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Silva‐Alvim FAL, Alvim JC, Harvey A, Blatt MR. Speedy stomata of a C 4 plant correlate with enhanced K + channel gating. PLANT, CELL & ENVIRONMENT 2024; 47:817-831. [PMID: 38013592 PMCID: PMC10953386 DOI: 10.1111/pce.14775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 11/08/2023] [Accepted: 11/15/2023] [Indexed: 11/29/2023]
Abstract
Stomata are microscopic pores at the surface of plant leaves that facilitate gaseous diffusion to support photosynthesis. The guard cells around each stoma regulate the pore aperture. Plants that carry out C4 photosynthesis are usually more resilient than C3 plants to stress, and their stomata operate over a lower dynamic range of CO2 within the leaf. What makes guard cells of C4 plants more responsive than those of C3 plants? We used gas exchange and electrophysiology, comparing stomatal kinetics of the C4 plant Gynandropsis gynandra and the phylogenetically related C3 plant Arabidopsis thaliana. We found, with varying CO2 and light, that Gynandropsis showed faster changes in stomata conductance and greater water use efficiency when compared with Arabidopsis. Electrophysiological analysis of the dominant K+ channels showed that the outward-rectifying channels, responsible for K+ loss during stomatal closing, were characterised by a greater maximum conductance and substantial negative shift in the voltage dependence of gating, indicating a reduced inhibition by extracellular K+ and enhanced capacity for K+ flux. These differences correlated with the accelerated stomata kinetics of Gynandropsis, suggesting that subtle changes in the biophysical properties of a key transporter may prove a target for future efforts to engineer C4 stomatal kinetics.
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Affiliation(s)
| | - Jonas Chaves Alvim
- Laboratory of Plant Physiology and Biophysics, Bower BuildingUniversity of GlasgowGlasgowUK
| | - Andy Harvey
- Physics & AstronomyUniversity of GlasgowGlasgowUK
| | - Michael R. Blatt
- Laboratory of Plant Physiology and Biophysics, Bower BuildingUniversity of GlasgowGlasgowUK
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Long SP, Taylor SH, Burgess SJ, Carmo-Silva E, Lawson T, De Souza AP, Leonelli L, Wang Y. Into the Shadows and Back into Sunlight: Photosynthesis in Fluctuating Light. ANNUAL REVIEW OF PLANT BIOLOGY 2022; 73:617-648. [PMID: 35595290 DOI: 10.1146/annurev-arplant-070221-024745] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Photosynthesis is an important remaining opportunity for further improvement in the genetic yield potential of our major crops. Measurement, analysis, and improvement of leaf CO2 assimilation (A) have focused largely on photosynthetic rates under light-saturated steady-state conditions. However, in modern crop canopies of several leaf layers, light is rarely constant, and the majority of leaves experience marked light fluctuations throughout the day. It takes several minutes for photosynthesis to regain efficiency in both sun-shade and shade-sun transitions, costing a calculated 10-40% of potential crop CO2 assimilation. Transgenic manipulations to accelerate the adjustment in sun-shade transitions have already shown a substantial productivity increase in field trials. Here, we explore means to further accelerate these adjustments and minimize these losses through transgenic manipulation, gene editing, and exploitation of natural variation. Measurement andanalysis of photosynthesis in sun-shade and shade-sun transitions are explained. Factors limiting speeds of adjustment and how they could be modified to effect improved efficiency are reviewed, specifically nonphotochemical quenching (NPQ), Rubisco activation, and stomatal responses.
