Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences Urumqi, China.
State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University Harbin, China.
Front Plant Sci. 2015 Feb 10;6:25. doi: 10.3389/fpls.2015.00025. eCollection 2015.
Previously, a bZIP transcription factor from Tamarix hispida, ThbZIP1, was characterized: plants overexpressing ThbZIP1 displayed improved salt stress tolerance but were sensitive to abscisic acid (ABA). In the current study, we further characterized the regulatory network of ThbZIP1 and the mechanism of ABA sensitivity mediated by ThbZIP1. An ABF transcription factor from T. hispida, ThABF1, directly regulates the expression of ThbZIP1. Microarray analysis identified 1662 and 1609 genes that were respectively significantly upregulated or downregulated by ThbZIP1 when exposed to ABA. Gene ontology (GO) analysis showed that the processes including "response to stimulus," "catalytic activity," "binding function," and "metabolic process" were highly altered in ThbZIP1 expressing plants exposed to ABA. The gene expression in ThbZIP1 transformed plants were compared between exposed to ABA and salt on the genome scale. Genes differentially regulated by both salt and ABA treatment only accounted for 9.75% of total differentially regulated genes. GO analysis showed that structural molecule activity, organelle part, membrane-enclosed lumen, reproduction, and reproductive process are enhanced by ABA but inhibited by salt stress. Conversely, immune system and multi-organism process were improved by salt but inhibited by ABA. Transcription regulator activity, enzyme regulator activity, and developmental process were significantly altered by ABA but were not affected by salt stress. Our study provides insights into how ThbZIP1 mediates ABA and salt stress response at the molecular level.
先前，从柽柳中分离到一个 bZIP 转录因子 ThbZIP1，其特性为：过表达 ThbZIP1 的植株表现出增强的耐盐性，但对脱落酸（ABA）敏感。在本研究中，我们进一步研究了 ThbZIP1 的调控网络及其介导 ABA 敏感性的机制。从柽柳中分离到一个 ABF 转录因子 ThABF1，它直接调控 ThbZIP1 的表达。微阵列分析鉴定出 1662 个和 1609 个基因，它们分别在 ABA 胁迫下显著上调或下调。GO 分析表明，包括“对刺激的反应”、“催化活性”、“结合功能”和“代谢过程”在内的过程在 ABA 暴露下的 ThbZIP1 表达植株中发生高度改变。在基因组水平上比较了 ThbZIP1 转化植株在暴露于 ABA 和盐胁迫下的基因表达。仅被盐和 ABA 处理同时调控的基因占总差异表达基因的 9.75%。GO 分析表明，ABA 增强了结构分子活性、细胞器部分、膜封闭腔、生殖和生殖过程，而盐胁迫则抑制了这些过程。相反，盐胁迫增强了免疫系统和多器官过程，而 ABA 则抑制了这些过程。转录调控因子活性、酶调节因子活性和发育过程显著受 ABA 影响，但不受盐胁迫影响。我们的研究提供了 ThbZIP1 在分子水平上如何介导 ABA 和盐胁迫反应的见解。
