BBSRC-CASE Studentship
Lead Research Organisation:
University of Cambridge
Department Name: Plant Sciences
Abstract
The interdependent regulation between photosynthesis and circadian rhythms in cereals
People |
ORCID iD |
| Alex Webb (Primary Supervisor) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| BB/M015416/1 | 01/10/2015 | 30/09/2019 | |||
| 1642920 | Studentship | BB/M015416/1 | 01/10/2015 | 30/09/2019 |
| Description | The circadian clock is an endogenous timing mechanism that allows organisms to coordinate physical and behavioural processes with the natural light dark cycle. Synchronisation between the circadian clock and environment in plants provides a fitness advantage (Dodd et al. 2005) and in wheat several circadian clock genes are candidates for flowering time QTLs. In Arabidopsis a number of photosynthetic processes are under circadian control (Dodd, Kusakina, et al. 2014) and the major product of photosynthesis, sucrose, feeds back metabolic timing information to the circadian clock (Haydon, Mielczarek, et al. 2013). Quantification of circadian rhythms requires non-invasive measurement tools which are lacking in non-model organisms such as wheat. I therefore optimised a chlorophyll a fluorescence imaging system for the measurement of circadian rhythms in wheat. I then demonstrated that oscillations in wheat leaf temperature could be measured in continuous light and these oscillations were under circadian control. This led to the design of a low-cost leaf temperature measuring device based around an Arduino microcontroller which uses thermocouples directly attached to the surface of leaves to measure temperature. To determine the effect of the circadian clock on photosynthesis two tetraploid TILLING lines containing double null mutations of elf3 and gi were studied using a combination of chlorophyll a fluorescence, leaf temperature and time-course RT-qPCR. In both cases mutation of circadian clock genes caused a loss of rhythmic oscillations of circadian outputs in continuous conditions. Under diel conditions disruption of the circadian oscillator had little effect on photosynthesis but there were small effects on yield component traits. For the first time in wheat the effect of loss of functional GI on heading date was quantified. To date the effect of sugars on the wheat circadian oscillator have not been reported. Using a combination of RT-qPCR and chlorophyll a fluorescence I showed that the wheat orthologues of AtPRR7 and AtCCA1 respond differently to changes in sucrose levels compared to Arabidopsis. I showed that sucrose is required for the maintenance of wheat circadian oscillations in prolonged darkness. I also demonstrated the limitations of using chlorophyll a fluorescence for circadian phenotyping in darkness. |
| Exploitation Route | Of the general findings listed above the most important outcome of this project was the confirmation that orthologues of Arabidopsis circadian genes also function within the wheat circadian clock and they influence heading date. This should be of interest to plant breeders as it suggests that wheat circadian clock genes may provide novel targets for breeding. The development of a low cost direct contact leaf temperature measuring device may be of interest to those interested in phenotyping crops in controlled growth environments that don't have access to thermal imaging equipment. |
| Sectors | Agriculture, Food and Drink,Environment,Manufacturing, including Industrial Biotechology |
| Title | Non invasive measurement of circadian rhythms using temperature probes |
| Description | Circadian rhythms are 24 h oscillations. Non-invasive tools are required to measure circadian rhythms because the measurements can last over one week. We have developed an approach that allows non-invasive measure of circadian activity in plants by measuring changes in leaf temperature caused by rhythmic opening and closing of stomata. Changes in leaf temperate were measured using thermocouples attached to a leaf with data recording provided by Arduino boards. |
| Type Of Material | Technology assay or reagent |
| Year Produced | 2018 |
| Provided To Others? | No |
| Impact | We have been able to measure circadian rhythms in wheat mutants, allowing us to determine the nature of the circadian clock in wheat. |
| Description | BASF |
| Organisation | BASF |
| Country | Germany |
| Sector | Private |
| PI Contribution | Intellectual property, facilities and plant material |
| Collaborator Contribution | Intellectual property, expertise, bioinformatics, laboratory placements |
| Impact | Training of post graduate student in crop science and agribusiness approaches |
| Start Year | 2019 |
| Description | Participation in Science Sunday |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Public/other audiences |
| Results and Impact | The laboratory prepared an interactive display that described circadian rhythms for the Science Open Day. This usually attracts around 2000 people to the Plant Sciences display area. |
| Year(s) Of Engagement Activity | 2016 |