Novel methodology for quantitative assessment of the capacity for photoprotection in photosynthetic organisms
Lead Research Organisation:
Queen Mary University of London
Department Name: Sch of Biological and Chemical Sciences
Abstract
The dissipation of excess excitation energy (NPQ) in the photosynthetic membrane is a fundamental process that prevents damage to the photosynthetic membrane, particularly oxygen-evolving photosystem II reaction centers. However, exploiting NPQ for quantitative assessment, the prediction of plant wellbeing and for the possible improvement of photosynthesis has not occurred, partly due to a lack of knowledge concerning the nature and amplitude of the photoprotective component of NPQ (pNPQ) and its optimal level required for photosynthesis. Indeed, we urgently need methods that routinely separate components of NPQ that are crucially important from those not essential or even detrimental for plant survival and productivity. Here we propose to develop and test innovative, non-destructive and effective fluorescence techniques to isolate the beneficial (protective) component of NPQ in vivo and to determine its optimal level via generation of a number of quantitative parameters of light tolerance. We will use molecular and physiological approaches to apply these methods to leaf photosynthesis of a model plant species, Arabidopsis thaliana, and its various mutants. We will determine the impact of all NPQ components, photoprotective and photoinhibitory, on the state of the PSII reaction centers, electron transport, growth rate and biomass production and using mutant plants we will identify new targets for the forecasting and improvement of light energy utilization, stress resistance and overall plant wellbeing.
Technical Summary
Modelling suggests under certain circumstances photoprotective energy dissipation in the photosystem II (PSII) antenna (qE) may be responsible for reducing the yield of photosynthesis by up to 30%. This project will test this idea in two ways. Firstly, we will test whether qE is an unnecessary mechanism for plants grown under constant light intensity (e.g. commercial glasshouses) where photo-oxidative damage is unlikely. To test this we will grow Arabidopsis mutants that possess little or no qE (lut2npq1, npq1 and npq4) under various constant light intensities and compare their productivity, measured in terms of both growth rate, biomass and seed production, to the wild-type. We will quantify leaf area and PSII yield using non-invasive methods such as chlorophyll fluorescence imaging. In addition, the fluorescence lifetime of leaves will be used as an independent and absolute measure of energy storage efficiency and usage by PSII using picosecond time correlated single photon counting. The ability to turn increased PSII yield into carbon gain will be quantified by comparing the levels of stored sugars and carbohydrates in leaf tissue by spectroscopic assay. The second part of the project will test if plants grown under natural light conditions where the light intensity fluctuates rapidly and dramatically throughout the day suffer from the inability of qE to track adequately quickly these fluctuations. The slow relaxation of qE upon transition from high to low light undermines the photosynthetic yield leading to losses in productivity. Here we will compare Arabidopsis and rice mutants that show faster rates of qE relaxation than the wild-type (L17, szl1, asChyB) to understand if these phenotypes result in increases in productivity. To check this Arabidopsis and rice will be grown under fluctuating light conditions mimicking those found in the field and quantify their productivity by seed production, biomass and growth rate.
Planned Impact
Who will benefit from this research? How will they benefit from this research?
1. The Environment
The project will benefit the environment in several ways. Firstly, any increase in the productivity of UK agriculture will allow the home-grown share of the fruits and vegetables market to increase, thus reducing the amount imported from overseas. A decrease in fruit and vegetable imports will reduce the carbon footprint of the consumer by reducing food miles. The project also promises to reduce the necessary artificial light energy input into UK glasshouses, again reducing the carbon footprint. In addition, in the very near future, there will be a strongly increasing demand for sustainable energy for our society. The sun is the far biggest source of energy, and photosynthetic organisms in both land and aquatic environments are the foundations of a bio-based economy. Increases in photosynthetic productivity can benefit UK society by increasing the amount of biomass available for conversion into biofuels and increasing food security through higher crop yields.
