OsPUB67, a U-box E3 ubiquitin ligase, may interact with two drought tolerance negative regulators (OsRZFP34 and OsDIS1) and improve drought tolerance by enhancing the reactive oxygen scavenging ability and stomatal closure. E3 ubiquitin ligases are major components of the ubiquitination cascade and contribute to the biotic and abiotic stress response in plants. In the present study, we show that a rice drought responsive gene, OsPUB67, encoding the U-box E3 ubiquitin ligase was significantly induced by drought, salt, cold, JA, and ABA, and was expressed in nuclei, cytoplasm, and membrane systems. This distribution of expression suggests a significant role for OsPUB67 in a wide range of biological processes and abiotic stress response. Over-expression of OsPUB67 improved drought stress tolerance by enhancing the reactive oxygen scavenging ability and stomatal closure. Bimolecular fluorescence complementation assays revealed that a few E2s interacted with OsPUB67 with unique functional implications in different cell components. Further evidence showed that several E3 ubiquitin ligases interacted with OsPUB67, especially OsRZFP34 and OsDIS1, which are negative regulators of drought tolerance. This interaction on the stomata implied OsPUB67 might function as a heterodimeric ubiquitination complex in response to drought stress. Comprehensive transcriptome analysis revealed OsPUB67 participated in regulating genes involved in the abiotic stress response and transcriptional regulation in an ABA-dependent manner. Our findings revealed OsPUB67 mediated a multilayered complex drought stress tolerance mechanism.

中文翻译：

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U-box E3 泛素连接酶 OsPUB67 正参与水稻的耐旱性。

OsPUB67 是一种 U-box E3 泛素连接酶，可能与两个耐旱负调节因子（OsRZFP34 和 OsDIS1）相互作用，通过增强活性氧清除能力和气孔关闭来提高耐旱性。E3 泛素连接酶是泛素化级联反应的主要成分，有助于植物的生物和非生物胁迫反应。在本研究中，我们发现编码 U-box E3 泛素连接酶的水稻干旱响应基因 OsPUB67 受到干旱、盐、寒冷、JA 和 ABA 的显着诱导，并在细胞核、细胞质和膜系统中表达。 . 这种表达分布表明 OsPUB67 在广泛的生物过程和非生物胁迫反应中发挥着重要作用。OsPUB67 的过表达通过增强活性氧清除能力和气孔关闭来提高干旱胁迫耐受性。双分子荧光互补分析表明，一些 E2 与 OsPUB67 相互作用，在不同的细胞成分中具有独特的功能意义。进一步的证据表明，几种 E3 泛素连接酶与 OsPUB67 相互作用，尤其是 OsRZFP34 和 OsDIS1，它们是耐旱性的负调控因子。气孔上的这种相互作用暗示 OsPUB67 可能作为异二聚体泛素化复合物响应干旱胁迫。综合转录组分析表明，OsPUB67 以 ABA 依赖性方式参与调控非生物胁迫反应和转录调控的基因。