已知许多蛋白激酶及蛋白磷酸酶参与了ABA诱导的气孔关闭信号转导过程,而H_2O_2是ABA信号转导链的下游信号成分。运用表皮条生物学分析和激光共聚焦扫描技术,研究促细胞分裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)对蚕...已知许多蛋白激酶及蛋白磷酸酶参与了ABA诱导的气孔关闭信号转导过程,而H_2O_2是ABA信号转导链的下游信号成分。运用表皮条生物学分析和激光共聚焦扫描技术,研究促细胞分裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)对蚕豆保卫细胞中ABA诱导H_2O_2产生的调节作用。用MEK1/2专一抑制剂(PD98059)处理蚕豆叶片的下表皮,抑制了ABA诱导保卫细胞内H_2O_2的产生和气孔关闭。ABA和H_2O_2诱导气孔关闭后,再用PD98059处理,可以使关闭的气孔重新开放,与之相对应的是PD98059使ABA诱导的、已增强了的H_2O_2探针荧光强度降低。而且PD98059不能阻断水杨酸诱导的H_2O_2的产生及其气孔的关闭,因此,MEH1/2调节ABA诱导保卫细胞中H_2O_2产生和积累具有专一性。总之,PD98059通过抑制ABA诱导的H_2O_2的产生并清除其积累而阻断了ABA诱导的气孔关闭。因此,MAPK的激活在保卫细胞H_2O_2信号的产生、放大及其专一性应答信号刺激的反应中有着重要的调节作用。展开更多
It is known that cytoskeleton-dependent trafficking of cell wall and membrane components to apical plasma membrane （PM） coupled with ion transport across pollen PM is crucial for maintaining polar pollen tube growth...It is known that cytoskeleton-dependent trafficking of cell wall and membrane components to apical plasma membrane （PM） coupled with ion transport across pollen PM is crucial for maintaining polar pollen tube growth. To elucidate whether plant hormones are involved in these processes, the effects of exogenous phytohormones, indole-3-acetic acid （IAA）, abscisic acid （ABA）, gibberellin A3 （GA3） and cytokinin （kinetin） on the growth, PM polarization, actin cytoskeleton （AC） organization and cytoplasmic pH （pile） of in vitro 4 h-growing petunia pollen tubes were investigated. IAA, ABA and GA3 displayed the growth-stimulating effects and these were accompanied by orthovanadate-sensitive hyperpolarization of the PM. Fluorescent labeling the enzyme with H＋-ATPase antibodies exhibited IAA- and ABA-induced lateral PM redistribution of it into the subapical zone of pollen tube PM. Pollen cultivation on the medium with latrunculin B, the inhibitor of actin polymerization, resulted in inhibition of pollen tube growth and simultaneously in the drop of endogenous IAA content. The IAA-growth stimulating effect was correlated with increased content of actin filaments （AF） in both apical and subapical zones of tubes, while ABA and GA3 exerted the same effect but it was accompanied by redistributing F-actin only to apical zone. In contrast, kinetin decreased the total F-actin content and inhibited pollen tube growth. It has been shown that the pHe of growing pollen tubes is sensitive to the plant hormones. In the case of male gametophyte growing for 1, 2 and 4 h, IAA induced alkalinization of the cytosol, while ABA and GA3 exerted qualitatively similar effect only after its growth for 1 h and 4 h, respectively. Kinetin, in contrast, resulted in acidification of the cytosol. All these results, taken together, indicate, for the first time, potential targets of the phytohormone action in pollen tubes.展开更多
Plants gradually develop their ability to tolerate environmental water deficit as part of the evolutionary process.Abscisic acid(ABA) plays a critical role during drought and osmotic stress.Several histidine protein k...Plants gradually develop their ability to tolerate environmental water deficit as part of the evolutionary process.Abscisic acid(ABA) plays a critical role during drought and osmotic stress.Several histidine protein kinases are regarded as osmotic sensors or regulators in the adaptive response of plants to water deficit.In this study,we report that ATHK1,which was previously shown to function as an osmotic regulator,is involved in ABA-induced stomatal signaling in Arabidopsis.Mutants null for ATHK1 expression were unable to transmit normal ABA responses in guard cells,including inducing stomatal closure,producing hydrogen peroxide and activating calcium influx.Moreover,patch clamp and confocal analysis demonstrated that ATHK1 may function downstream of hydrogen peroxide in ABA-induced stomatal closure,by regulating calcium channel activity and calcium oscillation in Arabidopsis guard cells.展开更多
Our previous study demonstrated that a chloroplast co-chaperonin 20(CPN20),one of the interaction partners of the magnesium-protoporphyrin IX chelatase H subunit(CHLH/ABAR),negatively regulates ABA signaling at the sa...Our previous study demonstrated that a chloroplast co-chaperonin 20(CPN20),one of the interaction partners of the magnesium-protoporphyrin IX chelatase H subunit(CHLH/ABAR),negatively regulates ABA signaling at the same node with ABAR but upstream of WRKY40 transcription repressor in Arabidopsis thaliana.In the present experiment,we showed that ABA directly inhibits the ABAR-CPN20 interaction,and also represses expression of CPN20,which depends on ABAR.CPN20 inhibits ABAR-WRKY40 interaction by competitively binding to ABAR.ABAR downregulates,but CPN20 upregulates,WRKY40 expression.The cpn20-1 mutation induces downregulation of WRKY40,and suppresses the upregulated level of WRKY40 due to the cch mutation in the ABAR gene.ABA-induced repressive effect of the WRKY40 gene is strengthened by downregulation of CPN20 but reduced by upregulation of CPN20.Together with our previously reported genetic data,we provide evidence that CPN20 functions through antagonizing the ABAR-WRKY40 coupled pathway,and ABA relieves this pathway of repression by inhibiting the ABAR-CPN20 interaction to activate ABAR-WRKY40 interaction.展开更多
