RACK1蛋白调控拟南芥干旱胁迫应答的功能研究

干旱是植物面临的主要胁迫之一，其在全球范围内极大影响了农作物的生长和产量。为此，研究发掘抗旱基因是培育抗旱作物的重要基础。本文主要研究了RACK1蛋白在拟南芥中的耐旱功能和调控机制。

在拟南芥中，RACK1蛋白是一种关键的受体支架蛋白。本研究表明，RACK1蛋白在拟南芥抗旱响应中发挥着重要功能。通过对野生型Col-0、突变体rack1a、rack1abc和过表达转基因株系GFP-RACK1A #6、GFP-RACK1A #17这5种遗传材料进行干旱胁迫处理，其表型分析表明rack1突变体的耐旱能力显著增强，在极度干旱胁迫条件下仍然具有较高的存活率，并表现出了较强的干旱胁迫恢复能力。通过观察统计这5种rack1基因型拟南芥幼苗的叶片失水表型，以及利用光合仪测定它们的各项植物生理参数，如叶绿素荧光Fv/Fm、气孔导度和净光合速率，结果表明rack1突变体通过降低叶片蒸腾速率，从而提高耐旱性和存活率。此外，测定不同干旱处理时期的拟南芥幼苗地上部组织的ABA含量，以及分析甘露醇或ABA诱导处理下的气孔特性，结果表明RACK1蛋白功能缺失导致抑制植物叶片的气孔发育，并通过参与调控ABA生物合成途径，促进干旱胁迫条件下叶片气孔的闭合。为了探究RACK1在拟南芥地下部的作用机制，对5种rack1基因型拟南芥的根部进行了甘露醇模拟干旱胁迫处理，并检测了植株根部组织中15种水孔蛋白的基因表达量，这些结果表明RACK1蛋白主要通过调控根系生长，进而提高拟南芥植株的耐旱能力。

综上所述，拟南芥RACK1蛋白作用于植物地上部和地下部，参与调控植物的耐旱性。rack1突变体优于野生型和过表达转基因材料的各项耐旱结果也表明了RACK1是拟南芥耐旱性的负调控因子。

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