2. The UK Agriculture Sector
The principle end users of this research will be in the commercial sectors associated with crops, including biofuels. The maximum predicted profit from the improvement of NPQ dynamics in the field for all UK crops could potentially reach £300M. The PI together Professor Conrad Mullineaux (QMUL) was a recipient of a grant from the Carbon Trust on Algal Biofuels Challenge (ABC) to explore certain marine algae for the use in the generation of biodiesel. It is possible that identified NPQ mutants will also be useful for increasing algal photosynthetic productivity especially where controlled environmental conditions are used in biorectors etc.
3. The UK Economy
In addition to increased profits from enhanced crop plant productivity the UK economy will also benefit from the project by providing training and experience for UK scientists and technicians in a multidisciplinary array of microscopic, spectroscopic, biochemical and other practical techniques. The skills they acquire will enable them to think of innovative, cross-discipline solutions to the crucial biological and environmental problems of the present and future, and to play a part in developing a successful bio-based economy.
4. Agrobiotech companies such as Syngenta
The project will benefit agrobiotechnology companies at home and abroad, who will be interested in genes identified by the project as targets for increased photosynthetic productivity. Potentially these companies can create mutants currently only available in Arabidopsis for crop plants and sell these under license to the domestic and global agriculture sector.
What will be done to ensure that they benefit from this research?
Dissemination of results: Publications in peer-reviewed international journals; Oral and poster contributions at international scientific meetings and workshops; the project will be described on the PI's website; (http://webspace.qmul.ac.uk/aruban); publicity of important finding via press releases from QMUL. We will also actively engage with a range of agrobiotech companies providing them with presentations of our findings, opening a dialogue on the future application of our research to crop plants.
Training: The training opportunities provided by this project will be greatly augmented by the participation of the PI in the HARVEST Marie Curie training Network of the EU FP7 programme. HARVEST brings together 15 top institutes from various disciplines working on the elementary regulation mechanisms in oxygenic photosynthesis, as well as academic groups and commercial enterprises working on new methodologies suitable for industrial and commercial exploitation of biosolar energy.
1. The Environment
The project will benefit the environment in several ways. Firstly, any increase in the productivity of UK agriculture will allow the home-grown share of the fruits and vegetables market to increase, thus reducing the amount imported from overseas. A decrease in fruit and vegetable imports will reduce the carbon footprint of the consumer by reducing food miles. The project also promises to reduce the necessary artificial light energy input into UK glasshouses, again reducing the carbon footprint. In addition, in the very near future, there will be a strongly increasing demand for sustainable energy for our society. The sun is the far biggest source of energy, and photosynthetic organisms in both land and aquatic environments are the foundations of a bio-based economy. Increases in photosynthetic productivity can benefit UK society by increasing the amount of biomass available for conversion into biofuels and increasing food security through higher crop yields.
2. The UK Agriculture Sector
The principle end users of this research will be in the commercial sectors associated with crops, including biofuels. The maximum predicted profit from the improvement of NPQ dynamics in the field for all UK crops could potentially reach £300M. The PI together Professor Conrad Mullineaux (QMUL) was a recipient of a grant from the Carbon Trust on Algal Biofuels Challenge (ABC) to explore certain marine algae for the use in the generation of biodiesel. It is possible that identified NPQ mutants will also be useful for increasing algal photosynthetic productivity especially where controlled environmental conditions are used in biorectors etc.
3. The UK Economy
In addition to increased profits from enhanced crop plant productivity the UK economy will also benefit from the project by providing training and experience for UK scientists and technicians in a multidisciplinary array of microscopic, spectroscopic, biochemical and other practical techniques. The skills they acquire will enable them to think of innovative, cross-discipline solutions to the crucial biological and environmental problems of the present and future, and to play a part in developing a successful bio-based economy.
4. Agrobiotech companies such as Syngenta
The project will benefit agrobiotechnology companies at home and abroad, who will be interested in genes identified by the project as targets for increased photosynthetic productivity. Potentially these companies can create mutants currently only available in Arabidopsis for crop plants and sell these under license to the domestic and global agriculture sector.
What will be done to ensure that they benefit from this research?
Dissemination of results: Publications in peer-reviewed international journals; Oral and poster contributions at international scientific meetings and workshops; the project will be described on the PI's website; (http://webspace.qmul.ac.uk/aruban); publicity of important finding via press releases from QMUL. We will also actively engage with a range of agrobiotech companies providing them with presentations of our findings, opening a dialogue on the future application of our research to crop plants.
