Key message

Enhanced bioactive JA (JA-Ile) accumulation in OsJAZ9 overexpressing rice helps plants tolerate K deficiency.

Abstract

Potassium (K) represents up to 10% of the plant’s total dry biomass, and its deficiency makes plants highly susceptible to both abiotic and biotic stresses. K shortage results in the inhibition of root and shoots growth, but the underlying mechanism of this response is unclear. Our RNA-Seq and qPCR analysis suggested leading roles for JA pathway genes under K deficiency in rice. Notably, K deficiency and JA application produced similar phenotypic and transcriptional responses. Here, we integrated molecular, physiological and morphological studies to analyze the role of OsJAZ9 in JA homeostasis and K deficiency responses. We raised OsJAZ9 over-expression, knockdown, transcriptional reporter, translational reporter and C-terminal deleted translational reporter lines in rice to establish the role of JA signaling in K ion homeostasis. JA profiling revealed significantly increased JA-Ile levels in OsJAZ9 OE lines under K deficiency. Furthermore, we established that OsJAZ9 overexpression and knockdown result in K deficiency tolerance and sensitivity, respectively, by modulating various K transporters and root system architecture. Our data provide evidence on the crucial roles of OsJAZ9 for improving K deficiency tolerance in rice by altering JA levels and JA responses.

中文翻译：

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OsJAZ9 过表达调节水稻茉莉酸的生物合成和缺钾反应。

关键信息

OsJAZ9 过表达水稻中增强的生物活性 JA (JA-Ile) 积累有助于植物耐受 K 缺乏。

抽象的

钾 (K) 占植物总干生物量的 10%，钾的缺乏使植物对非生物和生物胁迫高度敏感。钾缺乏导致根和芽生长受到抑制，但这种反应的潜在机制尚不清楚。我们的 RNA-Seq 和 qPCR 分析表明 JA 途径基因在水稻缺钾下的主导作用。值得注意的是，K 缺乏和 JA 应用产生了相似的表型和转录反应。在这里，我们整合了分子、生理和形态学研究来分析OsJAZ9在 JA 稳态和 K 缺乏反应中的作用。我们提出了OsJAZ9水稻中的过表达、敲低、转录报告基因、翻译报告基因和 C 端缺失的翻译报告基因系，以确定 JA 信号传导在 K 离子稳态中的作用。JA 分析显示在缺钾条件下OsJAZ9 OE 系中 JA-Ile 水平显着增加。此外，我们通过调节各种 K 转运蛋白和根系结构，确定OsJAZ9过表达和敲低分别导致 K 缺乏耐受性和敏感性。我们的数据提供了关于OsJAZ9通过改变 JA 水平和 JA 反应来提高水稻对 K 缺乏耐受性的关键作用的证据。