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  The evolution of extreme nitrogen uptake in plants


   Department of Biosciences

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  Dr G Chomicki, Prof S Paterson, Prof K Lindsey  No more applications being accepted  Competition Funded PhD Project (European/UK Students Only)

About the Project

Background: The speed at which plants can take up nitrogen is a key limitation to plant growth rate. Genetic engineering to increase nitrogen use efficiency has met limited success because plants can modify their nitrogen uptake efficiency mechanisms in function of the available nitrogen level. Recently, a farming symbiosis involving ants that cultivate, fertilize, live in and defend epiphytic plants (Squamellaria) has been discovered in the Fiji Islands. In this symbiosis, farming ants have practised a form of ‘precision agriculture’ for millions of years, wherein they actively and exclusively provide nitrogen-rich faeces on particular plant structures called warts, which have evolved an extreme nitrogen uptake rate. This project aims to decipher how these symbiotic plants have this extreme uptake efficiency despite high nitrogen concentration.

Aims and Methodology: The student will conduct gene expression and comparative genomic analyses to identify candidate genes linked to nitrogen uptake in Squamellaria. Physiological assays will be used to determine the kinetics of nitrogen absorption in vivo, using greenhouse-cultivated plants. Immunolocalisation and tools to transiently down-regulate gene expression will be used to target candidate genes. Reverse genetics will be used to test the effect of Squamellaria nitrogen transporters in Arabidopsis both under their native as well as root-specific promoters.

Timetable: Year 1: Complete transcriptomic and genomic analyses and start physiological assays; clone nitrogen transporters from Squamellaria. Year 2: Perform transient gene editing assays in Squamellaria, finish physiological assays and transform constructs with Squamellaria nitrogen transporters in Arabidopsis. Year 3: Perform nitrogen fertilization growth assays to compare growth rate and yield of the different transgenic lines and write up thesis.

HOW TO APPLY

Applications should be made by emailing [Email Address Removed] with a CV (including contact details of at least two academic (or other relevant) referees), and a covering letter – including whatever additional information you feel is pertinent to your application; you may wish to indicate, for example, why you are particularly interested in the selected project and at the selected University. Applications not meeting these criteria will be rejected.

In addition to the CV and covering letter, please email a completed copy of the Additional Details Form (Word document) to [Email Address Removed]. A blank copy of this form can be found at: https://www.nld-dtp.org.uk/how-apply.

Informal enquiries may be made to [Email Address Removed]

Please note that the closing date for applications is Monday 18th May at 12noon.

Funding Notes

This is a 4 year BBSRC studentship under the Newcastle-Liverpool-Durham DTP. The successful applicant will receive research costs, tuition fees and stipend (£15,009 for 2019-20). The PhD will start in October 2020. Applicants should have, or be expecting to receive, a 2.1 Hons degree (or equivalent) in a relevant subject. EU candidates must have been resident in the UK for 3 years in order to receive full support. Please note, there are 2 stages to the application process.

References

1. (2016). Obligate plant farming by a specialized ant. Nature Plants 2: 16181.

2. (2017). Partner abundance controls mutualism stability and the pace of morphological change over geologic time. Proceedings of the National Academy of Sciences of the U.S.A. 114: 3951-3956.

3. (2019). Farming by ants remodels nutrient uptake in epiphytes. New Phytologist 223: 2011-2023.

4. (2016). Partner choice through concealed floral sugar rewards evolved with the specialization of ant–plant mutualisms. New Phytologist 211: 1358-1370.

5. (2010). Antagonistic coevolution accelerates molecular evolution. Nature 464: 275-278.

6. (2015). The Fasciola hepatica genome: gene duplication and polymorphism reveals adaptation to the host environment and the capacity for rapid evolution. Genome Biology 16: 71.

7. (2018). Increased socially mediated plasticity in gene expression accompanies rapid adaptive evolution. Ecology Letters 21: 546-556.

8. (2006). The POLARIS peptide of Arabidopsis regulates auxin transport and root growth via effects on ethylene signaling. The Plant Cell 18: 3058-3072.

9. (2016). Abscisic acid regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin. New Phytologist 211: 225-239.

10. (2017). Asymmetric subgenome selection and cis-regulatory divergence during cotton domestication. Nature Genetics 49: 579-587.