Evolution of Potential Energy Grass Genome Structure
The Saccharinae group of grasses contains two members that are potentially important sources of sugar and lignocellulosic biomass for bioenergy, due at least in part to highly efficient C4 photosynthesis. These grasses are the warm temperate-tropical sugarcane (Saccharum officinarum) and Miscanthus spp., which can yield high levels of biomass at temperate latitudes. A close relative is sorghum (Sorghum bicolor), also grown as a bioenergy feedstock in addition to its use as food and feed. In contrast to sorghum, the Saccharinae grasses are known for polyploidy and possess high chromosome numbers, offering an opportunity to investigate the evolutionary processes of genome duplication, genome structure, and the implications for crop improvement strategies. Researchers funded by the joint U.S. Department of Agriculture-Department of Energy Plant Feedstock Genomics for Bioenergy program have applied genome sequencing and global comparative analyses of Miscanthus, Saccharum, and sorghum to gain insight into the different evolutionary fates of Miscanthus and Saccharum after they diverged from sorghum. The researchers report evidence for the existence of a genome duplication shared between Saccharum and Miscanthus as well as an additional Saccharum-specific duplication event. Understanding the genome structure of these two complex grasses in relation to the closely related and fully sequenced sorghum genome will facilitate breeding efforts to improve bioenergy-relevant traits such as biomass yield and adaptation to changing environments.
Kim, C., X. Wang, T.-H. Lee, K. Jakob, G.-J. Lee, and A. H. Paterson. 2014. “Comparative Analysis of Miscanthus and Saccharum Reveals a Shared Whole-Genome Duplication but Different Evolutionary Fates,” Plant Cell 26, 2420-29. DOI:10.1105/tpc.114.125583.