Pharmacological, laser scanning confocal microscopic （LSCM）, and spectrophotographic approaches were used to study the roles of hydrogen sulfide （H2S） and nitric oxide （NO） in signaling transduction of stomatal ...Pharmacological, laser scanning confocal microscopic （LSCM）, and spectrophotographic approaches were used to study the roles of hydrogen sulfide （H2S） and nitric oxide （NO） in signaling transduction of stomatal movement in response to ethylene in Viciafaba L. Ethylene treatment resulted in the dose-dependent stomatal closure under light, and this effect was blocked by the inhibitors of H2S biosynthesis in V. faba L. Additionally, ethylene induces H2S generation and increases L-/D-cysteine desulfhydrase （pyridoxalphosphate-dependent enzyme） activity in leaves of V. faba L. Inhibitors of H2S biosynthesis have no effect on the ethylene-induced stomatal closure, NO accumulation, and nitrate reductase （NR） activity in guard cells or leaves of II. faba L. Moreover, the ethylene-induced increase of H2S levels and L-/D- cysteine desulfhydrase activity declined when NO generation was inhibited. Therefore, we conclude that H2S and NO probably are involved in the signal transduction pathway of ethylene-induced stomatal closure. H2S may represent a novel component downstream of NO in the ethylene-induced stomatal movement in V. faba L.展开更多
Hydrogen sulfide （H2S） is a newly-discovered signaling molecule in plants and has caused increasing attention in recent years, but its function in stomatal movement is unclear. In plants, H2S is synthesized via cyst...Hydrogen sulfide （H2S） is a newly-discovered signaling molecule in plants and has caused increasing attention in recent years, but its function in stomatal movement is unclear. In plants, H2S is synthesized via cysteine degradation catalyzed by D-/L-cysteine desulfhydrase （D-/L-CDes）. AtD-/L-CDes：：GUS transgenic Arabidopsis thaliana （L.） Heynh. plants were generated and used to investigate gene expression patterns, and results showed that AtD-/L-CDes can be expressed in guard cells. We also determined the subcellular localization of AtD-/L-CDes using transgenic plants of AtD-/L-CDes：：GFP, and the results showed that AtD-CDes and AtL-CDes are located in the chloroplast and in the cytoplasm, respectively. The transcript levels of AtD-CDes and AtL-CDes were affected by the chemicals that cause stomatal closure. Among these factors, ACC, a precursor of ethylene, has the most significant effect, which indicates that the H2S generated from D-/L-CDes may play an important role in ethylene-induced stomatal closure. Meanwhile, H2S synthetic inhibitors significantly inhibited ethylene-induced stomatal closure in Arabidopsis. Ethylene treatment caused an increase of H2S production and of AtD-/L-CDes activity in Arabidopsis leaves. AtD-/L-CDes over-expressing plants exhibited enhanced induction of stomatal closure compared to the wild-type after ethylene treatment; however, the effect was not observed in the Atd-cdes and Atl-cdes mutants. In conclusion, our results suggest that the D-/L-CDes-generated H2S is involved in the regulation of ethylene-induced stomatal closure in Arabidopsis thaliana.展开更多
Plant stomata close rapidly in response to a rise in the plant hormone abscisic acid(ABA)or salicylic acid(SA)and after recognition of pathogenassociated molecular patterns(PAMPs).Stomatal closure is the result of vac...Plant stomata close rapidly in response to a rise in the plant hormone abscisic acid(ABA)or salicylic acid(SA)and after recognition of pathogenassociated molecular patterns(PAMPs).Stomatal closure is the result of vacuolar convolution,ion efflux,and changes in turgor pressure in guard cells.Phytopathogenic bacteria secrete typeⅢeffectors(T3Es)that interfere with plant defense mechanisms,causing severe plant disease symptoms.Here,we show that the virulence and infection of Xanthomonas oryzae pv.oryzicola(Xoc),which is the causal agent of rice bacterial leaf streak disease,drastically increased in transgenic rice(Oryza sativa L.)plants overexpressing the Xoc T3E gene Xop AP,which encodes a protein annotated as a lipase.We discovered that Xop AP binds to phosphatidylinositol 3,5-bisphosphate(Ptd Ins(3,5)P_(2)),a memb rane phospholipid that functions in p H control in lysosomes,membrane dynamics,and