MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
Qinghai Provincial Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Tibet Plateau, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810008, China.
J Plant Physiol. 2020 Dec;255:153295. doi: 10.1016/j.jplph.2020.153295. Epub 2020 Oct 15.
Arabidopsis NHX5 and NHX6 are endosomal Na,K/H antiporters that function in mediating Na, K and pH homeostasis. Here, we report that NHX5 and NHX6 mediate Li homeostasis in Arabidopsis. We found that the nhx5 nhx6 double mutant was defective in growth and had a high pale rate under Li stress; complementation with either NHX5 or NHX6 restored the growth of the double mutant under LiCl treatments. We further found that CBL3 and CIPK18 collaborate with NHX5 and NHX6 in controlling seedling growth. CBL3 and CIPK18 are involved in the NHX5- and NHX6-mediated response to Li stress but not to salt or low K stress. In addition, NHX5 and NHX6 coordinate NHX8, a plasma membrane antiporter, in mediating Li homeostasis. NHX8 may function differently from NHX5 and NHX6 in mediating Li homeostasis. NHX8 was not controlled by CBL3 and CIPK18. Overall, CBL3 and CIPK18 are required for the function of NHX5 and NHX6 in mediating Li homeostasis in Arabidopsis.
拟南芥 NHX5 和 NHX6 是内体 Na,K/H 反向转运蛋白，可介导 Na、K 和 pH 平衡。在这里，我们报告 NHX5 和 NHX6 介导拟南芥中的 Li 平衡。我们发现 nhx5 nhx6 双突变体在 Li 胁迫下生长缺陷，且 pale 率较高；NHX5 或 NHX6 的互补恢复了 nhx5 nhx6 双突变体在 LiCl 处理下的生长。我们进一步发现 CBL3 和 CIPK18 与 NHX5 和 NHX6 合作控制幼苗生长。CBL3 和 CIPK18 参与 NHX5 和 NHX6 介导的对 Li 胁迫的反应，但不参与盐或低钾胁迫的反应。此外，NHX5 和 NHX6 与质膜反向转运蛋白 NHX8 协调，共同介导 Li 平衡。NHX8 在介导 Li 平衡方面的功能可能与 NHX5 和 NHX6 不同。NHX8 不受 CBL3 和 CIPK18 的控制。总的来说，CBL3 和 CIPK18 是 NHX5 和 NHX6 介导拟南芥 Li 平衡所必需的。
