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.

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.

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.

Publications

10 25 50
 
Description The research ongoing 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. 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