protein trafficking.Xop AP inhibited the acidification of vacuoles by competing with vacuolar H^(+)-pyrophosphatase(V-PPase)for binding to Ptd Ins(3,5)P_(2),leading to stomatal opening.Transgenic rice overexpressing Xop AP also showed inhibition of stomatal closure when challenged by Xoc infection and treatment with the PAMP flg22.Moreover,Xop AP suppressed flg22-induced gene expression,reactive oxygen species burst and callose deposition in host plants,demonstrating that Xop AP subverts PAMP-triggered immunity during Xoc infection.Taken together,these findings demonstrate that Xop AP overcomes stomatal immunity in plants by binding to lipids.展开更多
Water stress is one of the major environmental stresses that affect agricultural production worldwide. Water loss from plants occurs primarily through stomatal pores. Here, we report that an Oryza sativa half-size ATP...Water stress is one of the major environmental stresses that affect agricultural production worldwide. Water loss from plants occurs primarily through stomatal pores. Here, we report that an Oryza sativa half-size ATP-binding cassette （ABC） subfamily G protein, RCN 1/OsABCG5, is involved in stomatal closure mediated by phytohormone abscisic acid （ABA） accumulation in guard cells. We found that the GFP-RCN1/ OsABCG5-fusion protein was localized at the plasma membrane in guard cells. The percentage of guard cell pairs containing both ABA and GFP-RCN1/OsABCG5 increased after exogenous ABA treatment, whereas they were co-localized in guard cell pairs regardless of whether exogenous ABA was applied. ABA application resulted in a smaller increase in the percentage of guard cell pairs containing ABA in rcnl mutant （A684P） and RCN1-RNAi than in wild-type plants. Furthermore, polyethylene glycol （drought stress）-inducible ABA accumulation in guard cells did not occur in rcnl mutants. Stomata closure mediated by exogenous ABA application was strongly reduced in rcnl mutants. Finally, rcnl mutant plants had more rapid water loss from detached leaves than the wild-type plants. These results indicate that in response to drought stress, RCN1/OsABCG5 is involved in accumulation of ABA in guard cells, which is indispensable for stomatal closure.展开更多
The role and signaling of sphingosine-l-phosphate （SIP） during darkness-induced stomatal closure were examined in Vicia faba. Darkness substantially raised S 1P and hydrogen peroxide （H202） levels and closed stoma...The role and signaling of sphingosine-l-phosphate （SIP） during darkness-induced stomatal closure were examined in Vicia faba. Darkness substantially raised S 1P and hydrogen peroxide （H202） levels and closed stomata. These darkness effects were significantly suppressed by DL-threo-dihydrosphingosine （DL-threo-DHS） and N,N-dimethylsphingosine （DMS）, two inhibi- tors of long-chain base kinases. Exogenous SIP led to stomatal closure and H202 production, and the effects of SIP were largely prevented by the H202 modulators ascorbic acid, catalase, and diphenyleneiodonium. These results indicated that SIP mediated darkness-induced stomatal closure by triggering H202 production. In addition, DL-threo-DHS and DMS significantly suppressed both darkness-induced cytosolic alkalization in guard cells and stomatal closure. Exogenous SIP caused cytosolic alkalization and stomatal closure, which could be largely abolished by butyric acid. These results demonstrated that SIP syn-thesis was necessary for cytosolic alkalization during stomatal closure caused by darkness. Furthermore, together with the data described above, inhibition of darkness-induced H202 production by butyric acid revealed that S 1P synthesis-induced cytosolic alkalization was a prerequisite for H202 production during stomatal closure caused by darkness, a conclusion supported by the facts that the pH increase caused by exogenous SIP had a shorter lag and peaked faster than H202 levels and that butyric acid prevented exogenous SIP-induced H202 production. Altogether, our data suggested that darkness induced SIP synthesis, causing cytosolic alkalization and subsequent H202 production, finally leading to stomatal closure.展开更多