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Affiliation(s)
- Stephen P Long
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA;
- Departments of Plant Biology and Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom
| | - Samuel H Taylor
- Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom
| | - Steven J Burgess
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA;
| | | | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester, United Kingdom
| | - Amanda P De Souza
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA;
| | - Lauriebeth Leonelli
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA;
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Yu Wang
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA;
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Flütsch S, Wang Y, Takemiya A, Vialet-Chabrand SRM, Klejchová M, Nigro A, Hills A, Lawson T, Blatt MR, Santelia D. Guard Cell Starch Degradation Yields Glucose for Rapid Stomatal Opening in Arabidopsis. THE PLANT CELL 2020; 32:2325-2344. [PMID: 32354788 PMCID: PMC7346545 DOI: 10.1105/tpc.18.00802] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 03/25/2020] [Accepted: 04/23/2020] [Indexed: 05/18/2023]
Abstract
Starch in Arabidopsis (Arabidopsis thaliana) guard cells is rapidly degraded at the start of the day by the glucan hydrolases α-AMYLASE3 (AMY3) and β-AMYLASE1 (BAM1) to promote stomatal opening. This process is activated via phototropin-mediated blue light signaling downstream of the plasma membrane H+-ATPase. It remains unknown how guard cell starch degradation integrates with light-regulated membrane transport processes in the fine control of stomatal opening kinetics. We report that H+, K+, and Cl- transport across the guard cell plasma membrane is unaltered in the amy3 bam1 mutant, suggesting that starch degradation products do not directly affect the capacity to transport ions. Enzymatic quantification revealed that after 30 min of blue light illumination, amy3 bam1 guard cells had similar malate levels as the wild type, but had dramatically altered sugar homeostasis, with almost undetectable amounts of Glc. Thus, Glc, not malate, is the major starch-derived metabolite in Arabidopsis guard cells. We further show that impaired starch degradation in the amy3 bam1 mutant resulted in an increase in the time constant for opening of 40 min. We conclude that rapid starch degradation at dawn is required to maintain the cytoplasmic sugar pool, clearly needed for fast stomatal opening. The conversion and exchange of metabolites between subcellular compartments therefore coordinates the energetic and metabolic status of the cell with membrane ion transport.
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Affiliation(s)
- Sabrina Flütsch
- Institute of Integrative Biology, Eidgenössische Technische Hochschule (ETH) Zürich, CH-8092 Zürich, Switzerland
- Department of Plant and Microbial Biology, University of Zürich, CH-8008, Zürich, Switzerland
| | - Yizhou Wang
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Atsushi Takemiya
- Department of Biology, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 753-8512 Yamaguchi, Japan
| | | | - Martina Klejchová
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Arianna Nigro
- Department of Plant and Microbial Biology, University of Zürich, CH-8008, Zürich, Switzerland
| | - Adrian Hills
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester, CO4 3SQ, United Kingdom
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Diana Santelia
- Institute of Integrative Biology, Eidgenössische Technische Hochschule (ETH) Zürich, CH-8092 Zürich, Switzerland
- Department of Plant and Microbial Biology, University of Zürich, CH-8008, Zürich, Switzerland
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Eisenach C, Chen ZH, Grefen C, Blatt MR. The trafficking protein SYP121 of Arabidopsis connects programmed stomatal closure and K⁺ channel activity with vegetative growth. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 69:241-51. [PMID: 21914010 DOI: 10.1111/j.1365-313x.2011.04786.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The vesicle-trafficking protein SYP121 (SYR1/PEN1) was originally identified in association with ion channel control at the plasma membrane of stomatal guard cells, although stomata of the Arabidopsis syp121 loss-of-function mutant close normally in ABA and high Ca²⁺. We have now uncovered a set of stomatal phenotypes in the syp121 mutant that reduce CO₂ assimilation, slow vegetative growth and increase water use efficiency in the whole plant, conditional upon high light intensities and low relative humidity. Stomatal opening and the rise in stomatal transpiration of the mutant was delayed in the light and following Ca²⁺-evoked closure, consistent with a constitutive form of so-called programmed stomatal closure. Delayed reopening was observed in the syp121, but not in the syp122 mutant lacking the homologous gene product; the delay was rescued by complementation with wild-type SYP121 and was phenocopied in wild-type plants in the presence of the vesicle-trafficking inhibitor Brefeldin A. K⁺ channel current that normally mediates K⁺ uptake for stomatal opening was suppressed in the syp121 mutant and, following closure, its recovery was slowed compared to guard cells of wild-type plants. Evoked stomatal closure was accompanied by internalisation of GFP-tagged KAT1 K⁺ channels in both wild-type and syp121 mutant guard cells, but their subsequently recycling was slowed in the mutant. Our findings indicate that SYP121 facilitates stomatal reopening and they suggest that K⁺ channel traffic and recycling to the plasma membrane underpins the stress memory phenomenon of programmed closure in stomata. Additionally, they underline the significance of vesicle traffic for whole-plant water use and biomass production, tying SYP121 function to guard cell membrane transport and stomatal control.
