15 NSFBIO SAUR regulation of stomatal aperture
Lead Research Organisation:
University of Glasgow
Department Name: College of Medical, Veterinary, Life Sci
Abstract
Guard cells control photosynthesis and transpiration by regulating opening and closing of stomatal pores. We know much about how guard cells shrink in response to the drought stress hormone ABA, leading to stomatal closure. In contrast, we have sparse knowledge of the biochemical events by which guard cells swell to cause stomatal opening in response to light and diurnal rhythms. We have found that Arabidopsis SAUR (Small Auxin Up RNA) proteins can promote stomatal opening. This proposal will be to unravel under what conditions and by what mechanisms they do so.
SAUR genes are a large class in all land plants. Several Arabidopsis SAUR proteins localize to the plasma membrane and promote cell expansion. These proteins are normally short-lived, but can be stabilized in the plasma membrane. We know that closely related SAUR proteins promote growth by inhibiting membrane-associated protein phosphatases that otherwise dephosphorylate plasma membrane H+-ATPases at a key regulatory site and increase H+-ATPase proton pumping. The same SAURs also promote stomatal opening when expressed in guard cells and a subset of these are preferentially expressed in guard cells under conditions in which stomata are open, but are repressed by drought or ABA. By contrast, ABA activates other SAUR genes in guard cells which may have opposing effects on stomatal function. Thus, what we do not know is whether these opposing actions are unique, whether they overlap, or whether SAUR-mediated signalling affects other transport and homeostatic processes in guard cells.
Multiple transporters in both the plasma membrane and the tonoplast influence guard cell shrinking and swelling, and their activities often depend either directly or indirectly on the activation status of the others. Thus, to understand stomatal dynamics, it is essential to gain a global, systems view of guard cell transport and homeostasis. A major component of this project will exploit computational models that simulate these couplings using parameters based on experimental measurements. Starting points for current modelling will draw on past predictions that changes in H+-ATPase activity will have significant effects on stomatal aperture. For example, increased H+-ATPase activity in the model leads to slower stomatal closing at dusk and also to changed cytoplasmic concentrations of several other ions. Such knowledge will aid in experimental design and will also form a basis for subsequent validation.
The collaborating researchers have complementary expertise in guard cell physiology (Blatt), computational modeling (Blatt), biochemistry (Gray), genetics (Reed, Nagpal), and auxin response (Gray, Nagpal, Reed). The collaboration will pool resources and expertise developed in the three labs to make possible the multipronged approach.
SAUR genes are a large class in all land plants. Several Arabidopsis SAUR proteins localize to the plasma membrane and promote cell expansion. These proteins are normally short-lived, but can be stabilized in the plasma membrane. We know that closely related SAUR proteins promote growth by inhibiting membrane-associated protein phosphatases that otherwise dephosphorylate plasma membrane H+-ATPases at a key regulatory site and increase H+-ATPase proton pumping. The same SAURs also promote stomatal opening when expressed in guard cells and a subset of these are preferentially expressed in guard cells under conditions in which stomata are open, but are repressed by drought or ABA. By contrast, ABA activates other SAUR genes in guard cells which may have opposing effects on stomatal function. Thus, what we do not know is whether these opposing actions are unique, whether they overlap, or whether SAUR-mediated signalling affects other transport and homeostatic processes in guard cells.
Multiple transporters in both the plasma membrane and the tonoplast influence guard cell shrinking and swelling, and their activities often depend either directly or indirectly on the activation status of the others. Thus, to understand stomatal dynamics, it is essential to gain a global, systems view of guard cell transport and homeostasis. A major component of this project will exploit computational models that simulate these couplings using parameters based on experimental measurements. Starting points for current modelling will draw on past predictions that changes in H+-ATPase activity will have significant effects on stomatal aperture. For example, increased H+-ATPase activity in the model leads to slower stomatal closing at dusk and also to changed cytoplasmic concentrations of several other ions. Such knowledge will aid in experimental design and will also form a basis for subsequent validation.
The collaborating researchers have complementary expertise in guard cell physiology (Blatt), computational modeling (Blatt), biochemistry (Gray), genetics (Reed, Nagpal), and auxin response (Gray, Nagpal, Reed). The collaboration will pool resources and expertise developed in the three labs to make possible the multipronged approach.
