ECS1参与调节CO2诱导的拟南芥气孔关闭和H2O2积累

CO2浓度升高可以诱导植物叶片气孔关闭,提高植物对高浓度CO2的适应性.但植物如何感知CO2浓度变化并启动气孔关闭反应的分子机制至今仍不十分清楚.利用高通量、非侵入的远红外成像技术,建立了拟南芥(Arabidopsis thaliana)气孔对CO2浓度变化反应相关的突变体筛选技术,筛选出对环境CO2浓度敏感的拟南芥突变体ecs1.遗传学分析表明,ecs1 为单基因隐性突变体,突变基因ECS1编码一个跨膜钙离子转运蛋白.与野生型拟南芥相比,360 μL·L-1CO2可引起ecs1突变体叶片温度上升和气孔关闭,ecs1突变体对900 μL·L-1CO2长时间处理具有较强的适应性.进一步的实验表明,360 μL·L-1CO2即可诱导ecs1突变体叶片积累较高浓度的H2O2,而900 μL·L-1CO2才能够诱导野生型拟南芥叶片积累H2O2.因此,ECS1可能参与调节高浓度CO2诱导的拟南芥气孔关闭和H2O2产生,H2O2可能作为第二信号分子介导CO2诱导拟南芥气孔关闭的反应.

ECS1 Mediates CO2-induced Stomatal Closure and the Production of H2O2 in Arabidopsis thaliana

Elevating atmospheric CO2 concentration greatly affects global climate changes and the development and production of crops. Stomatal closure can be induced by high concentration CO2 and improves the plant＇s adaptation to elevated levels of atmospheric CO2. However, the mechanism is still unclear. Using infrared thermography, we isolated an Arabidopsis mutant ecsl. Genetic analysis revealed that the mutant is controlled by a single recessive nuclear gene. Map-based cloning revealed that the mutant gene encodes an integral membrane protein that homologizes with calcium transporter. Compared with wild-type Arabidopsis, ecsl showed stomatal closure and increased leaf temperature under 360 μJL.L^1CO2. ecsl had enhanced adaptation to stress of 900 μL.L^1CO2 for a long time. In addition, ecsl produced more H2O2 under 360 μL.L^1CO2 than wild type. Under 900 μL.L-1CO2, both ecsl and wild type produced more H202. Therefore, H202 mediates CO2-induced stomatal closure and is involved in the ECS1 signal pathway in Arabidopsis.