Training: The training opportunities provided by this project will be greatly augmented by the participation of the PI in the HARVEST Marie Curie training Network of the EU FP7 programme. HARVEST brings together 15 top institutes from various disciplines working on the elementary regulation mechanisms in oxygenic photosynthesis, as well as academic groups and commercial enterprises working on new methodologies suitable for industrial and commercial exploitation of biosolar energy.
People |
ORCID iD |
Alexander Ruban (Principal Investigator) |
Publications
Belgio E
(2015)
Light-harvesting superstructures of green plant chloroplasts lacking photosystems.
in Plant, cell & environment
Belgio E
(2014)
Economic photoprotection in photosystem II that retains a complete light-harvesting system with slow energy traps.
in Nature communications
Benson SL
(2015)
An intact light harvesting complex I antenna system is required for complete state transitions in Arabidopsis.
in Nature plants
Brunet C
(2014)
Spectral radiation dependent photoprotective mechanism in the diatom Pseudo-nitzschia multistriata.
in PloS one
Carvalho FE
(2015)
Quantifying the dynamics of light tolerance in Arabidopsis plants during ontogenesis.
in Plant, cell & environment
Chandrasekaran R
(2014)
Light modulation of biomass and macromolecular composition of the diatom Skeletonema marinoi.
in Journal of biotechnology
Chmeliov J
(2016)
The nature of self-regulation in photosynthetic light-harvesting antenna.
in Nature plants
Chmeliov J
(2015)
An 'all pigment' model of excitation quenching in LHCII.
in Physical chemistry chemical physics : PCCP
Duffy CD
(2015)
Dissipative pathways in the photosystem-II antenna in plants.
in Journal of photochemistry and photobiology. B, Biology
Duffy CD
(2014)
Modeling the NMR signatures associated with the functional conformational switch in the major light-harvesting antenna of photosystem II in higher plants.
in Physical chemistry chemical physics : PCCP
Description | Various types and varieties of plants have been tested in order to determine what components of the photosynthetic apparatus are responsible to ensure plant light tolerance. the interplay between the repair cycle of the photosystem II RC and NPQ have been established within the time frame of ~1 hr. |
Exploitation Route | Has been described in the 'Impact' section. |
Sectors | Agriculture Food and Drink Energy |
URL | https://www.optisci.com/psp32.html |
Description | Since August 2014, A. Ruban has developed methodology to assess the effectiveness of nonphotochemical quenching in protecting the oxygen evolving photosystem II against excess light in plants. The methodology has been taken and enhanced into a new kit called PSP32 by an American company called Opti-Sciences Inc which is now being sold and distributed in the US and UK. The kit has a price range of £14k-£45k. |
First Year Of Impact | 2014 |
Sector | Agriculture, Food and Drink,Environment,Manufacturing, including Industrial Biotechology |
Impact Types | Economic |
Title | Quantifying light tolerance in the photosynthetic organisms. |
Description | Despite the fact that plants are sedentary organisms, their physiological processes can be extremely dynamic especially those involved in transforming the energy from sunlight into energy-carrying ATP molecules in cells through photosynthesis [1]. Bright sunlight can promptly damage the delicate light-harvesting machinery. Therefore plants have evolved a molecular process called nonphotochemical quenching (NPQ), which enables excess light energy to be channelled harmlessly into heat [2]. The current impact case is based on Ruban's novel theory that enables, for the first time, the use of chlorophyll fluorescence equipment to assess the effectiveness of NPQ in protecting the oxygen evolving photosystem II against excess light [3]. He developed a methodology that allows precise, non-destructive and simultaneous quantification of the photoprotective power of NPQ, the state of intactness of the photosystem II reaction centres and the efficiency of the photosynthetic electron transport chain [3-5]. Before this development lengthy, expensive and destructive procedures have been used for the assessment of photosystem II and none existed to quantify the effectiveness of NPQ [3]. The novel methodology is not only non-destructive, but also relatively cheap and fast. The applications of the novel procedure have so far included: determination of light tolerance by various plant and crop species and their