Multiple plasma membrane SLC4s contribute to external HCO3- acquisition during CO2 starvation in the marine diatom Phaeodactylum tricornutum
Multiple plasma membrane SLC4s contribute to external HCO3- acquisition during CO2 starvation in the marine diatom Phaeodactylum tricornutum
复制标题
海洋硅藻三角褐指藻在 CO2 饥饿期间，多个质膜 SLC4 有助于获取外部 HCO3-
DOI：
10.1093/jxb/erac380
复制
发表时间：
2022
影响因子：
6.9
通讯作者：
Matsuda Yusuke
中科院分区：
文献类型：
--
作者：
Nawaly Hermanus;Matsui Hiroaki;Tsuji Yoshinori;Iwayama Kazufumi;Ohashi Hiroki;Nakajima Kensuke;Matsuda Yusuke
CO2的可利用性是限制水生植物光合作用的主要因素之一。溶质载体（SLC）4-2，质膜HCO 3-转运蛋白先前已被确定在海洋三角褐指藻。在这项研究中，我们发现了两个旁系同源物，PtSLC 4 -1和PtSLC 4 -4，都定位于质膜。它们的过表达刺激HCO 3-摄取，这被阴离子通道阻断剂4，4 ′-二异硫氰基芪-2，2 ′-二磺酸（DIDS）抑制。与SLC 4 -2相似，PtSLC 4 -1特异性地需要约100 mM的Na+才能实现其最大HCO 3-转运活性。与PtSLC 4 -1和PtSLC 4 -2不同，PtSLC 4 -4的HCO 3-转运同样依赖于Na+、K+或Li+，这表明其对阳离子的广泛选择性。转录分析表明，PtSLC 4 -1在低于大气CO2浓度下是最丰富的HCO 3-转运蛋白，而PtSLC 4 -4在大气CO2下几乎没有转录诱导，但在从高CO2（1%）到极低CO2（<0.002%）的初始驯化阶段短暂诱导到与PtSLC 4 -1相当的水平。我们的研究结果强烈表明，一个主要的HCO 3-运输的PtSLC 4 -1的作用与PtSLC 4 -2的相对较小的作用，和PtSLC 4 -4在严重的CO2限制下操作时，其他SLC 4不支持HCO 3-摄取的阳离子无选择性。
The availability of CO2is one of the restrictions on aquatic photosynthesis. Solute carrier (SLC) 4-2, a plasma membrane HCO3–transporter has previously been identified in the marine diatomPhaeodactylum tricornutum. In this study, we discovered two paralogs, PtSLC4-1 and PtSLC4-4, that are both localized at the plasma membrane. Their overexpression stimulated HCO3–uptake, and this was inhibited by the anion channel blocker 4,4´-diisothiocyanostilbene-2,2´-disulfonic (DIDS). Similarly to SLC4-2, PtSLC4-1 specifically required Na+of ~100 mM for its maximum HCO3–transport activity. Unlike PtSLC4-1 and PtSLC4-2, the HCO3–transport of PtSLC4-4 depended equally on Na+, K+, or Li+, suggesting its broad selectivity for cations. Transcript analyses indicated that PtSLC4-1 was the most abundant HCO3–transporter under CO2concentrations below atmospheric levels, while PtSLC4-4 showed little transcript induction under atmospheric CO2but transient induction to comparable levels to PtSLC4-1 during the initial acclimation stage from high CO2(1%) to very low CO2(<0.002%). Our results strongly suggest a major HCO3–transport role of PtSLC4-1 with a relatively minor role of PtSLC4-2, and that PtSLC4-4 operates under severe CO2limitation unselectively to cations when the other SLC4s do not function to support HCO3–uptake.