Department of Plant Sciences, University of Hyderabad, Hyderabad, India.
Department of Plant Sciences, University of Hyderabad, Hyderabad, India.
Plant Sci. 2017 Dec;265:12-28. doi: 10.1016/j.plantsci.2017.09.010. Epub 2017 Sep 20.
Annexins belong to a plasma membrane binding (in a calcium dependent manner), multi-gene family of proteins, which play ameliorating roles in biotic and abiotic stresses. The expression of annexin AnnBj2 of Indian mustard is tissue specific with higher expression in roots and under treatments with sodium chloride and abscisic acid (ABA) at seedling stage. The effect of constitutive expression of AnnBj2 in mustard was analyzed in detail. AnnBj2 OE (over expression) plants exhibited insensitivity to ABA, glucose and sodium chloride. The insensitivity/tolerance of the transgenic plants was associated with enhanced total chlorophylls, relative water content, proline, calcium and potassium with reduced thiobarbituric acid reactive substances and sodium ion accumulation. The altered ABA insensitivity of AnnBj2 OE lines is linked to downregulation of ABI4 and ABI5 transcription factors and upregulation of ABA catabolic gene CYP707A2. Furthermore, we found that overexpression of AnnBj2 upregulated the expression of ABA-dependent RAB18 and ABA-independent DREB2B stress marker genes suggesting that the tolerance phenotype exhibited by AnnBj2 OE lines is probably controlled by both ABA-dependent and -independent mechanisms.
annexin 属于质膜结合蛋白（依赖于钙离子）的多基因家族，在生物和非生物胁迫中发挥缓解作用。印度芥菜 annexin AnnBj2 的表达具有组织特异性，在根中表达水平较高，在幼苗期用氯化钠和脱落酸 (ABA) 处理时表达水平更高。详细分析了组成型表达 AnnBj2 对芥菜的影响。AnnBj2 OE（过表达）植株对 ABA、葡萄糖和氯化钠表现出不敏感。转基因植物的不敏感/耐受性与总叶绿素、相对含水量、脯氨酸、钙和钾的增加以及丙二醛反应物质和钠离子积累的减少有关。AnnBj2 OE 系中改变的 ABA 不敏感性与 ABI4 和 ABI5 转录因子的下调以及 ABA 分解代谢基因 CYP707A2 的上调有关。此外，我们发现 AnnBj2 的过表达上调了 ABA 依赖的 RAB18 和 ABA 不依赖的 DREB2B 应激标记基因的表达，这表明 AnnBj2 OE 系表现出的耐受性表型可能受到 ABA 依赖和非依赖机制的控制。