mutants grown in different environments [6-8]; determination of the minimum levels of NPQ required to completely protect a plant against a given light intensity [5]; assessment of the optimum for protection levels of NPQ [5,7]; assessment of the dynamics of protective effectiveness of NPQ in ontogenesis [9]; distinguishing between the chlorophyll fluorescence components that are protective from the ones that correspond to the damaged photosynthetic apparatus [4,5,10] The plan is to distinguish between the two different types of damage to the photosynthetic apparatus - donor vs acceptor side damage to photosystem II reaction centre using the novel methodology; screen for the most high light tolerant plant species, investigate the combination of light and temperature stresses on the light tolerance of model plants and crops; assess the contribution of the photosystem II reaction centre repair mechanisms and NPQ to light tolerance of plants grown using variety of light regimes. The future applications will be the use of field monitoring fluorimeters to assess the protective power of NPQ in crops [11]; use of the imaging fluorescence technology for the high throughput phenomics [3]. [1] Ruban A. 2012 The Photosynthetic Membrane: Molecular Mechanisms and Biophysics of Light Harvesting. Oxford, UK: Wiley-Blackwell. [2] Ruban AV. 2016 Non-photochemical chlorophyll fluorescence quenching: mechanism and effectiveness in protection against photodamage. Plant Physiol. 170, 1903-1916. [3] Ruban, A.V. (2017) Quantifying the efficiency of photoprotection. Phil. Trans. Royal Society of London B. 372, 20160393. [4] Ruban, A.V., Murchie, E.H. (2012) Assessing the photoprotective effectiveness of non-photochemical chlorophyll fluorescence quenching: a new approach. Biochim. Biophys. Acta, 1817, 977-982. [5] Ruban, A.V. and Belgio, E. (2014) The relationship between maximum tolerated light intensity and non-photochemial chlorophyll fluorescence quenching: chloroplast gains and losses. Phil. Trans. Royal Society of London B, 369, 20130222. [6] Ware MA, Belgio E, Ruban AV. 2015 Photoprotective capacity of non-photochemical quenching in plants acclimated to different light intensities. Photosynth. Res. 126, 261-274. [7] Ware MA, Belgio E, Ruban AV. 2014 Comparison of the protective effectiveness of NPQ in Arabidopsis plants deficient in PsbS protein and zeaxanthin. J. Exp. Bot. 66, 1259-1270. [8] Ware MA, Dall'Osto L, Ruban AV. 2016 An in vivo quantitative comparison of photoprotection in Arabidopsis xanthophyll mutants. Frontiers in Plant Sci. 7, 841. [9] Carvalho FEL, Ware MA, Ruban AV. 2015 Quantifying the dynamics of light tolerance in Arabidopsis plants during ontogenesis. Plant Cell & Environment 38, 2603-2617. [10] Giovagnetti V, Ruban AV. 2015 Discerning the effects of photoinhibition and photoprotection on the rate of oxygen evolution in Arabidopsis leaves. J. Photochem. Photobiol. 152, 272-278. [11] Ruban, A.V. (2017) Crops on fast track for light. Nature 541, 36-37. |
Type Of Material | Technology assay or reagent |
Year Produced | 2014 |
Provided To Others? | Yes |
Impact | The methodology has been adopted by an American company Opti-Sciences Inc into a device called PSP32 which is sold and distributed in the US and UK [1]. The design and implementation of these units was informed by Ruban's research, and as is referenced in their brochure and flier. The price range for the kit is £14,000-£45,000 which is dependent on the complexity of the kit ordered. PSP32 was designed to meet the following aims: 1.) To make a system that provides a more cost effective solution for monitoring plant tolerance to high light over long periods of time, automatically. 2.) To make a system that allowed the use of a greater number of measuring head probes with a single system controller, to drive down the cost of measuring larger plant populations. 3.) To expand the measuring capability of the system, to allow it to measure a wider range of plant mechanisms, and measuring protocols, than existing technology. 4.) To update monitoring technology to take advantage of the latest science. 'We are confident that this instrument will be greatly welcomed by those undertaking large-scale, high-throughput plant phenotyping and breeding". This devise will be used for testing and breeding for features in crop plants which enable a higher yield of commercial crops from a piece of land, as well as breeding more resilient crops in the face of global climatic change, extreme weather events etc. The ability to enable researchers to monitor the photosynthetic 'health' of a plant through chlorophyll fluorescence is already proven to be highly valuable. With the PSP 32, researchers will have the opportunity to monitor as many as 32 plants or leaves simultaneously. This is designed to save both time and labour costs, as the system can be operated remotely through Wifi and samples are taken automatically, once the system is set up. It also becomes more cost effective than buying several, separate analysers - each PSP probe fits to one control unit, so each additional probe costs far less than an entire system.' - Stephanie Sidery, Opti-sciences Inc distributer in the UK. |
