not result in growth retardation in all transgenic plants, suggesting that GmbZIP1 may be a valuable genetic resource for engineering stress tolerance of crops.
脱落酸（ABA）响应元件结合蛋白（AREB）是碱性区域/亮氨酸拉链转录因子，它们与植物中 ABA 诱导基因启动子区域中的 ABA 响应元件（ABRE）结合。从耐盐大豆品种 Tiefeng 8 中分离到一个新的 bZIP 转录因子基因 GmbZIP1，其编码 438 个氨基酸，包含一个由 60 个氨基酸组成的保守 bZIP 结构域。Southern 印迹分析表明，大豆基因组中只有一个拷贝。系统进化分析表明，GmbZIP1 属于 bZIP 家族的 AREB 亚家族，与 AtABF2 和 OsTRAB1 最为密切相关。ABA、干旱、高盐和低温均能强烈诱导 GmbZIP1 的表达；在不同胁迫条件下，GmbZIP1 在大豆根、茎和叶中表达。GmbZIP1 定位于转化洋葱表皮细胞的细胞核内。过表达 GmbZIP1 增强了转基因植物对 ABA 的响应，并在胁迫下引发气孔关闭，可能导致转基因植物对高盐、低温和干旱等多种非生物胁迫的耐受性提高。此外，过表达 GmbZIP1 影响了拟南芥在 ABA、干旱和高盐胁迫条件下一些与 ABA 或胁迫相关的基因的表达，这些基因参与调控气孔关闭。在这些与 ABA 或胁迫相关的基因的启动子区域检测到一些 AREB 元件，表明 GmbZIP1 调节转基因拟南芥中这些下游基因介导的 ABA 响应或气孔关闭。此外，利用 GmbZIP1 改良中国小麦品种 BS93 的耐旱性。功能分析表明，过表达 GmbZIP1 增强了转基因小麦的耐旱性，并用 RT-PCR 检测到了转基因小麦中的 GmbZIP1 转录本。此外，在所有转基因植物中，GmbZIP1 的过表达并没有导致生长迟缓，这表明 GmbZIP1 可能是作物耐逆性工程的宝贵遗传资源。