Mitogen-activated protein kinases(MPKs)play essential roles in guard cell signaling,but whether MPK cascades participate in guard cell ethylene signaling and interact with hydrogen peroxide(H2O2),nitric oxide(NO),and ...Mitogen-activated protein kinases(MPKs)play essential roles in guard cell signaling,but whether MPK cascades participate in guard cell ethylene signaling and interact with hydrogen peroxide(H2O2),nitric oxide(NO),and ethylene-signaling components remain unclear.Here,we report that ethylene activated MPK3 and MPK6 in the leaves of wild-type Arabidopsis thaliana as well as ethylene insensitive2(ein2),ein3,nitrate reductase1(nia1),and nia2 mutants,but this effect was impaired in ethylene response1(etr1),nicotinamide adenine dinucleotide phosphate oxidase AtrbohF,mpk kinase1(mkk1),and mkk3 mutants.By contrast,the constitutive triple response1(ctr1)mutant had constitutively active MPK3 and MPK6.Yeast two-hybrid,bimolecular fluorescence complementation,and pull-down assays indicated that MPK3 and MPK6 physically interacted with MKK1,MKK3,and the C-terminal region of EIN2(EIN2 CEND).mkk1,mkk3,mpk3,and mpk6 mutants had typical levels of ethylene-induced H2O2 generation but impaired ethylene-induced EIN2 CEND cleavage and nuclear translocation,EIN3 protein accumulation,NO production in guard cells,and stomatal closure.These results show that the MKK1/3–MPK3/6 cascade mediates ethylene-induced stomatal closure by functioning downstream of ETR1,CTR1,and H2O2 to interact with EIN2,thereby promoting EIN3 accumulation and EIN3-dependent NO production in guard cells.展开更多
Ongoing climate change has a considerable influence on the seasonality,timing,and intensity of rainfall worldwide,and is also predicted to decrease snow cover in cold ecosystems.Larch is a widely distributed tree spec...Ongoing climate change has a considerable influence on the seasonality,timing,and intensity of rainfall worldwide,and is also predicted to decrease snow cover in cold ecosystems.Larch is a widely distributed tree species in boreal Eurasia,calling for a comprehensive understanding of how larch adapts to changes in both rainfall and snowfall by adjusting carbon-water physiology.Here,we conducted a short-term rainfall(−60% ambient rainfall;three-year)and snowfall(−73% ambient snowfall;two-year)exclusions experiment in Larix gmelinii forest in northeastern China,and aimed to explore the responses of hydraulic(leaf pressure-volume traits,leaf and branch hydraulic conductivity and embolism resistance),stomatal(stomatal closure point and stomatal safety margin),and economic(photosynthetic rate,nutrient and non-structural carbohydrates contents)traits to rainfall and snowfall reductions.Despite the weak alternation of leaf and branch hydraulic traits,both rainfall and snowfall reductions significantly led to early stomatal closure and increased stomatal safety margins(the difference between stomatal closure point and xylem embolism threshold,describing drought resistance by merging both hydraulic and stomatal strategies).Reductions in rainfall and snowfall induced water or/and low-temperature stress,resulting in more conservative leaf economic traits,including a reduced photosynthetic rate,lower leaf nitrogen concentration,and higher leaf density.In addition,larch responded to reductions in rainfall and snowfall by up-regulating non-structural carbohydrates in the xylem,which helps repair embolism or lower the freezing point acting as osmolytes.Overall,our findings reveal that larch could adapt to the drought and snowpack reduction by strict stomatal regulation and investing non-structural carbohydrates in embolism repairing,at the cost of carbon assimilation.展开更多
This paper briefly reviews the physiological mechanisms for improving crop water use and water use efficiency in dryland farming regions of Loess Plateau on the basis of its environmental conditions and progress in cr...This paper briefly reviews the physiological mechanisms for improving crop water use and water use efficiency in dryland farming regions of Loess Plateau on the basis of its environmental conditions and progress in crop water relations and the biological basis of water saving agriculture, especially in non uniform stomatal closure, ABA effects, communication between root and shoot, and water use efficiency. Root chemical signals about water shortage are feedforward effect which contributes to balanced water relations within the plant compartment of the soil plant atmosphere continuum. ABA production is increased in tissues during these stresses, and this causes a variety of physiological effects, including stomata closure in leaves. It is concluded that the root chemical signal ABA is very important to improve the crop water use efficiency in semi arid area of Loess Plateau.展开更多
