From Agronomy and Ecophysiology to Molecular Genetics for Improving Nitrogen Use Efficiency in Crops
Titel:
From Agronomy and Ecophysiology to Molecular Genetics for Improving Nitrogen Use Efficiency in Crops
Auteur:
Hirel, Bertrand Lemaire, Gilles
Verschenen in:
Journal of crop improvement
Paginering:
Jaargang 15 (2006) nr. 2 pagina's 213-257
Jaar:
2006-06-16
Inhoud:
Improved nitrogen use efficiency (NUE: capacity to produce a supplement of yield for each added unit of N fertilizer) has the potential to enhance yield under low nitrogen (N) and thereby improve crop nutritional quality while reducing ground water contamination by nitrates. In order to realize potential benefits with respect to sustainable agriculture, we need to identify the physiological, biochemical and molecular mechanisms controlling component processes, including inorganic N uptake, N reduction, N partitioning between roots and shoots and N-incorporation into organic molecules as a function of carbon availability. Moreover, sustained decreases in fertilizer input and improved or stabilized yield require an improved understanding of the transition between N assimilation and N remobilization during plant development. Recent advances in plant molecular biotechnology, combined with modern physiological and biochemical studies, have expanded our understanding of the regulatory mechanisms controlling the primary steps of inorganic N assimilation and the subsequent biochemical pathways involved in N supply for secondary metabolism. In parallel, a number of physiological and agronomic studies have been undertaken to identify which are the limiting steps in the control of N uptake, assimilation and recycling during plant growth and development. Although they have been very informative in defining key elements of the economy of N, our knowledge of the regulation of N acquisition and management is still fragmentary. This is partly because most biochemical and molecular studies were designed to identify the key physiological and morphological traits involved, but were rarely placed in a whole plant or an agronomic context. To help fill the gap that still exists between molecular and agronomic studies, we describe in this chapter how the understanding of the control of N assimilation has increased through the use of whole plant physiology, transgenic technology, quantitative genetics and agronomic approaches. In addition, one of the goals of this review is to obtain a more integrated view of the regulation of N management from the gene to the field within the plant or within a particular organ. Prospects for future development and applications in crop improvement are explored.
Tijdschrift beschrijving