Technical Summary
This project is to address the roles of SAUR proteins in auxin-associated signalling of guard cells. The project is divided so that the Reed/Nagpal and Gray labs will characterize expression patterns and subcellular localization of candidate Arabidopsis SAUR and associated proteins, and determine how light and ABA may regulate their abundance or localization. They will also test whether these proteins interact, and assess the regulatory consequences of such interaction. Finally, they will generate mutant and transgenic plants with increased or decreased activity of these proteins.
The Blatt lab will vary selected parameters of guard cell systems models to predict which ion concentrations may be altered in the guard cells of the mutant and transgenic plants. The Blatt lab will also perform electrophysiological experiments to measure K+, Cl-, and H+ and other ion transport activities in guard cells to assess and refine the above models and to guide experimental analysis of key mutant lines. These analyses should allow fitting of the model to match the observed results, and make predictions about effects of additional genetic or physiological perturbations. Modelling will thus allow the workers to focus on meaningful experiments, and point to unanticipated emergent properties of the system. Cases where the experiments do not validate the predictions will also be interesting as they will suggest alternate mechanisms by which SAUR proteins may act, or needed adjustment of the parameters or couplings in the model.
Combined modeling, biochemical, genetic and electrophysiological approaches should yield important insight into stomatal opening mechanisms, and they may suggest synthetic biological approaches to manipulating stomatal kinetics for improved crop efficiencies.
The Blatt lab will vary selected parameters of guard cell systems models to predict which ion concentrations may be altered in the guard cells of the mutant and transgenic plants. The Blatt lab will also perform electrophysiological experiments to measure K+, Cl-, and H+ and other ion transport activities in guard cells to assess and refine the above models and to guide experimental analysis of key mutant lines. These analyses should allow fitting of the model to match the observed results, and make predictions about effects of additional genetic or physiological perturbations. Modelling will thus allow the workers to focus on meaningful experiments, and point to unanticipated emergent properties of the system. Cases where the experiments do not validate the predictions will also be interesting as they will suggest alternate mechanisms by which SAUR proteins may act, or needed adjustment of the parameters or couplings in the model.
Combined modeling, biochemical, genetic and electrophysiological approaches should yield important insight into stomatal opening mechanisms, and they may suggest synthetic biological approaches to manipulating stomatal kinetics for improved crop efficiencies.
Planned Impact
This proposal is for fundamental research developing new concepts at the core of ideas emerging within the international cell biology community. The research should stimulate thinking about these topics and help facilitate a paradigm shift in approach. These studies will also extend recent developments by MRB and colleagues Reed/Nagpal and Gray in expanding our understanding of stomatal regulation by SAUR proteins and in its modelling. Thus, the research is expected to benefit fundamental researchers as well as industry through conceptual developments as well as the introduction of new technologies for the analysis of complex systems in vitro and in vivo. The research will feed into higher education programmes through research training at the postgraduate and postdoctoral levels. Finally it will help guide future efforts in applications to agricultural/industrial systems. MRB has established links with industrial/technology transfer partners (e.g. Agrisera, Plant Bioscience) and research institutes (JHI, NIH and JIC) to take advantage of these developments. Further details of these, and additional impacts will be found in the attached documentation.
People |
ORCID iD |
Michael Blatt (Principal Investigator) |
Publications
Zhao C
(2019)
Evolution of chloroplast retrograde signaling facilitates green plant adaptation to land.
in Proceedings of the National Academy of Sciences of the United States of America
Zhang B
(2018)
A GPI Signal Peptide-Anchored Split-Ubiquitin (GPS) System for Detecting Soluble Bait Protein Interactions at the Membrane.
in Plant physiology
Zhang B
(2019)
Dual Sites for SEC11 on the SNARE SYP121 Implicate a Binding Exchange during Secretory Traffic.
in Plant physiology
Zhang B
(2017)
VAMP721 Conformations Unmask an Extended Motif for K+ Channel Binding and Gating Control.
in Plant physiology
Wong J
(2021)
SAUR proteins and PP2C.D phosphatases regulate H+-ATPases and K+ channels to control stomatal movements
in Plant Physiology
Wang Y
(2017)
Unexpected Connections between Humidity and Ion Transport Discovered Using a Model to Bridge Guard Cell-to-Leaf Scales.
in The Plant cell
Waghmare S
(2019)
K+ Channel-SEC11 Binding Exchange Regulates SNARE Assembly for Secretory Traffic.
