Data_Sheet_4_Identification of Genes Preferentially Expressed in Stomatal Guard Cells of Arabidopsis thaliana and Involvement of the Aluminum-Activated Malate Transporter 6 Vacuolar Malate Channel in Stomatal Opening.pdf

Stomatal guard cells (GCs) are highly specialized cells that respond to various stimuli, such as blue light (BL) and abscisic acid, for the regulation of stomatal aperture. Many signaling components that are involved in the stomatal movement are preferentially expressed in GCs. In this study, we identified four new such genes in addition to an aluminum-activated malate transporter, ALMT6, and GDSL lipase, Occlusion of Stomatal Pore 1 (OSP1), based on the expression analysis using public resources, reverse transcription PCR, and promoter-driven β-glucuronidase assays. Some null mutants of GC-specific genes evidenced altered stomatal movement. We further investigated the role played by ALMT6, a vacuolar malate channel, in stomatal opening. Epidermal strips from an ALMT6-null mutant exhibited defective stomatal opening induced by BL and fusicoccin, a strong plasma membrane H+-ATPase activator. The deficiency was enhanced when the assay buffer [Cl–] was low, suggesting that malate and/or Cl– facilitate efficient opening. The results indicate that the GC-specific genes are frequently involved in stomatal movement. Further detailed analyses of the hitherto uncharacterized GC-specific genes will provide new insights into stomatal regulation.

气孔保卫细胞（GCs）是一种高度专业化的细胞，能够对多种刺激，如蓝光（BL）和脱落酸等，产生响应，以调节气孔的开闭。在气孔运动过程中涉及的众多信号成分中，许多优先在GCs中表达。本研究基于对公共资源、反转录PCR和启动子驱动的β-葡萄糖苷酶检测的分析，除铝激活的苹果酸转运蛋白ALMT6和GDSL脂肪酶、气孔孔隙封闭1（OSP1）外，还鉴定出四种新的此类基因。GC特异性基因的某些null突变体表现出气孔运动的变化。我们进一步研究了ALMT6（一种质膜H+-ATPase强激活剂）在气孔开启中的作用。ALMT6基因敲除突变体的表皮条带在蓝光和富马酸诱导下表现出气孔开启缺陷。当检测缓冲液中的[Cl–]含量降低时，这种缺陷加剧，提示苹果酸和/或Cl–有助于气孔的有效开启。研究结果提示GC特异性基因在气孔运动中频繁参与。对迄今为止尚未鉴定的GC特异性基因的进一步详细分析，将为气孔调节提供新的见解。