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Affiliation(s)
- Cornelia Eisenach
- Laboratory of Plant Physiology and Biophysics, Institute of Molecular Cell and Systems Biology, Bower Building, University of Glasgow, Glasgow G12 8QQ, UK
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Wang D, Li XF, Zhou ZJ, Feng XP, Yang WJ, Jiang DA. Two Rubisco activase isoforms may play different roles in photosynthetic heat acclimation in the rice plant. PHYSIOLOGIA PLANTARUM 2010; 139:55-67. [PMID: 20059735 DOI: 10.1111/j.1399-3054.2009.01344.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Studies on some plant species have shown that increasing the growth temperature gradually or pretreating with high temperature can lead to obvious photosynthetic acclimation to high temperature. To test whether this acclimation arises from heat adaptation of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39) activation mediated by Rubisco activase (RCA), gene expression of RCA large isoform (RCA(L)) and RCA small isoform (RCA(S)) in rice was determined using a 4-day heat stress treatment [40/30 degrees C (day/night)] followed by a 3-day recovery under control conditions [30/22 degrees C (day/night)]. The heat stress significantly induced the expression of RCA(L) as determined by both mRNA and protein levels. Correlative analysis indicated that RCA(S) protein content was extremely significantly related to Rubisco initial activity and net photosynthetic rate (Pn) under both heat stress and normal conditions. Immunoblot analysis of the Rubisco-RCA complex revealed that the ratio of RCA(L) to Rubisco increased markedly in heat-acclimated rice leaves. Furthermore, transgenic rice plants expressing enhanced amounts of RCA(L) exhibited higher thermotolerance in Pn and Rubisco initial activity and grew better at high temperature than wild-type (WT) plants and transgenic rice plants expressing enhanced amounts of RCA(S). Under normal conditions, the transgenic rice plants expressing enhanced amounts of RCA(S) showed higher Pn and produced more biomass than transgenic rice plants expressing enhanced amounts of RCA(L) and wild-type plants. Together, these suggest that the heat-induced RCA(L) may play an important role in photosynthetic acclimation to moderate heat stress in vivo, while RCA(S) plays a major role in maintaining Rubisco initial activity under normal conditions.
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Affiliation(s)
- Dun Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
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Lee KR, Roh KS. Influence of cadmium on rubisco activation inCanavalia ensiformis L. leaves. BIOTECHNOL BIOPROC E 2003. [DOI: 10.1007/bf02940263] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Meng Q, Siebke K, Lippert P, Baur B, Mukherjee U, Weis E. Sink-source transition in tobacco leaves visualized using chlorophyll fluorescence imaging. THE NEW PHYTOLOGIST 2001; 151:585-595. [PMID: 33853257 DOI: 10.1046/j.0028-646x.2001.00224.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
• The sink-source transition of developing Nicotiana tabacum (tobacco) leaves was studied here using chlorophyll fluorescence imaging. • In accordance with leaf development, the quantum efficiency of PSII, showed a steep gradient across the leaf with increasing values towards the tip. • The linear electron transport rate (ETR) saturated at higher CO2 concentrations in the younger, than in the mature, part of the leaf, probably due to a lower Rubisco activity or a higher CO2 diffusion resistance. • The induction of ETR at CO2 concentrations near the compensation point after long-term dark adaptation of the young leaf, showed distinct responses; ETR rose rapidly in the basal but more slowly in the apical regions. There was a correlation between fast induction and carbohydrate import, as measured by 14 C-translocation. In the basal regions, larger pools of metabolic intermediates are expected due to imported carbohydrates. These might be used in the Calvin cycle directly after dark-light transition providing the electron acceptors for the faster induction of ETR. Additionally, a higher mitochondrial respiration can provide CO2 for the Calvin cycle in these regions.