in Plant physiology
Waghmare S
(2018)
SNAREs SYP121 and SYP122 Mediate the Secretion of Distinct Cargo Subsets.
in Plant physiology
Vialet-Chabrand SRM
(2017)
Temporal Dynamics of Stomatal Behavior: Modeling and Implications for Photosynthesis and Water Use.
in Plant physiology
Vialet-Chabrand S
(2017)
Global Sensitivity Analysis of OnGuard Models Identifies Key Hubs for Transport Interaction in Stomatal Dynamics.
in Plant physiology
Description | The research has demonstrated that one of the main pathways mediated through control of membrane transport in guard cells is a highly complex process, not a simple linear process as previously thought. Guard cells regulate gas exchange for photosynthesis and are a key relatory point for control of water loss from plants. An important finding from these studies is that the SAUR pathway for regulating plant cell development also plays a role in short-term regulation of gas exchange. Thus, this knowledge adds key information that will help in guiding future efforts towards maximising plant growth under water-limiting conditions |
Exploitation Route | The information gained through this research project adds key information that will help in guiding future efforts towards maximising plant growth under water-limiting conditions. |
Sectors | Agriculture Food and Drink Other |
URL | http://psrg.org.uk |
Title | 2in1 vector systems |
Description | Synthetic biology vectors for transient and stable transformation with quantitative visual reporting on cell-by-cell basis |
Type Of Material | Technology assay or reagent |
Year Produced | 2009 |
Provided To Others? | Yes |
Impact | Multiple publications from my own research group and over 100 research groups worldwide Vector system distributions to more than 500 research groups worldwide |
URL | http://psrg.org.uk |
Title | EZ-Rhizo |
Description | Computer software tool for quantitative measurement and analysis of root growth/development |
Type Of Material | Physiological assessment or outcome measure |
Year Produced | 2010 |
Provided To Others? | Yes |
Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
URL | http://psrg.org.uk |
Title | Henry |
Description | Software for electrophysiology and imaging data aquisition and analysis |
Type Of Material | Technology assay or reagent |
Provided To Others? | Yes |
Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
URL | http://psrg.org.uk |
Title | Multicistronic vector systems |
Description | Synthetic biology vector systems for transient and stable transformation for expressing multiple, tagged proteins and for quantitative analysis of membrane traffic and transport |
Type Of Material | Technology assay or reagent |
Year Produced | 2010 |
Provided To Others? | Yes |
Impact | Multiple publications from my own research group and over 100 research groups worldwide Vector system distributions to more than 500 research groups worldwide |
URL | http://psrg.org.uk |
Title | OnGuard |
Description | Systems biology software for quantitative modelling of cellular transport and homeostasis |
Type Of Material | Physiological assessment or outcome measure |
Year Produced | 2012 |
Provided To Others? | Yes |
Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
URL | http://psrg.org.uk |
Title | SUS vector systems |
Description | Synthetic biological vector systems for protein-protein interaction screening |
Type Of Material | Technology assay or reagent |
Year Produced | 2010 |
Provided To Others? | Yes |
Impact | Multiple publications from my own research group and over 100 research groups worldwide Vector system distributions to more than 500 research groups worldwide |
URL | http://psrg.org.uk |
Title | Software tools for electrophysiology and imaging |
Description | The laboratory continues to develop and refine software/hardware tools for data acquisition and analysis relevant to electrophysiology, single-cell imaging and analysis. These activities are long-standing and open-ended, and develop in line with the current research activities and needs of the laboratory. All software and related packages are made freely available to the research community through the laboratory website at psrg.org.uk |
Type Of Material | Technology assay or reagent |
Provided To Others? | Yes |
Impact | The various software tools and packages have furthered the research activities of the laboratory since the 1990s and continue to provide key support and drivers for advancing much of current research. These tools and packages are disseminated, on average, to over 100 laboratories per year. |
URL | http://psrg.org.uk |
Title | EZ-Rhizo |
Description | Software for quantitative trait analysis and acquisition for root growth/development |
Type Of Material | Database/Collection of data |
Year Produced | 2010 |
Provided To Others? | Yes |
Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
URL | http://psrg.org.uk |
Title | Henry |
Description | Software package for electrophysiology and imaging data acquisition and analysis |
Type Of Material | Data handling & control |
Provided To Others? | Yes |
Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
URL | http://psrg.org.uk |
Title | OnGuard |
Description | Quantitative systems biology modelling of cellular transport and homeostasis |
Type Of Material | Computer model/algorithm |
Year Produced | 2012 |
Provided To Others? | Yes |
Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
URL | http://psrg.org.uk |
Title | SDM-assist |
