Significance of xylem translocated sulfate in early responses of stomata to drought in poplar plants

木质部转运硫酸盐在杨树气孔对干旱早期反应中的意义

• 批准号: 215505212
• 负责人: Professor Dr. Heinz Rennenberg
• 金额: --
• 依托单位: Professur für Baumphysiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/215505212?language=en
• 关键词: Significance; xylem; translocated; sulfate; early

Water deficiency, sensed by the root, is supposed to be signaled via xylem transport from the root to the shoot by chemical as well as hydraulic signals. In response to these signals stomatal conductance is reduced to prevent excessive water loss. The chemical signal mostly responsible for stomatal closure in response to drought is thought to be the photohormone abscisic acid (ABA). However, the origin of the ABA involved in this process is still a matter of debate, since it can be synthesized in roots and the shoot. Recent experiments indicated that increasing sulfate concentrations in the xylem constitute an early response to drought; therefore, it has been hypothesized that xylem-borne sulfate accelerates the ABA signal for stomatal closure and that enhanced ABA in the leaves in response to drought does not necessarily originate from synthesis in roots; acceleration of stomatal closure by sulfate is thought to be achieved by activating malate efflux channels of guard cells. To test this hypothesis, (i) mass transport of ABA and sulfate in the xylem, (ii) its sources and the sinks during drought, (iii) drought mediated regulation of expression of sulfate transporters / anion channels, and (iv) the effects of sulfate and ABA on malate efflux from isolated guard cells will be studied. Experiments will be performed with wild type and transgenic poplar lines with altered expression of sulfate transporters, enhanced sulfate use for reduction, and in ABA insensitive mutants.

水分亏缺，感觉到的根，应该是通过木质部运输从根到地上部的化学和水力信号。为了响应这些信号，气孔导度降低，以防止过多的水分损失。光激素脱落酸（阿坝）是气孔关闭的主要化学信号。然而，参与这一过程的阿坝的来源仍然是一个有争议的问题，因为它可以在根和芽中合成。最近的实验表明，木质部中硫酸盐浓度的增加构成了对干旱的早期反应;因此，有人假设木质部中的硫酸盐加速了气孔关闭的阿坝信号，并且响应干旱的叶片中增强的阿坝不一定来源于根中的合成;硫酸盐加速气孔关闭被认为是通过激活保卫细胞的苹果酸流出通道来实现的。为了验证这一假设，（i）质量运输的阿坝和硫酸盐在木质部，（ii）其源和汇在干旱期间，（iii）干旱介导的表达的硫酸盐转运蛋白/阴离子通道的调节，和（iv）硫酸盐和阿坝对苹果酸流出的影响从隔离的保卫细胞将进行研究。实验将与野生型和转基因白杨株系与硫酸盐转运蛋白的表达改变，增强硫酸盐用于还原，并在阿坝不敏感的突变体。

项目成果

Differential expression of specific sulphate transporters underlies seasonal and spatial patterns of sulphate allocation in trees.

特定硫酸盐转运蛋白的差异表达是树木中硫酸盐分配的季节和空间模式的基础

• DOI: 10.1111/pce.12058
• 发表时间: 2013
• 期刊: Plant, cell & environment
• 作者: F. Malcheska;A. Honsel;H. Wildhagen;J. Dürr;C. Larich;H. Rennenberg;C. Herschbach
• 通讯作者: C. Herschbach