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Affiliation(s)
- Qingwei Meng
- Institut für Botanik, Universität Münster Schlossgarten 3, D-48149 Münster, Germany; Present address: College of Life Science, Shandong Agricultural University, Taian, Shandong Province, 271018, PR China
| | | | - Peter Lippert
- Institut für Botanik, Universität Münster Schlossgarten 3, D-48149 Münster, Germany; Present address: College of Life Science, Shandong Agricultural University, Taian, Shandong Province, 271018, PR China
| | - Bernhard Baur
- Institut für Botanik, Universität Münster Schlossgarten 3, D-48149 Münster, Germany; Present address: College of Life Science, Shandong Agricultural University, Taian, Shandong Province, 271018, PR China
| | - Ute Mukherjee
- Institut für Botanik, Universität Münster Schlossgarten 3, D-48149 Münster, Germany; Present address: College of Life Science, Shandong Agricultural University, Taian, Shandong Province, 271018, PR China
| | - Engelbert Weis
- Institut für Botanik, Universität Münster Schlossgarten 3, D-48149 Münster, Germany; Present address: College of Life Science, Shandong Agricultural University, Taian, Shandong Province, 271018, PR China
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8
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Hammond ET, Andrews TJ, Woodrow IE. Regulation of ribulose-1,5-bisphosphate Carboxylase/Oxygenase by carbamylation and 2-carboxyarabinitol 1-phosphate in tobacco: insights from studies of antisense plants containing reduced amounts of rubisco activase. PLANT PHYSIOLOGY 1998; 118:1463-71. [PMID: 9847122 PMCID: PMC34764 DOI: 10.1104/pp.118.4.1463] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/1998] [Accepted: 09/08/1998] [Indexed: 05/18/2023]
Abstract
The regulation of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity by 2-carboxyarabinitol 1-phosphate (CA1P) was investigated using gas-exchange analysis of antisense tobacco (Nicotiana tabacum) plants containing reduced levels of Rubisco activase. When an increase in light flux from darkness to 1200 &mgr;mol quanta m-2 s-1 was followed, the slow increase in CO2 assimilation by antisense leaves contained two phases: one represented the activation of the noncarbamylated form of Rubisco, which was described previously, and the other represented the activation of the CA1P-inhibited form of Rubisco. We present evidence supporting this conclusion, including the observation that this second phase, like CA1P, is only present following darkness or very low light flux. In addition, the second phase of CO2 assimilation was correlated with leaf CA1P content. When this novel phase was resolved from the CO2 assimilation trace, most of it was found to have kinetics similar to the activation of the noncarbamylated form of Rubisco. Additionally, kinetics of the novel phase indicated that the activation of the CA1P-inhibited form of Rubisco proceeds faster than the degradation of CA1P by CA1P phosphatase. These results may be significant with respect to current models of the regulation of Rubisco activity by Rubisco activase.
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Affiliation(s)
- ET Hammond
- School of Botany, The University of Melbourne, Parkville, Victoria 3052, Australia (E.T.H., I.E.W.)
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Sassenrath-Cole GF, Pearcy RW. Regulation of Photosynthetic Induction State by the Magnitude and Duration of Low Light Exposure. PLANT PHYSIOLOGY 1994; 105:1115-1123. [PMID: 12232269 PMCID: PMC159439 DOI: 10.1104/pp.105.4.1115] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
This study was undertaken to examine the dependence of the regulatory enzymes of photosynthetic induction on photon flux density (PFD) exposure in soybean (Glycine max L.). The induction state varies as a function of both the magnitude and duration of the PFD levels experienced prior to an increase in PFD. The photosynthetic induction state results from the combined activity of separate processes that each in turn depend on prior PFD environment in different ways. Direct measurement of enzyme activities coupled with determination of in situ metabolite pool sizes indicated that the fast-induction component was associated with the activation state of stromal fructose-1,6-bisphosphatase (FBPase, EC 3.1.3.11) and showed rapid deactivation in the dark and at low PFD. The fast-induction component was activated at low PFD levels, around 70 [mu]mol photons m-2 s-1. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 2.7.1.19) deactivated very slowly in the dark and required higher PFD for activation. Both enzymes saturated at lower PFD than did photosynthesis, around 400 [mu]mol photons m-2 s-1. Ribulose-5-phosphate kinase (EC 2.7.1.19) appeared never to be limiting to photosynthesis, and saturated at much lower PFD than either FBPase or Rubisco. Determination of photosynthetic metabolite pool sizes from leaves at different positions within a soybean canopy showed a limitation to carbon uptake at the stromal FBPase and possibly the sedoheptulose-1,7-bisphosphatase (EC 3.1.3.37) in shade leaves upon initial illumination at saturating PFD levels.
