Phospholipase D (PLD) hydrolyzes membrane lipids to produce phosphatidic acid (PA), a lipid mediator involved in various cellular and physiological processes. Here, we show that PLDα6 and PA regulate the distribution of GIBBERELLIN (GA)-INSENSITIVE DWARF1 (GID1), a soluble gibberellin receptor in rice. PLDα6-knockout (KO) plants display less sensitivity to GA than WT, and PA restores the mutant to a normal GA response. PA binds to GID1, as documented by liposome binding, fat immunoblotting, and surface plasmon resonance. Arginines 79 and 82 of GID1 are two key amino acid residues required for PA binding and also for GID1’s nuclear localization. The loss of PLDα6 impedes GA-induced nuclear localization of GID1. In addition, PLDα6-KO plants attenuated GA-induced degradation of the DELLA protein SLENDER RICE1 (SLR1). These data suggest that PLDα6 and PA positively mediate GA signaling in rice via PA binding to GID1 and promotion of its nuclear translocation.

中文翻译：

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磷脂酶 Dα6 和磷脂酸调节水稻赤霉素信号传导

磷脂酶 D (PLD) 水解膜脂质以产生磷脂酸 (PA)，这是一种参与各种细胞和生理过程的脂质介质。在这里，我们展示了 PLDα6 和 PA 调节赤霉素 (GA)-不敏感 DWARF1 (GID1) 的分布，这是一种水稻中的可溶性赤霉素受体。PLDα6基因敲除 (KO) 植物对 GA 的敏感性低于 WT，并且 PA 将突变体恢复为正常的 GA 反应。PA 与 GID1 结合，如脂质体结合、脂肪免疫印迹和表面等离子共振所证明的那样。GID1 的精氨酸 79 和 82 是 PA 结合和 GID1 核定位所需的两个关键氨基酸残基。PLDα6 的缺失阻碍了 GA 诱导的 GID1 核定位。此外，PLDα6-KO 植物减弱了 GA 诱导的 DELLA 蛋白 SLENDER RICE1 (SLR1) 的降解。这些数据表明，PLDα6 和 PA 通过 PA 与 GID1 结合并促进其核转位，正向介导水稻中的 GA 信号传导。