Functional roles of ALMT‐type anion channels in malate‐induced stomatal closure in tomato and Arabidopsis
Functional roles of ALMT‐type anion channels in malate‐induced stomatal closure in tomato and Arabidopsis
复制标题
ALMT型阴离子通道在番茄和拟南芥苹果酸诱导气孔关闭中的功能作用
DOI：
10.1111/pce.14373
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Mori Izumi C.
中科院分区：
文献类型：
--
作者：
Sasaki Takayuki;Ariyoshi Michiyo;Yamamoto Yoko;Mori Izumi C.
保卫细胞型铝激活的苹果酸转运蛋白（ALMT）通过从保卫细胞输出阴离子参与气孔关闭。然而，它们的生理和电生理功能尚未被探索。本文分析了拟南芥和番茄ALMT通道的生理和电生理特性，结果表明SlALMT 11在番茄保卫细胞中特异表达。外源苹果酸诱导的气孔关闭在番茄和拟南芥的ALMT抑制株系中受损，尽管脱落酸不影响SlALMT 11敲低番茄株系的气孔反应。对异种卵母细胞的电生理分析表明，SlALMT 11和AtALMT 12/QUAC 1表现出依赖于细胞外苹果酸、富马酸和柠檬酸的特征性钟形电流-电压模式。两种ALMT都可以转运苹果酸、富马酸和琥珀酸，但不能转运柠檬酸，这表明保卫细胞型ALMT是由细胞外有机酸激活的二羧酸阴离子通道。从SlALMT 11或AtALMT 12/QUAC 1的C末端截短酸性氨基酸Asp或Glu导致钟形电流-电压模式消失。我们的研究结果表明，苹果酸激活的气孔关闭是由保卫细胞型ALMT通道介导的，该通道在番茄和拟南芥中都需要C末端的酸性氨基酸作为候选电压传感器。
Guard‐cell‐type aluminium‐activated malate transporters (ALMTs) are involved in stomatal closure by exporting anions from guard cells. However, their physiological and electrophysiological functions are yet to be explored. Here, we analysed the physiological and electrophysiological properties of the ALMT channels in Arabidopsis and tomato (Solanum lycopersicum).SlALMT11was specifically expressed in tomato guard cells. External malate‐induced stomatal closure was impaired inALMT‐suppressed lines of tomato and Arabidopsis, although abscisic acid did not influence the stomatal response inSlALMT11‐knock‐down tomato lines. Electrophysiological analyses inXenopusoocytes showed that SlALMT11 and AtALMT12/QUAC1 exhibited characteristic bell‐shaped current‐voltage patterns dependent on extracellular malate, fumarate, and citrate. Both ALMTs could transport malate, fumarate, and succinate, but not citrate, suggesting that the guard‐cell‐type ALMTs are dicarboxylic anion channels activated by extracellular organic acids. The truncation of acidic amino acids, Asp or Glu, from the C‐terminal end of SlALMT11 or AtALMT12/QUAC1 led to the disappearance of the bell‐shaped current‐voltage patterns. Our findings establish that malate‐activated stomatal closure is mediated by guard‐cell‐type ALMT channels that require an acidic amino acid in the C‐terminus as a candidate voltage sensor in both tomato and Arabidopsis.