Plant Biotechnology Research Center, School of Agriculture and Life Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China.
Plant Biotechnology Research Center, School of Agriculture and Life Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China.
Biochem Biophys Res Commun. 2020 Nov 26;533(1):104-109. doi: 10.1016/j.bbrc.2020.08.025. Epub 2020 Sep 12.
NRT1.2 has been characterized as a low-affinity nitrate transporter and an abscisic acid (ABA) transporter in Arabidopsis. In this study, we demonstrate that NRT1.2 positively regulated the ABA response during germination and seedling development. The transgenic Arabidopsis NRT1.2-over-expressionors showed increased sensitivity to ABA during these processes. qRT-PCR assays indicated that NRT1.2 over-production in 7-days-old seedlings up-regulated the expression of ABA-responsive genes: ABI1, ABI2, ABI3, ABI4, ABI5, RAB18, RD29A, and RD29B and PHOSPHOLIPASE Dα1 (PLDα1). The expression of these genes was suppressed in the nrt1.2 mutant in comparison with the wild type following ABA treatment. Importantly, bimolecular fluorescence complementation assays indicated that NRT1.2 interacts with PLDα1 at the plasma membrane. Their interaction was further confirmed by using yeast two hybrid (Y2H) experiments with the mating-based split ubiquitin system (MbSUS). Moreover, genetic assays indicated that PLDα1 acts epistatically on NRT1.2 to affect ABA signaling. Taken together, our results provide detailed mechanisms of NRT1.2 in ABA-mediated seed germination and seedling development.
NRT1.2 已被鉴定为拟南芥中低亲和力硝酸盐转运体和脱落酸（ABA）转运体。在这项研究中，我们证明了 NRT1.2 在萌发和幼苗发育过程中正向调节 ABA 反应。转基因拟南芥 NRT1.2 过表达植株在这些过程中对 ABA 表现出更高的敏感性。qRT-PCR 分析表明，7 天大的幼苗中 NRT1.2 的过度表达上调了 ABA 响应基因的表达：ABI1、ABI2、ABI3、ABI4、ABI5、RAB18、RD29A 和 RD29B 以及 PHOSPHOLIPASE Dα1（PLDα1）。与野生型相比，ABA 处理后 nrt1.2 突变体中这些基因的表达受到抑制。重要的是，双分子荧光互补测定表明 NRT1.2 在质膜上与 PLDα1 相互作用。利用交配型分裂泛素系统（MbSUS）的酵母双杂交（Y2H）实验进一步证实了它们的相互作用。此外，遗传分析表明 PLDα1 在 NRT1.2 上表现出上位性，以影响 ABA 信号。总之，我们的结果提供了 NRT1.2 在 ABA 介导的种子萌发和幼苗发育中的详细作用机制。
