Genomic and genetic control of phosphate stress in legumes

Authors: Gebeyaw, Mesfin; LIU, JUNQI - UNIVERSITY OF MINNESOTA; ALLAN, DEBORAH - UNIVERSITY OF MINNESOTA; Vance, Carroll

Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2007
Publication Date: 6/4/2007
Citation: Gebeyaw, M.T., Liu, J., Allan, D.L., Vance, C.P. 2007. Genomic and genetic control of phosphate stress in legumes. Plant Physiology. 144:594-603.

Interpretive Summary: Legume crops such as soybeans, alfalfa, peas, and dry beans are important for their high nutritional value for humans and animals. Legumes provide about 33% of the human's dietary protein needs, as well as 35-40% of the world's cooking oil needs. Legume crops are also important for their contribution to making agricultural production more sustainable. They can make their own nitrogen fertilizer through a process called symbiotic nitrogen fixation and do not need chemical sources of nitrogen fertilizer. Phosphorus (P) is one of the most important plant nutrients required for legume growth. There are environmental and economic problems associated with the use of P fertilizers in agriculture. In the developed world, farms are fertilized with excess P resulting in the contamination of surface waters. By comparison, in the developing nations, adequate P is unavailable for crop cultivation. Recent advances in plant genetics and genomics methods in legumes have provided greater opportunities for progress to be made on P-deficiency stress in plants. As a result, our understanding of the genetic and molecular aspects of P metabolism in plants is improving. More importantly, we need to translate our research findings at the fundamental level to legume improvement for the well being of humankind through food security and less reliance on non-renewable resources and plant fertilizer use. In this report we document the discovery of genes and adaptive mechanisms that allow plants to obtain soil P more efficiently. Utilizing these genes to improve P acquisition and use would be extremely beneficial for sustainable crop agriculture.

Technical Abstract: Phosphorus (P) is critical for plant growth and development, particularly for N2-fixing legumes due to the high demand for P in root nodules. Genomic and molecular studies of P-stress in legumes have used a variety of research strategies and have focused primarily on white lupin, common bean, soybean, and Medicago. A large number of genes and proteins with potential roles in P-stress tolerance have been identified in legumes and major themes in the molecular control of P-stress response have been established. Emerging areas of research include the control of transcription and microRNA-mediated signaling in P-stress in plants; the putative interplay between sugars, photosynthate and P-stress sensing; transcription factors that mediate root development under P-stress; and the role phytohormones play in modulating plant adaptation to P-stress. Microarrays have been in the forefront as powerful research tools for generating large amounts of data for parallel gene expression analysis. As seen in the recent cloning and characterizing of the genes that define P-stress signaling in plants, microarrays and the availability of several plant mutants have opened up research possibilities to elucidate the genetic and molecular control of P-stress response in plants. Indeed, it would seem that the next few years promise to bring a burst of fundamental new discoveries regarding mechanisms and regulation of P-stress tolerance in plants. Research tools such as RNAi-based gene silencing strategies would aid efforts to design and evaluate gene function with the ultimate aim of identifying candidate genes for improving the tolerance and adaptation of P-stress in plants.