Global warming and climate change are accelerating,and drought has become a major threat to global agriculture,severely affecting crop yields and food security.To survive water scarcity,plants have developed various s...Global warming and climate change are accelerating,and drought has become a major threat to global agriculture,severely affecting crop yields and food security.To survive water scarcity,plants have developed various strategies.One important mechanism is stomatal closure(气孔关闭).Stomata,the tiny holes on leaf surfaces,regulate gas exchange and water loss.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
Ambient pH performs a crucial role in plant immunity,abiotic stress response,and plant growth and development.Plant-pathogen interactions influence a dynamic pH environment.Host acidification and alkalinization are un...Ambient pH performs a crucial role in plant immunity,abiotic stress response,and plant growth and development.Plant-pathogen interactions influence a dynamic pH environment.Host acidification and alkalinization are under the regulating actions of acidophilic and alkaliphilic pathogens,respectively.Plasma membrane H+-ATPases regulate pH homeostasis,and their activity is modulated during pathogen-associated molecular pattern-(PTI)and effector-triggered immunities(ETI).Recent studies have provided insights into the interplay between pathogens and plants when controlling ambient pH.Here,we review pH dynamics in relation to plant immunity and focus on its relationships with PTI,ETI,stomatal immunity,programmed cell death,calcium ion(Ca^(2+)),and reactive oxygen species.Comprehension of the complexity of ambient pH regulation may provide new strategies for plant disease control and sustainable agriculture.展开更多
The phytohormone abscisic acid(ABA)plays pivotal roles in triggering stomatal closure and facilitating adaptation of plants to drought stress.Hydrogen sulfide(H2S),a small signaling gas molecule,is involved in ABA-dep...The phytohormone abscisic acid(ABA)plays pivotal roles in triggering stomatal closure and facilitating adaptation of plants to drought stress.Hydrogen sulfide(H2S),a small signaling gas molecule,is involved in ABA-dependent stomatal closure.However,how H2S regulates ABA signaling remains largely unclear.Here,we show that ABA induces the production of H2S catalyzed by L-CYSTEINE DESULFHYDRASE1(DES1)in guard cells,and H2S in turn positively regulates ABA signaling through persulfidation of Open Stomata 1(OST1)/SNF1-RELATED PROTEIN KINASE2.6(SnRK2.6).Two cysteine(Cys)sites,Cys131 and Cys137,which are exposed on the surface of SnRK2.6 and close to the activation loop,were identified to be persulfidated,which promotes the activity of SnRK2.6 and its interaction with ABA response element-binding factor 2(ABF2),a transcription factor acting downstream of ABA signaling.When Cys131,Cys137,or both residues in SnRK2.6 were substituted with serine(S),H2S_induced SnRK2_6 activity and SnRK2.6-ABF2 interaction were partially(SnRK2.6c131s and SnRK2.6c137S)or completely(SnRK2.6c131sc137S)compromised.Introduction of SnRK2.6c131s,SnRK2.6c137S,or SnRK2.6c131sc137S into the ost1-3 mutant could not rescue the mutant phenotype:less sensitivity to ABA-and H2S-induced stomatal closure and Ca2+influx as well as increased water loss and decreased drought tolerance.Taken together,our study reveals a novel post-translational regulatory mechanism of ABA signaling whereby H2S persulfidates SnRK2.6 to promote ABA signaling and ABA-induced stomatal closure.展开更多
