Robert W. Holley Center for Agriculture and Health, USDA-ARS and Department of Plant Biology, Cornell University, USA
Aluminum (Al) toxicity is a major limiting factor both for food and bioenergy crops on acid soils that comprise up to 50% of the world’s potentially arable lands. A large proportion of the acid soils occur in developing countries in the tropics and subtropics where food and energy security are the most tenuous. Also, there is a significant area of acid soils in the Southeastern U.S., which may be a useful region for the production of bioenergy sorghum. Because of the agronomic importance of crop Al toxicity, identifying the molecular determinants for Al tolerance has attracted significant interest from a number of laboratories around the world. We are now poised, based on recent discoveries by our labs and others, to develop the molecular and genetic resources required to address a worldwide agronomic problem that is only exceeded by drought stress with regards to abiotic limitations to bioenergy and food crop production.
In this talk, the isolation of the major sorghum Al tolerance gene, SbMATE, via high-resolution mapping has opened up new avenues for improving cereal acid soil tolerance. The role of this gene in controlling the wide range of Al tolerance in sorghum via regulation of SbMATE function and expression will be described. The combination of genetics, genomics and protein biochemistry has shown us that other molecular determinants reside in the sorghum genome that help regulate both SbMATE expression and SbMATE protein function, resulting in greater levels of Al tolerance. This research is allowing us to assemble a molecular toolbox that is being used to translate these discoveries into more Al tolerant sorghum lines for production on acid soils both in Brazil and in developing countries in sub-Saharan Africa.