Abstract
More than 80% of land plants, including most crops, establish symbiosis with Arbuscular mycorrhizal (AM) fungi to improve nutrient acquisition from soil. Hyphae of AM fungi form appressoria on the root surface, penetrate the epidermis, grow inter- and intracellularly, and form arbuscules in root cortical cells. External hyphae extend into the soil, absorb phosphate and other nutrients, and then supply the host plants with the nutrients via arbuscules in exchange for plant photosynthates. Arbuscules and plant cytoplasm are separated by plant plasma membrane-derived periarbuscular membrane (PAM). The plant cells are thought to take up the nutrients using transporters or channels on PAM. However, the transporters have been poorly characterized.
We focused our attention on inorganic nutrient transporters involved in mycorrhizal symbiosis of soybean. Genome sequence data indicate that the soybean genome contains a number of presumed transporter genes. We examined their expression patterns and tried to identify mycorrhiza-inducible transporter genes.