Stomatal movements are critical in regulating gas exchange for photosynthesis and water balance between plant tissues and the atmosphere. The plant hormone abscisic acid （ABA） plays key roles in regulating stomatal ...Stomatal movements are critical in regulating gas exchange for photosynthesis and water balance between plant tissues and the atmosphere. The plant hormone abscisic acid （ABA） plays key roles in regulating stomatal closure under various abiotic stresses. In this study, we revealed a novel role of BAKI in guard cell ABA signaling. We found that the brassinosteroid （BR） signaling mutant bakl lost more water than wild- type plants and showed ABA insensitivity in stomatal closure. ABA-induced OST1 expression and reactive oxygen species （ROS） production were also impaired in bakl. Unlike direct treatment with H202, overex-pression of OST1 did not completely rescue the insensitivity of bakl to ABA. We demonstrated that BAK1 forms a complex with OST1 near the plasma membrane and that the BAKI/OST1 complex is increased in response to ABA in planta. Brassinolide, the most active BR, exerted a negative effect on ABA-induced formation of the BAK1/OST1 complex and OST1 expression. Moreover, we found that BAK1 and ABI1 oppositely regulate OST1 phosphorylation in vitro, and that ABI1 interacts with BAK1 and inhibits the interaction of BAK1 and OST1. Taken together, our results suggest that BAK1 regulates ABA-induced stomatal closure in guard cells.展开更多
基金supported by the National Natural Science Foundation of China (30970288 and 31170237)the National Science Foundation of Shandong Province, China(ZR2010CM024)the Foundation of State Key Laboratory of Plant Physiology and Biochemistry, China(SKLPPBKF11001)
文摘Pharmacological, laser scanning confocal microscopic （LSCM）, and spectrophotographic approaches were used to study the roles of hydrogen sulfide （H2S） and nitric oxide （NO） in signaling transduction of stomatal movement in response to ethylene in Viciafaba L. Ethylene treatment resulted in the dose-dependent stomatal closure under light, and this effect was blocked by the inhibitors of H2S biosynthesis in V. faba L. Additionally, ethylene induces H2S generation and increases L-/D-cysteine desulfhydrase （pyridoxalphosphate-dependent enzyme） activity in leaves of V. faba L. Inhibitors of H2S biosynthesis have no effect on the ethylene-induced stomatal closure, NO accumulation, and nitrate reductase （NR） activity in guard cells or leaves of II. faba L. Moreover, the ethylene-induced increase of H2S levels and L-/D- cysteine desulfhydrase activity declined when NO generation was inhibited. Therefore, we conclude that H2S and NO probably are involved in the signal transduction pathway of ethylene-induced stomatal closure. H2S may represent a novel component downstream of NO in the ethylene-induced stomatal movement in V. faba L.
基金supported by the National Natural Science Foundation of China (30970228 and 31170237)the National Natural Science Foundation of Shandong Province of China (ZR2010CM024)the Foundation of The State Key Laboratory of Plant Physiology and Biochemistry(SKLPPBKF11001)
文摘Hydrogen sulfide （H2S） is a newly-discovered signaling molecule in plants and has caused increasing attention in recent years, but its function in stomatal movement is unclear. In plants, H2S is synthesized via cysteine degradation catalyzed by D-/L-cysteine desulfhydrase （D-/L-CDes）. AtD-/L-CDes：：GUS transgenic Arabidopsis thaliana （L.） Heynh. plants were generated and used to investigate gene expression patterns, and results showed that AtD-/L-CDes can be expressed in guard cells. We also determined the subcellular localization of AtD-/L-CDes using transgenic plants of AtD-/L-CDes：：GFP, and the results showed that AtD-CDes and AtL-CDes are located in the chloroplast and in the cytoplasm, respectively. The transcript levels of AtD-CDes and AtL-CDes were affected by the chemicals that cause stomatal closure. Among these factors, ACC, a precursor of ethylene, has the most significant effect, which indicates that the H2S generated from D-/L-CDes may play an important role in ethylene-induced stomatal closure. Meanwhile, H2S synthetic inhibitors significantly inhibited ethylene-induced stomatal closure in Arabidopsis. Ethylene treatment caused an increase of H2S production and of AtD-/L-CDes activity in Arabidopsis leaves. AtD-/L-CDes over-expressing plants exhibited enhanced induction of stomatal closure compared to the wild-type after ethylene treatment; however, the effect was not observed in the Atd-cdes and Atl-cdes mutants. In conclusion, our results suggest that the D-/L-CDes-generated H2S is involved in the regulation of ethylene-induced stomatal closure in Arabidopsis thaliana.
