Physiological and molecular mechanisms and adaptation strategies in soybean (Glycine max) under phosphate deficiency

Abstract

Phosphorus is a major plant macronutrient involved in many and different biological processes, such as energy transfer (ATP), photosynthesis, respiration, biosynthesis of nucleic acids and proteins, membrane biosynthesis (e.g., phospholipids), and signaling pathways. Legumes, including soybean, are highly dependent on the availability of scarcely available organic phosphorus in the rhizosphere, especially when considering the need for phosphorous during nodulation-a legume-specific mutualistic symbiotic interaction between plants and nitrogen-fixing soil bacteria. As a consequence, the limited assimilation of phosphorus greatly hinders the nodulation process, soybean growth and soybean yield. Thus, understanding how soybean responds to low-phosphorus situations is imperative for breeding towards low-phosphorus tolerance. Toward these aims, scientists are using powerful genetic and molecular technologies to identify soybean genes playing essential roles in plant resistance to low-phosphorus environments. Functional genomic studies on soybean, as well as on other legumes suitable for comparative genomic with soybean, have provided valuable information in recent years and hold bright promise for the future. In this chapter, taking advantage of the recent development of high-throughput sequencing technologies, the sequencing of the soybean genome, the development a various biotechnological and breeding platforms, and the molecular, cellular and physiological analyses of soybean response to phosphate (Pi) deprivation, we describe our current understanding of the adaptation of soybean plants to limited Pi availability.