Legume research – symbiotic nitrogen fixation and food sustainability
Presented by Peter M. Gresshoff
Centre of Integrative Legume Research (CILR), SAFS, University of Queensland.
Tuesday 3 March 15, 1.00 – 2.00 pm
Room 275, GCI Building (# 20)
There are over 18,000 legume species on this earth. We eat a few of them (peanuts, beans, peas, lentils); our farm animals use them as fodder (clovers, medics) or direct feed (soybean). Some are trees (wattle, black bean) and provide timber or biofuel (Pongamia).
Most legumes have the ability to enter two important symbioses; a) with common soil fungal species resulting in mycorrhizae capable of mobilising phosphorus from soil and b) with natural soil bacteria (broadly called ‘rhizobium’) capable of symbiotic nitrogen fixation. Nitrogen (N) is the limiting element for crop production. Although abundant in the atmosphere, dinitrogen (N2) gas is very stable; plants and animals cannot use it. Bacteria such as ‘rhizobium’, however, have the enzymes complexes (like nitrogenase) to convert N2 to ammonium (NH4 +). Ammonium is the building block for all amino acid and related biosynthesis. Rhizobium also has genes that trigger new cell divisions in root cortex of legumes to develop a new organ, the nodule, necessary for nitrogen fixation to occur efficiently. Thus infected (nodulated) legumes do not need supplemental (costly and polluting) N fertiliser (industrially produced by the Haber-Bosch Process).
Worldwide research is progressing with its analysis of the nodulation and nitrogen fixation process. Key genes have been discovered, and orthologues have been demonstrated in non-legumes. The presentation will deal with the current state of research (including that at UQ) and will emphasise the strategic importance of using legume food species capable of overcoming some of the limitations and costs seen with other food sources.
Peter Gresshoff is a plant developmental geneticist, using molecular and genetic tools to understand complexities of gene networks during the control of nodule formation in legumes. He obtained a BSc. in Biochemistry and Genetics from the University of Alberta (1970), a PhD. in Plant Somatic Cell Genetics from the Australian National University (1973), and a DSc. for Nodulation Genetics from ANU (1989).
He was appointed as endowed Racheff Chair of Excellence for Plant Molecular Genetics in 1988 at the University of Tennessee Knoxville, then (1999) Head of Botany, The University of Queensland. Since 2003, he is Director of the Centre for Integrative Legume Research (CILR) at UQ. He was awarded twice the German Alexander von Humboldt Fellowship.
For further information, contact convenor Jane O’Sullivan (email@example.com )