Understanding Mineral Transport in Switchgrass for Enhanced Sustainability
A viable bioenergy industry will depend on the development of sustainably grown feedstocks, which are bioenergy crops that yield high amounts of biomass with minimal inputs of water, fertilizer, and other chemicals. The efficient acquisition and mobilization of mineral nutrients by feedstocks are key to their sustainability. Additionally, the platform used to produce biofuel from plant feedstocks (e.g., pyrolysis and thermochemical) is affected by biomass minerals (e.g., high levels of silicon in ash decreases conversion efficiency). In perennial bioenergy plants such switchgrass, certain minerals are recycled—mobilized from senescing tissues in the autumn to perennial crowns, rhizomes, and roots for winter storage, and remobilized and translocated to growing stem and leaf tissues in the spring. This seasonal storage and recycling of minerals depends on specific transporters for movement into and out of cells, a poorly understood process. With funding from the joint U.S. Department of Agriculture-Department of Energy Plant Feedstocks Genomics for Bioenergy activity, researchers combined bioinformatics and real-time qRT-PCR approaches to classify mineral transporter genes and gene families in switchgrass and to discern differential expression of these genes during the growing season. In this first molecular study of mineral transporter genes in switchgrass, 520 genes in 40 different families were identified and both tissue and temporal specificity of expression was observed. These results provide the foundation for correlating expression of specific genes with mineral translocation. This will facilitate functional characterization of genes critical for efficient nutrient transport and use and will lead to the development of sustainable, high-yielding switchgrass cultivars.
Palmer, N. A., A. J. Saathoff, B. M. Waters, T. Donze, T. M. Heng-Moss, P. Twigg, C. M. Tobias, and G. Sarath. 2014. “Global Changes in Mineral Transporters in Tetraploid Switchgrasses (Panicum virgatum L.),” Frontiers in Plant Science 4, DOI: 10.3389/fpls.2013.00549.