基金supported by the Shanghai Agriculture Applied Technology Development Program,China(2020-02-08-00-08-F01462)the National Natural Science Foundation of China(31830072,32102147)。
文摘Plant stomata close rapidly in response to a rise in the plant hormone abscisic acid(ABA)or salicylic acid(SA)and after recognition of pathogenassociated molecular patterns(PAMPs).Stomatal closure is the result of vacuolar convolution,ion efflux,and changes in turgor pressure in guard cells.Phytopathogenic bacteria secrete typeⅢeffectors(T3Es)that interfere with plant defense mechanisms,causing severe plant disease symptoms.Here,we show that the virulence and infection of Xanthomonas oryzae pv.oryzicola(Xoc),which is the causal agent of rice bacterial leaf streak disease,drastically increased in transgenic rice(Oryza sativa L.)plants overexpressing the Xoc T3E gene Xop AP,which encodes a protein annotated as a lipase.We discovered that Xop AP binds to phosphatidylinositol 3,5-bisphosphate(Ptd Ins(3,5)P_(2)),a memb rane phospholipid that functions in p H control in lysosomes,membrane dynamics,and protein trafficking.Xop AP inhibited the acidification of vacuoles by competing with vacuolar H^(+)-pyrophosphatase(V-PPase)for binding to Ptd Ins(3,5)P_(2),leading to stomatal opening.Transgenic rice overexpressing Xop AP also showed inhibition of stomatal closure when challenged by Xoc infection and treatment with the PAMP flg22.Moreover,Xop AP suppressed flg22-induced gene expression,reactive oxygen species burst and callose deposition in host plants,demonstrating that Xop AP subverts PAMP-triggered immunity during Xoc infection.Taken together,these findings demonstrate that Xop AP overcomes stomatal immunity in plants by binding to lipids.
文摘Water stress is one of the major environmental stresses that affect agricultural production worldwide. Water loss from plants occurs primarily through stomatal pores. Here, we report that an Oryza sativa half-size ATP-binding cassette （ABC） subfamily G protein, RCN 1/OsABCG5, is involved in stomatal closure mediated by phytohormone abscisic acid （ABA） accumulation in guard cells. We found that the GFP-RCN1/ OsABCG5-fusion protein was localized at the plasma membrane in guard cells. The percentage of guard cell pairs containing both ABA and GFP-RCN1/OsABCG5 increased after exogenous ABA treatment, whereas they were co-localized in guard cell pairs regardless of whether exogenous ABA was applied. ABA application resulted in a smaller increase in the percentage of guard cell pairs containing ABA in rcnl mutant （A684P） and RCN1-RNAi than in wild-type plants. Furthermore, polyethylene glycol （drought stress）-inducible ABA accumulation in guard cells did not occur in rcnl mutants. Stomata closure mediated by exogenous ABA application was strongly reduced in rcnl mutants. Finally, rcnl mutant plants had more rapid water loss from detached leaves than the wild-type plants. These results indicate that in response to drought stress, RCN1/OsABCG5 is involved in accumulation of ABA in guard cells, which is indispensable for stomatal closure.
基金supported by the Graduate Education Innovation Program Projects of Ministry of Education, China (Grant No. F-0922)
文摘The role and signaling of sphingosine-l-phosphate （SIP） during darkness-induced stomatal closure were examined in Vicia faba. Darkness substantially raised S 1P and hydrogen peroxide （H202） levels and closed stomata. These darkness effects were significantly suppressed by DL-threo-dihydrosphingosine （DL-threo-DHS） and N,N-dimethylsphingosine （DMS）, two inhibi- tors of long-chain base kinases. Exogenous SIP led to stomatal closure and H202 production, and the effects of SIP were largely prevented by the H202 modulators ascorbic acid, catalase, and diphenyleneiodonium. These results indicated that SIP mediated darkness-induced stomatal closure by triggering H202 production. In addition, DL-threo-DHS and DMS significantly suppressed both darkness-induced cytosolic alkalization in guard cells and stomatal closure. Exogenous SIP caused cytosolic alkalization and stomatal closure, which could be largely abolished by butyric acid. These results demonstrated that SIP syn-thesis was necessary for cytosolic alkalization during stomatal closure caused by darkness. Furthermore, together with the data described above, inhibition of darkness-induced H202 production by butyric acid revealed that S 1P synthesis-induced cytosolic alkalization was a prerequisite for H202 production during stomatal closure caused by darkness, a conclusion supported by the facts that the pH increase caused by exogenous SIP had a shorter lag and peaked faster than H202 levels and that butyric acid prevented exogenous SIP-induced H202 production. Altogether, our data suggested that darkness induced SIP synthesis, causing cytosolic alkalization and subsequent H202 production, finally leading to stomatal closure.
基金supported by the National Natural Science Foundation of China(31570397,31870375)the Natural Science Research Plan of Shaanxi Province of China(2016JZ008)the Excellent Doctoral Dissertation Project of Shaanxi Normal University(2017TS037).
