Abiotic stresses, including drought and salinity, negatively affect plant development and physiology at molecular and metabolic levels. Sucrose transport, mediating distribution of photosynthates in plant, is a key physiological process impacted by drought and salinity stresses, as sucrose is a prime energy and signaling molecule as well as an osmolyte. Therefore, understanding the effects of abiotic stresses on sucrose transport and transporters, and underlying genetic and molecular mechanisms is imperative to maintain sugar homeostasis in plants under stress. Here, we investigated the effects of drought and salinity stresses on sucrose transport and distribution, and on expression levels of genes encoding SWEET transporters, along with a potential transcription factor regulating SWEET expression in rice. We observed that drought and salinity stresses increased the sucrose content in leaf and root tissues, and in phloem sap of rice indica varieties. Expression analyses of SWEET genes and histochemical analysis of GUS reporter transgenic plants suggested that OsSWEET13 and OsSWEET15 are major SWEET transporters regulating the sucrose transport and levels in response to the abiotic stresses. Transactivation analyses showed that an ABA-responsive transcription factor OsbZIP72 directly binds to the promoters of OsSWEET13 and OsSWEET15, and activates their expression. Taken together, the results showed that the higher expressions of OsSWEET13 and OsSWEET15 genes, induced by binding of an ABA-responsive transcription factor OsbZIP72 to the promoters, potentially modulate sucrose transport and distribution in response to the abiotic stresses. The mechanism could possibly be targeted for maintaining sugar homeostasis in rice under drought and salinity stresses. This article is protected by copyright. All rights reserved.

中文翻译：

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响应干旱和盐胁迫的蔗糖转运涉及水稻中 ABA 介导的 OsSWEET13 和 OsSWEET15 诱导

非生物胁迫，包括干旱和盐分，在分子和代谢水平上对植物发育和生理产生负面影响。蔗糖转运介导植物中光合产物的分布，是受干旱和盐分胁迫影响的关键生理过程，因为蔗糖是主要能量和信号分子以及渗透剂。因此，了解非生物胁迫对蔗糖转运和转运蛋白的影响以及潜在的遗传和分子机制对于维持胁迫下植物的糖稳态势在必行。在这里，我们研究了干旱和盐分胁迫对蔗糖转运和分布的影响，以及对编码 SWEET 转运蛋白的基因表达水平的影响，以及调节水稻中 SWEET 表达的潜在转录因子。我们观察到干旱和盐分胁迫增加了水稻籼稻品种叶片和根组织以及韧皮部汁液中的蔗糖含量。SWEET 基因的表达分析和 GUS 报告基因转基因植物的组织化学分析表明 OsSWEET13 和 OsSWEET15 是主要的 SWEET 转运蛋白，调节蔗糖转运和响应非生物胁迫的水平。反式激活分析表明，ABA 反应性转录因子 OsbZIP72 直接与 OsSWEET13 和 OsSWEET15 的启动子结合，并激活它们的表达。总之，结果表明 OsSWEET13 和 OsSWEET15 基因的更高表达，由 ABA 反应性转录因子 OsbZIP72 与启动子的结合诱导，可能调节蔗糖转运和分布以响应非生物胁迫。该机制可能是在干旱和盐分胁迫下维持水稻糖稳态的目标。本文受版权保护。版权所有。