• Allan Downie's Research

• Ray Dixon

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Curriculum Vitae

• 1971 BSc University of Strathclyde
• 1974 PhD University of Dundee
• 1975 Postdoctoral Fellow. Radiation biology and Biophysics, University of Rochester, New York
• 1976 Research Fellow; John Curtin School of Medical Research, Australian National University
• 1981 Project Leader, John Innes Institute
• 1985 Project Leader, CSIRO Division of Plant Industry, Canberra Australia
• 1988-present Project leader John Innes Centre
• 1999-present Honorary Professor, University of East Anglia, UK
• 2006-present Chair of Faculty
• 2006-present Member of Central Management Board John Innes Centre

Allan Downie

Emeritus Fellow

Molecular Microbiology

Contact details

allan.downie@jic.ac.uk

Research interests

Rhizobium attachment to and infection of legume roots

Symbiotic nitrogen fixation on legume roots requires the attachment of rhizobia to roots and root hairs. This is required for the induction of nodule morphogenesis and the root infection events that lead to the infection of the root nodules in which the bacteria fix nitrogen and make it available to the plants. My group is investigating the role and interplay between (a) quorum-sensing (population-density-dependent) regulation of gene expression, (b) surface polysaccharides and (c) secreted proteins, during surface attachment of Rhizobium leguminosarum biovar viciae, focussing on attachment to root hairs.  

Calcium signalling in legume roots during nodulation

Rhizobia attached to root hairs produce nodulation (Nod) factors that induce a calcium influx at the tip of legume root hairs and then calcium oscillations (called calcium spiking) around the nuclear region of these cells. In collaboration with Giles Oldroyd we are analysing how the perception of Nod-factors is coupled to the induction of early nodulation genes in legumes. This has involved identification of legume nodulation genes some of which are required for induction of the calcium signals whereas others integrate the calcium signals leading to gene expression.