文摘Mitogen-activated protein kinases(MPKs)play essential roles in guard cell signaling,but whether MPK cascades participate in guard cell ethylene signaling and interact with hydrogen peroxide(H2O2),nitric oxide(NO),and ethylene-signaling components remain unclear.Here,we report that ethylene activated MPK3 and MPK6 in the leaves of wild-type Arabidopsis thaliana as well as ethylene insensitive2(ein2),ein3,nitrate reductase1(nia1),and nia2 mutants,but this effect was impaired in ethylene response1(etr1),nicotinamide adenine dinucleotide phosphate oxidase AtrbohF,mpk kinase1(mkk1),and mkk3 mutants.By contrast,the constitutive triple response1(ctr1)mutant had constitutively active MPK3 and MPK6.Yeast two-hybrid,bimolecular fluorescence complementation,and pull-down assays indicated that MPK3 and MPK6 physically interacted with MKK1,MKK3,and the C-terminal region of EIN2(EIN2 CEND).mkk1,mkk3,mpk3,and mpk6 mutants had typical levels of ethylene-induced H2O2 generation but impaired ethylene-induced EIN2 CEND cleavage and nuclear translocation,EIN3 protein accumulation,NO production in guard cells,and stomatal closure.These results show that the MKK1/3–MPK3/6 cascade mediates ethylene-induced stomatal closure by functioning downstream of ETR1,CTR1,and H2O2 to interact with EIN2,thereby promoting EIN3 accumulation and EIN3-dependent NO production in guard cells.
基金supported by the National Key R&D Program of China(2022YFE0127900,2021YFD2200401)the National Natural Science Foundation of China(31901278).
文摘Ongoing climate change has a considerable influence on the seasonality,timing,and intensity of rainfall worldwide,and is also predicted to decrease snow cover in cold ecosystems.Larch is a widely distributed tree species in boreal Eurasia,calling for a comprehensive understanding of how larch adapts to changes in both rainfall and snowfall by adjusting carbon-water physiology.Here,we conducted a short-term rainfall(−60% ambient rainfall;three-year)and snowfall(−73% ambient snowfall;two-year)exclusions experiment in Larix gmelinii forest in northeastern China,and aimed to explore the responses of hydraulic(leaf pressure-volume traits,leaf and branch hydraulic conductivity and embolism resistance),stomatal(stomatal closure point and stomatal safety margin),and economic(photosynthetic rate,nutrient and non-structural carbohydrates contents)traits to rainfall and snowfall reductions.Despite the weak alternation of leaf and branch hydraulic traits,both rainfall and snowfall reductions significantly led to early stomatal closure and increased stomatal safety margins(the difference between stomatal closure point and xylem embolism threshold,describing drought resistance by merging both hydraulic and stomatal strategies).Reductions in rainfall and snowfall induced water or/and low-temperature stress,resulting in more conservative leaf economic traits,including a reduced photosynthetic rate,lower leaf nitrogen concentration,and higher leaf density.In addition,larch responded to reductions in rainfall and snowfall by up-regulating non-structural carbohydrates in the xylem,which helps repair embolism or lower the freezing point acting as osmolytes.Overall,our findings reveal that larch could adapt to the drought and snowpack reduction by strict stomatal regulation and investing non-structural carbohydrates in embolism repairing,at the cost of carbon assimilation.
文摘This paper briefly reviews the physiological mechanisms for improving crop water use and water use efficiency in dryland farming regions of Loess Plateau on the basis of its environmental conditions and progress in crop water relations and the biological basis of water saving agriculture, especially in non uniform stomatal closure, ABA effects, communication between root and shoot, and water use efficiency. Root chemical signals about water shortage are feedforward effect which contributes to balanced water relations within the plant compartment of the soil plant atmosphere continuum. ABA production is increased in tissues during these stresses, and this causes a variety of physiological effects, including stomata closure in leaves. It is concluded that the root chemical signal ABA is very important to improve the crop water use efficiency in semi arid area of Loess Plateau.
文摘Global warming and climate change are accelerating,and drought has become a major threat to global agriculture,severely affecting crop yields and food security.To survive water scarcity,plants have developed various strategies.One important mechanism is stomatal closure(气孔关闭).Stomata,the tiny holes on leaf surfaces,regulate gas exchange and water loss.
