title: S-type Anion Channels SLAC1 and SLAH3 Function as Essential Negative Regulators of Inward K+ Channels and Stomatal Opening in Arabidopsis.
abstract: Drought stress induces stomatal closure and inhibits stomatal opening simultaneously. However, the underlying molecular mechanism is still largely unknown. Here we show that S-type anion channels SLAC1 and SLAH3 mainly inhibit inward K+ (K+in) channel KAT1 by protein-protein interaction, and consequently prevent stomatal opening in Arabidopsis. Voltage-clamp results demonstrated that SLAC1 inhibited KAT1 dramatically, but did not inhibit KAT2. SLAH3 inhibited KAT1 to a weaker degree relative to SLAC1. Both the N terminus and the C terminuses of SLAC1 inhibited KAT1, but the inhibition by the N terminus was stronger. The C terminus was essential for the inhibition of KAT1 by SLAC1. Furthermore, drought stress strongly up-regulated the expression of SLAC1 and SLAH3 in Arabidopsis guard cells, and the over-expression of wild type and truncated SLAC1 dramatically impaired K+in currents of guard cells and light-induced stomatal opening. Additionally, the inhibition of KAT1 by SLAC1 and KC1 only partially overlapped, suggesting that SLAC1 and KC1 inhibited K+in channels using different molecular mechanisms. Taken together, we discovered a novel regulatory mechanism for stomatal movement, in which singling pathways for stomatal closure and opening are directly coupled together by protein-protein interaction between SLAC1/SLAH3 and KAT1 in Arabidopsis.
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences CITY: Shanghai STATE: Shanghai China [CN].
authors.forename: An
authors.initials: A
authors.lastname: Zhang
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences CITY: Shanghai STATE: Shanghaic China [CN].
authors.forename: Hui-Min
authors.initials: HM
authors.lastname: Ren
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences CITY: Shanghai STATE: Shanghaic China [CN].
authors.forename: Yan-Qiu
authors.initials: YQ
authors.lastname: Tan
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences CITY: Shanghai STATE: Shanghai China [CN].
authors.forename: Guo-Ning
authors.initials: GN
authors.lastname: Qi
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences CITY: Shanghai STATE: Shanghai China [CN].
authors.forename: Fen-Yong
authors.initials: FY
authors.lastname: Yao
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences CITY: Shanghai STATE: Shanghai China [CN].
authors.forename: Gui-Li
authors.initials: GL
authors.lastname: Wu
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences CITY: Shanghai STATE: Shanghai China [CN].
authors.forename: Lu-Wen
authors.initials: LW
authors.lastname: Yang
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences CITY: Shanghai STATE: Shanghai China [CN].
authors.forename: Jamshaid
authors.initials: J
authors.lastname: Hussain
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences CITY: Shanghai STATE: Shanghai China [CN].
authors.forename: Shu-Jing
authors.initials: SJ
authors.lastname: Sun
authors.affiliation: Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences CITY: Shanghai STATE: Shanghai POSTAL_CODE: 200032 China [CN] wangyongfei@sibs.ac.cn.
authors.forename: Yong-Fei
authors.initials: YF
authors.lastname: Wang