BBSRC CASE PhD Studentship with TARRC

PhD project title:

Increasing latex yield in the rubber tree Hevea brasilensis by targeted expression of aquaporins


Principal Supervisor: Dr Lorenzo Frigerio, School of Life Sciences
Industrial supervisor: Dr Alessandra Di Cola, Tun Abdul Razak Research Centre (TARRC)

Start date: October 2012 (duration: 4 years)

Application deadline: 27 April 2012

Project description:

This project will combine the academic supervisor’s expertise in the cell biology of plant aquaporins with the leading expertise in rubber plant genomics and transformation technology of the industrial partner, TARRC. The project aims at translating basic cell biology information into increased yield of natural rubber.

Natural rubber (NR) is a polymer of global importance. Current rubber production is insufficient to meet the worldwide demand for this product. There are economic concerns that global supplies of NR will shrink as a consequence of climate change, therefore there is an urgent need for strategies aimed at increasing NR yield.

Latex flow during tapping of the rubber plant Hevea brasilensis is the crucial parameter for rubber yield. The extent of latex flow depends on water circulation in the tissues surrounding the latex-producing cells. Water, and therefore latex flow, can be stimulated by ethylene or auxin treatment of the bark. It has recently been shown that water flow depends on two aquaporins (AQP, proteins acting as water channels), which are expressed in those tissues. Ethylene leads to the upregulation of these AQP1. It appears that these AQP can also be stimulated by other treatments, such as auxin, and the traditionally used sulphur and copper. Thus the modulation of AQP expression (by chemical treatment) directly affects latex flow and NR yield.

At Warwick we have recently characterised the expression and localisation of the Arabidopsis tonoplast intrinsic protein family of AQP and dissected their exquisite tissue-specificity2-4. As the AQP family is conserved in higher plants, two of the Arabidopsis AQP we characterised are highly similar to the Hevea AQP isoforms so far identified. We will exploit this equivalence to manipulate AQP expression levels in the relevant tissues of Hevea, in order to provide high latex flow in response to tapping, but without the need for chemical treatments.

The student will join the bioinformatics team at TARRC and perform an extensive study of the newly-sequenced Hevea genome to identify and classify all Hevea AQP. Sh/e will then use organ-specific transcriptomic data obtained at TARRC to identify the AQP isoforms that are expressed in the appropriate organs. At the same time the student will search for promoter sequences associated to genes whose expression is upregulated in the tissues surrounding the latex-producing cells. At Warwick, having identified the best candidate genes and promoters, the student will engineer genetic constructs for the expression of the Hevea AQP and of cognate Arabidopsis AQP in native form or as fluorescent protein fusions under constitutive, tissue-specific, or wound-inducible promoters. The native promoters will also be modified to become unresponsive to ethylene/auxin. The constructs will be first introduced and characterised in transgenic Arabidopsis plants and tested for subcellular localisation, tissue-specificity, overall expression levels and stability. This will require a combination of biochemistry and live confocal microscopy. This analysis will lead to the identification of the most promising constructs, which will then be introduced into the Hevea elite clone PB260 at TARRC. AQP expression will be tested in young seedlings and latex-producing cells (laticifers) produced in cultured callus5.

This project will constitute the first, essential step in a novel breeding programme to produce Hevea plants with the capacity to generate high latex flow rates upon tapping in the absence of chemical treatments.

References

(1) Tungngoen K et al. (2009) Plant Physiol 151: 843-56.

(2) Gattolin S et al. (2011) Mol Plant 4: 180-9.

(3) Gattolin S et al. (2009) BMC Plant Biol 9: 133.

(4) Hunter PR et al. (2007) Plant Physiol. 145: 1371-1382.

(5) Tan D et al. (2011) Plant Cell Rep 30: 1117-24.

Key experimental skills involved:

The project will provide a unique multidisciplinary training opportunity for a PhD student, who will learn bioinformatics, molecular biology, cell biology, bioimaging, plant transformation and a wide range of transferable skills, both within the academic and industrial settings.

Eligibility

In brief, candidates are required to satisfy two principal eligibility conditions (Residence and Qualification)

Residence

  • British nationals who have lived in the UK all their lives are eligible.

  • Also eligible are non-British nationals who have settled status AND have been resident in the UK for 3 years immediately prior to the date of the start of the course.

  • EU nationals who have been ordinarily resident in the UK and Islands for three years immediately prior to the date of start of the course;

  • EU nationals not resident in the UK are eligible for a fees-only award. In the event of receiving such an award, you would have to make separate arrangements to defray the costs of accommodation and subsistence.

  • EEA and Swiss nationals (EEA migrant workers) should refer to the full guidelines to check eligibility

Academic requirement

  • Those who have a 1st or a 2.1 undergraduate degree in a relevant field are eligible.
  • Those who have a 2.2 and an additional Masters degree in a relevant field may be eligible.
  • Those who have a 2.2 and at least three years post-graduate experience in a relevant field may be eligible.
  • Those with degrees abroad (as well as, perhaps, postgraduate experience) may be eligible if their qualifications are deemed equivalent to any of the above


Funding

  • A stipend equivalent to UK Research Councils (at least £13,590 per annum) will be paid plus provisionally a stipend top up from the Industrial partner (£2,500 per annum)
  • Tuition fees at the UK/EU level will be covered

Contact details for application enquiries:
Dr Lorenzo Frigerio
School of Life Sciences
University of Warwick
tel 02476 523181
email l.frigerio@warwick.ac.uk
web http://www2.warwick.ac.uk/fac/sci/lifesci/people/lfrigerio/

How to apply

Keywords: plant, secretory pathway , cell biology, aquaporins, tonoplast, imaging, GFP, natural rubber, Hevea, biotechnology

Contact details for application enquiries:

Dr Lorenzo Frigerio
School of Life Sciences
University of Warwick
tel 02476 523181
email l.frigerio@warwick.ac.uk
web http://www2.warwick.ac.uk/fac/sci/lifesci/people/lfrigerio/

How to apply