On the path to better millet crops

Phosphorus is one of the limiting nutrients in agriculture, with productivity of up to 40 % of the world's arable land affected by low phosphorus levels. Engineering staple crops such as foxtail millet (Setaria italica) to better absorb and use phosphorus is therefore a priority for improved food security.

The EU-funded 'Improved millets for phosphate acquisition and transport' (IMPACT) project undertook to improve phosphorus uptake and transport by better understanding the proteins involved in this process. Specifically, researchers investigated a family of phosphorus transporter proteins called Pht1.

They studied the growth rate, phosphate levels and chlorophyll production of foxtail millet plants over a broad range of phosphorus concentrations. From the findings, IMPACT determined concentrations that represented phosphorus deficiency and phosphorus repletion in foxtail millet.

Using these conditions, researchers studied the expression of 12 different Pht1 proteins in leaves, shoots and roots of phosphorus-replete and -deficient plants. They found one protein that is always expressed and two that are induced by phosphorus deficiency (one in the leaves and one in the roots).

Other project work involved the use of bioinformatics to better understand how these proteins are regulated or controlled in foxtail millet. Researchers also spent some time creating artificial gene expression systems to simplify detailed studies of Pht1 proteins.

IMPACT established a foundation for further study of phosphorus metabolism in foxtail millet and contributed to our understanding of how crop plants use phosphorus. This may have a far-reaching impact on crop yield and global food security.