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.
基金supported by the National Natural Science Foundation of China(Grant no.32072534 and 32272693)the Natural Science Basic Research Program of Shaanxi(Grant no.2024JC-YBQN-0186 and 2022JQ-161).
文摘Ambient pH performs a crucial role in plant immunity,abiotic stress response,and plant growth and development.Plant-pathogen interactions influence a dynamic pH environment.Host acidification and alkalinization are under the regulating actions of acidophilic and alkaliphilic pathogens,respectively.Plasma membrane H+-ATPases regulate pH homeostasis,and their activity is modulated during pathogen-associated molecular pattern-(PTI)and effector-triggered immunities(ETI).Recent studies have provided insights into the interplay between pathogens and plants when controlling ambient pH.Here,we review pH dynamics in relation to plant immunity and focus on its relationships with PTI,ETI,stomatal immunity,programmed cell death,calcium ion(Ca^(2+)),and reactive oxygen species.Comprehension of the complexity of ambient pH regulation may provide new strategies for plant disease control and sustainable agriculture.
基金the National Natural Science Foundation of China(NSFC 31700445,31400246)Shaanxi Province Natural Science Foundation of China(2018JM3017,2018JQ3020)China Postdoctoral Science Foundation(2018M641022).
文摘The phytohormone abscisic acid(ABA)plays pivotal roles in triggering stomatal closure and facilitating adaptation of plants to drought stress.Hydrogen sulfide(H2S),a small signaling gas molecule,is involved in ABA-dependent stomatal closure.However,how H2S regulates ABA signaling remains largely unclear.Here,we show that ABA induces the production of H2S catalyzed by L-CYSTEINE DESULFHYDRASE1(DES1)in guard cells,and H2S in turn positively regulates ABA signaling through persulfidation of Open Stomata 1(OST1)/SNF1-RELATED PROTEIN KINASE2.6(SnRK2.6).Two cysteine(Cys)sites,Cys131 and Cys137,which are exposed on the surface of SnRK2.6 and close to the activation loop,were identified to be persulfidated,which promotes the activity of SnRK2.6 and its interaction with ABA response element-binding factor 2(ABF2),a transcription factor acting downstream of ABA signaling.When Cys131,Cys137,or both residues in SnRK2.6 were substituted with serine(S),H2S_induced SnRK2_6 activity and SnRK2.6-ABF2 interaction were partially(SnRK2.6c131s and SnRK2.6c137S)or completely(SnRK2.6c131sc137S)compromised.Introduction of SnRK2.6c131s,SnRK2.6c137S,or SnRK2.6c131sc137S into the ost1-3 mutant could not rescue the mutant phenotype:less sensitivity to ABA-and H2S-induced stomatal closure and Ca2+influx as well as increased water loss and decreased drought tolerance.Taken together,our study reveals a novel post-translational regulatory mechanism of ABA signaling whereby H2S persulfidates SnRK2.6 to promote ABA signaling and ABA-induced stomatal closure.
文摘Stomatal movements are critical in regulating gas exchange for photosynthesis and water balance between plant tissues and the atmosphere. The plant hormone abscisic acid （ABA） plays key roles in regulating stomatal closure under various abiotic stresses. In this study, we revealed a novel role of BAKI in guard cell ABA signaling. We found that the brassinosteroid （BR） signaling mutant bakl lost more water than wild- type plants and showed ABA insensitivity in stomatal closure. ABA-induced OST1 expression and reactive oxygen species （ROS） production were also impaired in bakl. Unlike direct treatment with H202, overex-pression of OST1 did not completely rescue the insensitivity of bakl to ABA. We demonstrated that BAK1 forms a complex with OST1 near the plasma membrane and that the BAKI/OST1 complex is increased in response to ABA in planta. Brassinolide, the most active BR, exerted a negative effect on ABA-induced formation of the BAK1/OST1 complex and OST1 expression. Moreover, we found that BAK1 and ABI1 oppositely regulate OST1 phosphorylation in vitro, and that ABI1 interacts with BAK1 and inhibits the interaction of BAK1 and OST1. Taken together, our results suggest that BAK1 regulates ABA-induced stomatal closure in guard cells.
