Bile Acid Sodium Symporter BASS6 Can Transport Glycolate and Is Involved in Photorespiratory Metabolism in Arabidopsis thaliana[OPEN]
Bile Acid Sodium Symporter BASS6 Can Transport Glycolate and Is Involved in Photorespiratory Metabolism in Arabidopsis thaliana[OPEN]
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DOI：
10.1105/tpc.16.00775
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发表时间：
2017-03
期刊：
影响因子：
11.6
通讯作者：
Paul F. South;Berkley J. Walker;Amanda P. Cavanagh;V. Rolland;M. Badger;Donald R. Ort
中科院分区：
文献类型：
--
作者：
Paul F. South;Berkley J. Walker;Amanda P. Cavanagh;V. Rolland;M. Badger;Donald R. Ort
拟南芥叶绿体定位的BASS6转运蛋白与PLGG1蛋白一起在光呼吸过程中平衡乙醇酸输出和乙醇酸输入。光呼吸是一个能量密集的过程，它循环利用2-磷酸乙醇酸，这是Rubisco氧化反应的有毒产物。光呼吸途径是高度区隔化的，包括叶绿体、过氧化物酶体、细胞质和线粒体。虽然参与光呼吸的可溶性酶已经被很好地表征，但迄今为止，参与光呼吸的膜转运蛋白很少。在这项工作中，含有胆汁酸钠同向转运体BASS6的T-DNA破坏的拟南芥植物在环境下表现出光合作用减少和生长缓慢，但没有升高的二氧化碳。外源表达BASS6补充了这种光呼吸突变表型。此外，酵母中乙醇酸转运的代谢物分析和遗传互补表明，BASS6具有乙醇酸转运的能力。这与它参与拟南芥叶绿体的光呼吸输出乙醇酸是一致的。拟南芥双敲除BASS6和glycolate/glycerate transporter PLGG1 （BASS6, PLGG1）的品系与单突变体相比，表现出了加性生长缺陷、glycolate积累增加和光合速率降低。我们的数据表明，BASS6和PLGG1合作伙伴从叶绿体出口甘油酸，而PLGG1单独负责甘油酸的进口。因此，在光呼吸过程中，BASS6和PLGG1平衡了两个甘油酸分子的输出和一个甘油酸分子的输入。
The chloroplast-localized BASS6 transporter works with the PLGG1 protein to balance glycolate export with glycolate import during photorespiration in Arabidopsis thaliana. Photorespiration is an energy-intensive process that recycles 2-phosphoglycolate, a toxic product of the Rubisco oxygenation reaction. The photorespiratory pathway is highly compartmentalized, involving the chloroplast, peroxisome, cytosol, and mitochondria. Though the soluble enzymes involved in photorespiration are well characterized, very few membrane transporters involved in photorespiration have been identified to date. In this work, Arabidopsis thaliana plants containing a T-DNA disruption of the bile acid sodium symporter BASS6 show decreased photosynthesis and slower growth under ambient, but not elevated CO2. Exogenous expression of BASS6 complemented this photorespiration mutant phenotype. In addition, metabolite analysis and genetic complementation of glycolate transport in yeast showed that BASS6 was capable of glycolate transport. This is consistent with its involvement in the photorespiratory export of glycolate from Arabidopsis chloroplasts. An Arabidopsis double knockout line of both BASS6 and the glycolate/glycerate transporter PLGG1 (bass6, plgg1) showed an additive growth defect, an increase in glycolate accumulation, and reductions in photosynthetic rates compared with either single mutant. Our data indicate that BASS6 and PLGG1 partner in glycolate export from the chloroplast, whereas PLGG1 alone accounts for the import of glycerate. BASS6 and PLGG1 therefore balance the export of two glycolate molecules with the import of one glycerate molecule during photorespiration.