Centre for Agriculture, Food and Environmental Management (CAFEM). Knocking-down Vacuolar Nitrate Accumulation in Duckweeds


  • Qualification type: PhD
  • Subject area: Genetics, Plant Biotechnology, Molecular Biology
  • Location/Campus: University of Hertfordshire, College Lane Campus
  • Start date: Spring 2024, exact date TBC
  • Closing application date: 30 April 2024
  • Duration: Full time (three years)

Project outline

The urgent need for sustainable protein sources to address global food security is the only ground-breaking response, especially with the environmental crisis driven by the Western world's demand for soy, leading to widespread deforestation (less than 15% of the annual soy import in the UK is certified as “deforestation free”). Duckweeds (Lemnaceae) have emerged as a promising alternative crop, offering a sustainable protein source for animal feed. This "golden era" for duckweeds has seen the rise of industrial projects by biotech companies, tapping into the potential of this fast-growing aquatic plant. Duckweeds possess remarkable potential, yielding up to 30 tons per hectare annually with a protein content exceeding 40% in dry biomass. However, nitrate accumulation poses significant challenges, impacting nitrogen use efficiency and posing health risks to humans and animals. Our recent studies have shown nitrate levels in duckweeds surpassing regulatory limits, potentially hindering their commercialisation.

To address this issue, our PhD project aims to engineer genome-edited duckweeds to reduce vacuolar nitrate accumulation and maximize protein conversion. Building on our team's research, we will focus on characterizing vacuolar LemnaCLCa nitrate transporters and selectively knocking down LemnaCLCa genes. This approach is expected to decrease nitrate accumulation and enhance nitrogen use efficiency (NUE) by redirecting carbon flux towards protein synthesis. Strengthening our expertise in in-vitro genetic transformation and CRISPR-Cas9 genome editing, we will implement these strategies. Chemical analysis using our developed FTIR -Spectroscopy methods will facilitate the quantification of nitrate and protein in duckweed biomass. Additionally, we will expand our spectroscopic techniques with Raman microscopy to visualize nitrate distribution within cells.

Success in this venture would not only enhance protein production in duckweeds but also pave the way for genetically engineered leafy vegetables, addressing regulatory concerns related to nitrate accumulation. By achieving both goals simultaneously, our project holds immense potential to revolutionize sustainable protein production and mitigate environmental and health risks associated with nitrate accumulation. Join us in this ground breaking research to shape the future of agriculture and food sustainability!


Entry requirements

Applicants must have a BSc qualification (First-Class Honours or Upper Second-Class Honours) or equivalent in a relevant field. A MSc/MRes qualification is also desirable.


  • Please note that the studentship is available exclusively to applicants who are permanent UK residents and qualify for home fees status. The University particularly welcomes applications from British Black, Asian and Minority Ethnic applicants.

How to apply

Applicants are required to provide the following documents:

  • A completed application form
  • A cover letter explaining their interest in and the relevance of their background to the proposed project
  • An up-to-date CV
  • Two academic references. You should arrange for your referees to send their reference via email directly to the Doctoral College.
  • Copies of qualification certificates and transcripts.

Your completed application should be emailed to the Doctoral College.

For informal enquires please email: Dr Cristina Barrero Sicilia

Interviews will take place shortly after the closing date.

Funding information

The studentship is offered on a full-time basis from spring 2024 for three years (subject to satisfactory progress) and provides a Tax free stipend (currently £18,622 per annum for 2023-24) and a fee waiver for the PhD for a period of three years.