Phytic Acid Biosynthesis and Transport in Phaseolus vulgaris: Exploitation of New Genomic Resources

Although common bean has a good content in essential minerals, it also accumulates significant amounts of compounds that reduce its nutritional value by lowering nutrient bioavailability. Phytic acid, which is the major form of phosphorus stored in the seed, is one of such compounds, as, during gastro-intestinal passage, it binds trace elements and reduces their absorption, leading, under certain dietary circumstances, to mineral (mostly Fe, Zn, Ca) deficiencies. A major goal for grain crop improvement is the reduction of phytic acid content in the seed to improve micronutrient bioavailability, through the identification of low phytic acid (lpa) mutants. In common bean only one of such mutants has been described so far. Genes involved in phytic acid pathway and transport have been described in different species, including common bean. Recently, new genomic resources have become available for the common bean research community, thanks to the release of two whole genome sequences: the Andean G19833 and the Mesoamerican BAT93 genotypes. In this chapter we use the two common bean reference genomes to compare the sequences of genes involved or putatively involved in phytic acid synthesis and transport, some of them never reported in this species. Moreover, we discuss transcriptomic data of these genes, reported in different organs at different developmental stages for the Mesoamerican genotype. Finally, we discuss alternatives on how to exploit these new genomic resources to study and eventually manipulate phytic acid pathway and transport.