Hydrogen sulfide （H2S） is a newly discovered gaseous signaling molecule and involved in ethylene and ABA-induced stomatal closure. As an important factor, extracellular ATP （eATP） was believed to participate in re...Hydrogen sulfide （H2S） is a newly discovered gaseous signaling molecule and involved in ethylene and ABA-induced stomatal closure. As an important factor, extracellular ATP （eATP） was believed to participate in regulation of stomatal closing. However, the mechanism by which eATP mediates HES-regulated stomatal closure remains unclear. Here, we employed Arabidopsis wild-type and mutant lines of ATP-binding cassette transporters （Atmrp4, Atmrp5 and their double mutant Atmrp4/5） to study the function of eATP in H_2S-regulated stomatal movement. Our results indicated that H_2S affected stomatal closing through stimulating guard cell outward K^＋ current. Moreover, we found that HES induced eATP generation by regulating the activity of an ABC transporter. The inhibitor of ABC transporters, glibenclamide （Gli）, could impair H_2S-regulated stomatal closure and reduce H_2S-dependent eATP accumulation in Atmrp4 and Atmrp5 mutants. In addition, the promotion effect of H_2S on outward K^＋ currents was diminished in Atmrp4/5 double mutant. Our data suggested that hydrogen peroxide （H_2O_2） is required for H_2S-induced stomatal closure, and the production of H_2O_2 is regulated by eATP via NADPH oxidase. Based on this work, we conclude that H_2S-induced stomatal closure requires ABC transporter-dependent eATP pro- duction and subsequent NADPH oxidase-dependent H_2O_2 accumulation.展开更多
文摘已知许多蛋白激酶及蛋白磷酸酶参与了ABA诱导的气孔关闭信号转导过程,而H_2O_2是ABA信号转导链的下游信号成分。运用表皮条生物学分析和激光共聚焦扫描技术,研究促细胞分裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)对蚕豆保卫细胞中ABA诱导H_2O_2产生的调节作用。用MEK1/2专一抑制剂(PD98059)处理蚕豆叶片的下表皮,抑制了ABA诱导保卫细胞内H_2O_2的产生和气孔关闭。ABA和H_2O_2诱导气孔关闭后,再用PD98059处理,可以使关闭的气孔重新开放,与之相对应的是PD98059使ABA诱导的、已增强了的H_2O_2探针荧光强度降低。而且PD98059不能阻断水杨酸诱导的H_2O_2的产生及其气孔的关闭,因此,MEH1/2调节ABA诱导保卫细胞中H_2O_2产生和积累具有专一性。总之,PD98059通过抑制ABA诱导的H_2O_2的产生并清除其积累而阻断了ABA诱导的气孔关闭。因此,MAPK的激活在保卫细胞H_2O_2信号的产生、放大及其专一性应答信号刺激的反应中有着重要的调节作用。
文摘It is known that cytoskeleton-dependent trafficking of cell wall and membrane components to apical plasma membrane （PM） coupled with ion transport across pollen PM is crucial for maintaining polar pollen tube growth. To elucidate whether plant hormones are involved in these processes, the effects of exogenous phytohormones, indole-3-acetic acid （IAA）, abscisic acid （ABA）, gibberellin A3 （GA3） and cytokinin （kinetin） on the growth, PM polarization, actin cytoskeleton （AC） organization and cytoplasmic pH （pile） of in vitro 4 h-growing petunia pollen tubes were investigated. IAA, ABA and GA3 displayed the growth-stimulating effects and these were accompanied by orthovanadate-sensitive hyperpolarization of the PM. Fluorescent labeling the enzyme with H＋-ATPase antibodies exhibited IAA- and ABA-induced lateral PM redistribution of it into the subapical zone of pollen tube PM. Pollen cultivation on the medium with latrunculin B, the inhibitor of actin polymerization, resulted in inhibition of pollen tube growth and simultaneously in the drop of endogenous IAA content. The IAA-growth stimulating effect was correlated with increased content of actin filaments （AF） in both apical and subapical zones of tubes, while ABA and GA3 exerted the same effect but it was accompanied by redistributing F-actin only to apical zone. In contrast, kinetin decreased the total F-actin content and inhibited pollen tube growth. It has been shown that the pHe of growing pollen tubes is sensitive to the plant hormones. In the case of male gametophyte growing for 1, 2 and 4 h, IAA induced alkalinization of the cytosol, while ABA and GA3 exerted qualitatively similar effect only after its growth for 1 h and 4 h, respectively. Kinetin, in contrast, resulted in acidification of the cytosol. All these results, taken together, indicate, for the first time, potential targets of the phytohormone action in pollen tubes.
