After nearly a decade of efforts, RIKEN scientists have identified the structure of a key carrier protein that helps wheat and barley plants capture iron from the soil. Approximately one-third of all the world's land is alkaline because the soil contains large amounts of alkaline salt, calcium carbonate. Iron is poorly soluble in alkaline soils, and the resulting deficiency of this element seriously limits the growth of many cultivated plants.

"However, wheat and barley have developed a unique strategy of capturing iron. They secrete compounds called phytosiderophores. When they reach the ground, they bind to iron and form a complex that plants can absorb through their roots," says Atsushi Yamagata of RIKEN Biosystems' Center for Dynamic Research.

"Phytosiderophores are compounds known as mumic acids. Carrying their iron load, they are reabsorbed into plant cells by a carrier protein in cell membranes. Previously, there were many unknowns in the molecular mechanism of this process. Now, for the first time, we have been able to determine the structure of the carrier protein. We revealed the structure of the carrier protein, both in the free state and in combination with an iron-containing phytohydrophore. It's very important," he adds.

The RIKEN team has been trying to determine the structure of the carrier protein for nearly a decade. "We didn't even get the crystals needed for X-ray crystallography analysis," the researcher continues. The breakthrough came with recent advances in the technique of cryoelectron microscopy, which revealed structures firing electrons in frozen protein samples. We are currently focused on the development of mygic acid derivatives, which can become a new generation of highly effective fertilizers for alkaline soils.

A synthetic derivative, developed by our colleague Kosuke Namba at Tokushima University, can improve plant growth better than a natural compound for just one-thousandth the cost. A derivative called proline-2'-deoxymugic acid (PDMA) is stable for a month in the soil, compared to a day for a natural connection. Negotiations are underway to expand PDMA production for commercial use as agricultural fertilizer."

Source: Agrolink