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Mott KA, Woodrow IE. Effects of O2 and CO2 on Nonsteady-State Photosynthesis (Further Evidence for Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Limitation). PLANT PHYSIOLOGY 1993; 102:859-866. [PMID: 12231872 PMCID: PMC158857 DOI: 10.1104/pp.102.3.859] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The effects of CO2 and O2 on nonsteady-state photosynthesis following an increase in photosynthetic photon flux density (PPFD) were examined in Spinacia oleracea to investigate the hypotheses that (a) a slow exponential phase (the ribulose-1,5-bisphosphate carboxylase/oxygenase [Rubisco] phase) of nonsteady-state photosynthesis is primarily limited by Rubisco activity and (b) Rubisco activation involves two sequential, light-dependent processes as described in a previous study (I.E. Woodrow, K.A. Mott [1992] Plant Physiol 99: 298-303). Photosynthesis was found to be sensitive to O2 during the Rubisco phase in the approach of photosynthesis to steady state. Analyses of this sensitivity to O2 showed that the control coefficient for Rubisco was approximately equal to 1 during this phase, suggesting that Rubisco was the primary limitation to photosynthesis. O2 had almost no effect on the kinetics (described using a relaxation time, [tau] of the Rubisco phase for leaves starting in darkness or for leaves starting in low PPFD, but [tau] was substantially higher in the former case. CO2 was found to affect both the rate of photosynthesis and the magnitude of [tau] for the Rubisco phase. The [tau] value for the Rubisco phase was found to be negatively correlated with intercellular CO2 concentration (ci), and leaves starting in darkness had higher values of [tau] at any ci than leaves starting in low PPFD. The effects of CO2 and O2 on the Rubisco phase are consistent with the existence of two sequential, light-dependent processes in the activation of Rubisco if neither process is sensitive to O2 and only the second process is sensitive to CO2. The implications of the data for the mechanism of Rubisco activation and for the effects of stomatal conductance on nonsteady-state photosynthesis are discussed.
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Affiliation(s)
- K. A. Mott
- Biology Department, Utah State University, Logan, Utah 84322-5303 (K.A.M.)
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Lan Y, Woodrow IE, Mott KA. Light-dependent changes in ribulose bisphosphate carboxylase activase activity in leaves. PLANT PHYSIOLOGY 1992; 99:304-9. [PMID: 16668866 PMCID: PMC1080440 DOI: 10.1104/pp.99.1.304] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
An assay for the activity of ribulose bisphosphate carboxylase (Rubisco) activase in crude leaf extracts was developed. The assay is based on a spectrophotometric assay of Rubisco, and activase activity (in nanomoles activated Rubisco per minute per milligram chlorophyll) was calculated from the rate of increase in Rubisco activity over time. Activase activity measurements were made using samples from spinach (Spinacia oleracea) leaves undergoing (a) steady-state photosynthesis at various photon flux density (PFD) values and (b) nonsteady-state photosynthesis following an increase from darkness to a high PFD. Analysis of these samples showed that steady-state Rubisco activase activity was relatively low in darkness, increased with PFD, and saturated below 300 micromoles per square meter per second. Rubisco activity (measured spectrophotometrically) was also found to be low in darkness and to increase with PFD, but it saturated at much higher PFD values (approximately 1000 micromoles per square meter per second) along with the rate of photosynthesis. Following an increase in PFD from darkness to 650 micromoles per square meter per second, activase activity increased more or less linearly over a period of 5 to 6 minutes, after which it was constant. Rubisco activity, however, increased more slowly. The light-dependence of Rubisco activase is consistent with previous gas-exchange data showing two interdependent processes in the activation of Rubisco following an increase in PFD.
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Affiliation(s)
- Y Lan
- Biology Department, Utah State University, Logan, Utah 84322-5305
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