基金supported by the National Basic Research Program of China (2012CB114301)the National Natural Science Foundation of China (31070238 and 31170252)
文摘Plants gradually develop their ability to tolerate environmental water deficit as part of the evolutionary process.Abscisic acid(ABA) plays a critical role during drought and osmotic stress.Several histidine protein kinases are regarded as osmotic sensors or regulators in the adaptive response of plants to water deficit.In this study,we report that ATHK1,which was previously shown to function as an osmotic regulator,is involved in ABA-induced stomatal signaling in Arabidopsis.Mutants null for ATHK1 expression were unable to transmit normal ABA responses in guard cells,including inducing stomatal closure,producing hydrogen peroxide and activating calcium influx.Moreover,patch clamp and confocal analysis demonstrated that ATHK1 may function downstream of hydrogen peroxide in ABA-induced stomatal closure,by regulating calcium channel activity and calcium oscillation in Arabidopsis guard cells.
基金supported by the National Key Basic Research Program of China(2012CB114302)National Natural Science Foundation of China(90817104 and 31170268)Ministry of Agriculture of China(2013ZX08009-003)
文摘Our previous study demonstrated that a chloroplast co-chaperonin 20(CPN20),one of the interaction partners of the magnesium-protoporphyrin IX chelatase H subunit(CHLH/ABAR),negatively regulates ABA signaling at the same node with ABAR but upstream of WRKY40 transcription repressor in Arabidopsis thaliana.In the present experiment,we showed that ABA directly inhibits the ABAR-CPN20 interaction,and also represses expression of CPN20,which depends on ABAR.CPN20 inhibits ABAR-WRKY40 interaction by competitively binding to ABAR.ABAR downregulates,but CPN20 upregulates,WRKY40 expression.The cpn20-1 mutation induces downregulation of WRKY40,and suppresses the upregulated level of WRKY40 due to the cch mutation in the ABAR gene.ABA-induced repressive effect of the WRKY40 gene is strengthened by downregulation of CPN20 but reduced by upregulation of CPN20.Together with our previously reported genetic data,we provide evidence that CPN20 functions through antagonizing the ABAR-WRKY40 coupled pathway,and ABA relieves this pathway of repression by inhibiting the ABAR-CPN20 interaction to activate ABAR-WRKY40 interaction.
基金supported by the National Natural Science Foundation of China(31170237)the National Key Laboratory Program of China Agricultural University(SKLPPBKF11001)Shandong Taishan Scholar Program
文摘Hydrogen sulfide （H2S） is a newly discovered gaseous signaling molecule and involved in ethylene and ABA-induced stomatal closure. As an important factor, extracellular ATP （eATP） was believed to participate in regulation of stomatal closing. However, the mechanism by which eATP mediates HES-regulated stomatal closure remains unclear. Here, we employed Arabidopsis wild-type and mutant lines of ATP-binding cassette transporters （Atmrp4, Atmrp5 and their double mutant Atmrp4/5） to study the function of eATP in H_2S-regulated stomatal movement. Our results indicated that H_2S affected stomatal closing through stimulating guard cell outward K^＋ current. Moreover, we found that HES induced eATP generation by regulating the activity of an ABC transporter. The inhibitor of ABC transporters, glibenclamide （Gli）, could impair H_2S-regulated stomatal closure and reduce H_2S-dependent eATP accumulation in Atmrp4 and Atmrp5 mutants. In addition, the promotion effect of H_2S on outward K^＋ currents was diminished in Atmrp4/5 double mutant. Our data suggested that hydrogen peroxide （H_2O_2） is required for H_2S-induced stomatal closure, and the production of H_2O_2 is regulated by eATP via NADPH oxidase. Based on this work, we conclude that H_2S-induced stomatal closure requires ABC transporter-dependent eATP pro- duction and subsequent NADPH oxidase-dependent H_2O_2 accumulation.