Description | Software for molecular primer design that enables introduction of silent markers for molecular cloning |
Type Of Material | Data analysis technique |
Year Produced | 2013 |
Provided To Others? | Yes |
Impact | Multiple publications from my own research group and research groups worldwide Online distribution has been accessed through the laboratory website with site views at a rate of >500 per month |
URL | http://psrg.org.uk |
Description | PBL |
Organisation | Plant Bioscience Limited Technology |
Country | United Kingdom |
Sector | Private |
PI Contribution | IPR on ABA receptor technology and ABA signalling |
Collaborator Contribution | Funding related to IPR on ABA receptor technology and ABA signalling |
Impact | Multiple outcomes in publications and industrial contacts |
Description | PSG |
Organisation | POSCO - South Korea |
Country | Korea, Republic of |
Sector | Private |
PI Contribution | Base support for meetings and exchange of materials |
Collaborator Contribution | Base support for meetings and exchange of materials |
Impact | Base support for meetings and exchange of materials |
Title | Software tools and packages for electrophysiology and imaging |
Description | The laboratory continues to develop and refine software/hardware tools for data acquisition and analysis relevant to electrophysiology, single-cell imaging and analysis. These activities are long-standing and open-ended, and develop in line with the current research activities and needs of the laboratory. All software and related packages are made freely available to the research community through the laboratory website at psrg.org.uk |
Type Of Technology | Software |
Impact | The various software tools and packages have furthered the research activities of the laboratory since the 1990s and continue to provide key support and drivers for advancing much of current research. These tools and packages are disseminated, on average, to over 100 laboratories per year. |
URL | http://psrg.org.uk |
Description | International online services |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Prof. Blatt and members of his laboratory have contributed to various media events over the years, including online interview contributions (e.g. People behind the Science, a US-based media program) |
Year(s) Of Engagement Activity | Pre-2006,2006,2008,2011,2015,2016,2017,2018 |
Description | Invited presentations |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | I regularly speak to audiences, from small groups (5-20) to large audiences (>1000) in a variety of settings. In addition to teaching and extramural activities associated with the university, I also speak on invitation to national and international groups a number of times each year and in a variety of settings, academic as well as public. I also reach audiences through short video presentations mounted on the web, these primarily via my laboratory website and the ASPB websites. Anyone reading this entry is welcome to visit these sites to learn more. The impacts arising from my presentations are varied. For example, a common consequence of my speaking in academic settings is to attract potential researchers to visit my laboratory and, frequently, to interest potential collaborators and students/postdocs to my research group. At scientific meetings, my talks often attract interest also from researchers interested in the various tools and materials that my research has produced, including the various vector systems and software packages that I |
Year(s) Of Engagement Activity | Pre-2006,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018 |
URL | http://psrg.org.uk |
Description | Schools and displays |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | Yes |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | As these were multiple events, this question is not informative or useful. Participants varied from numbers in the tens to several thousands Extensive training of participating laboratory members as well as broad scope reach to schools and communities, in the case of the GCC science days to the west of Scotland and in the case of the IFPD activities to audiences within and outside the UK |
Year(s) Of Engagement Activity | 2010,2011,2012,2013,2014,2015,2016,2017,2018 |
URL | http://psrg.org.uk |
Description | Teaching Tools |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | Yes |
Geographic Reach | International |
Primary Audience | Schools |
Results and Impact | The PI has supported the editor in developing these tools since their inception in 2009 and has contributed to recent tools relating to membranes and transport education The Tool received an international award in 2010 for excellence in education and has an acknowledged takeup worldwide in over 3000 institutions |
Year(s) Of Engagement Activity | 2009,2010,2011,2012,2013,2014,2015,2016,2017,2018 |
URL | http://psrg.org.uk |
Description | Teaching Tools |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | Yes |
Geographic Reach | International |
Primary Audience | Schools |
Results and Impact | The PI has supported the editor in developing these tools since their inception in 2009 and has contributed to recent tools relating to membranes and transport education The Tool received an international award in 2010 for excellence in education and has an acknowledged takeup worldwide in over 3000 institutions |
Year(s) Of Engagement Activity | 2009,2010,2011,2012,2013,2014,2015,2016,2017,2018 |
URL | http://psrg.org.uk |