URL | https://www.optisci.com/psp32.html |
Description | Broadcast of the collaboration with Valoya and Microsoft companies |
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 | Media (as a channel to the public) |
Results and Impact | Industry collaboration drives Queen Mary research into higher yields in agricultural crops Scientists from the School of Biological and Chemical Sciences have teamed up with industry to create the next generation of lighting systems. Professor Alexander Ruban, Professor of Biophysics, collaborated with Finnish company Valoya and Microsoft to create a novel solution for simulation of natural outdoor light. Using Valoya's advanced LED lights, Microsoft Azure cloud platform and Internet-of-Things (IoT) technology, the system enables accurate replication of outdoor light conditions over time, while matching the spectrum and intensity of constantly changing natural light. |
Year(s) Of Engagement Activity | 2015 |
URL | https://www.qmul.ac.uk/sbbs/news/items/industry-collaboration-drives-queen-mary-research-into-higher... |
Description | Efficient Light-Harvesting of Plants: Conversation with Professor Alexander Ruban. World Scientific |
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 | Media (as a channel to the public) |
Results and Impact | Efficient Light-Harvesting of Plants: Conversation with Professor Alexander Ruban APBN editor, Carmen met Professor Alexander Ruban, who was invited to give a presentation of the dynamic light harvesting membrane, at 4th International Workshop on Solar Energy for Sustainability: Photosynthesis and Bioenergetics held in Nanyang Technological University (NTU), Singapore last March. Professor Alexander Ruban is a professor cum research fellow at Queen Mary, University of London. His lab focuses on the molecular mechanisms of light energy utilisation and management in the photosynthetic membrane. The major goal of his lab is to understand how biological matter is evolved to conduct a variety of intimate physical processes accompanying photosynthetic energy conversion and how structural properties of the photosynthetic light harvesting proteins govern flexibility and efficiency of photosynthesis. Following the tribute session for Professor Jan Anderson FRS, Prof. Ruban talked about the mechanisms of light harvesting and photoprotection in photosystem II - the molecular mechanism of non-photochemical chlorophyll fluorescence quenching, NPQ, its regulatory factors and significance in protection of the reaction centre from the photodamage. Amazed by the miracles of the natural dynamic molecular mechanism inside plants, we are glad to explore more on this topic through the interview with Prof. Ruban |
Year(s) Of Engagement Activity | 2016 |
URL | https://www.worldscientific.com/doi/abs/10.1142/S0219030316000501?journalCode=apbn |
Description | The reception that The Duke of York gave for President Bai, Chinese Academy of Sciences, at Buckingham Palace on 27th February 2017 |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Supporters |
Results and Impact | Bai Chunli, president of the Chinese Academy of Sciences, spoke about the President's International Fellowship Initiative on Monday in Buckingham Palace. Bai said it is the right time for Western scientists to do research in China. First launched in 2013, the initiative has given 2,800 scientists the chance to work in China in one of four categories: distinguished scientist, visiting scientist, postdoctoral researcher or international PhD student. Its support of the work of 205 Britons, like Sir Andre Geim, a Nobel Prize laureate, has included lecture trips and cooperative research at CAS. This year, 22 British scientists are expected to work in China. |
Year(s) Of Engagement Activity | 2017 |
URL | https://www.chinadaily.com.cn/world/2017-02/28/content_28381042.htm |