Abstract:

Water channels or aquaporins are the main pathways of water transport. Both the existence and function of aquaporins in the guard cells of Vicia faba L. were investigated both by using RD28 cDNA and RD28 antibody as probes, and by controlling stomatal movement as a parameter combined with antibody and inhibitor of aquaporins respectively. The results revealed that RD28 mRNA, encoding a plasma membrane aquaporin, expressed in the mesophyll cells and vascular tissues of V． faba, especially in guard cells. And the location of RD28-like proteins was mainly on plasma membrane of guard cells. The addition of 25　μmol/L HgCl2, an aquaporin blocker, and antibody of RD28 as well, greatly suppressed the stomatal opening or guard-cell protoplast swelling induced by fusicoccin and light, and closing induced by abscisic acid. However, 5 mmol/L β-mercaptoethanol, a reverse reagent of aquaporin blocker, reversed the inhibitory effect of HgCl2 pretreatment on stomatal opening (i.e., HgCl2 was removed after HgCl2 pretreatment for 10 min). The results suggest that the aquaporins in V. faba are associated with stomatal movement.

蚕豆保卫细胞质膜水通道蛋白的鉴定及其在气孔运动中的作用

黄荣峰^1,3  朱美君^2,3  康蕴²  陈珈^2,3  王学臣^2,3*

(1. 中国农业科学院生物技术研究所,北京 100081; 2. 中国农业大学生物学院,北京 100094; 3. 植物生理学与生物化学国家重点实验室,北京 100094)

摘要：水通道或水通道蛋白是水分运动的主要通道.以RD28 cDNA和RD28抗体为探针证明了蚕豆(Vicia faba L.)保卫细胞中存在水通道蛋白,并以气孔运动为指标,结合抗体和抑制剂处理证明水通道蛋白是水分运动的主要通道.研究表明编码质膜水通道蛋白的RD28转录体在叶片保卫细胞、叶肉细胞和维管束中高表达,尤以保卫细胞中最多;荧光免疫染色和Confocal显微镜观察表明,RD28抗体反应主要位于保卫细胞质膜.进一步采用RD28抗体和水通道蛋白抑制剂--HgCl₂ (25μmol/L)处理可抑制壳梭孢素(FC)、光照诱导的气孔开放和原生质体体积膨胀以及ABA诱导的气孔关闭,但这种抑制作用可以被水通道抑制剂的逆转剂β-巯基乙醇(ME)逆转.表明蚕豆保卫细胞中存在水通道蛋白并参与蚕豆保卫细胞的运动过程.

关键词 水通道蛋白 原位杂交 RD28抗体 气孔运动 蚕豆

*通讯作者 E-mail: xcwang@public.bta.net.cn

Key words: aquaporin, in situ hybridization, antibody of RD28, stomatal movement, Vicia faba