The first step in engineering nitrogen fixing cereals; transferring the capability to perceive rhizobial bacteria (sLOLA)

Lead Research Organisation: John Innes Centre
Department Name: Contracts Office

Abstract

The evolution of nodulation in legumes has involved the recruitment of a pre-exisiting signalling pathway, the symbiosis signalling pathway, to allow the recognition of rhizobial bacteria. The symbiosis signalling pathway is present in most species of plants and functions in the establishment of the mycorrhizal symbiosis. Cereals possess the symbiosis signalling pathway and it has been shown that the components of this pathway in cereals function in a manner analogous to their orthologs in legumes during nodulation signalling. The signalling molecules produced by rhizobial bacteria, so called Nod factors, are very similar to Myc factors produced by mycorrhizal fungi and recent work shows that non-legumes can perceive these lipo-chito oligosaccharide signals to activate the symbiosis signalling pathway.Thus there are close parallels between the mechanisms of recognition of mycorrhizal fungi in many plant species, including cereals, and the recognition of rhizobial bacteria by legumes. This means that it is feasible to engineer cereals to allow the recognition of rhizobial bacteria as a symbiont, with potential consequences for the accommodation of these nitrogen-fixing bacteria. This proposal is a partner to an international programme of research currently under consideration by The Bill and Melinda Gates Foundation. The two proposals build on the knowledge gleaned from years of research in nodulation signalling in legumes to engineer cereals for recognition of rhizobial bacteria and the initiation of nodule organogenesis. These two proposals provide the scale of investment necessary to begin a major new strategic initiative to engineer nitrogen-fixing cereals. This is an ambitious goal and one that cannot be achieved within a 5 year timeframe. However, it is anticipated that some level of fixed nitrogen in cereals could be achieved along the route to a fully functioning nitrogen-fixing nodule on a cereal root, with implications for sustainable food production.

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