Gene mutagenesis systems and resources for the saccharinae

This chapter focuses on mutant populations in Saccharinae that are available for genomic studies. Emphasis is on sorghum mutant resources as few mutant resources are available in sugarcane or Miscanthus due to polyploidy of their genomes. As a minimally redundant genome that last experienced genome duplication 70 million years ago, sorghum is particularly sensitive to ethyl methane sulfonate (EMS) and other mutagens, with many mutagenized lines displaying various phenotypes at EMS concentrations as low as 0.1%. Many mutant phenotypes have the potential to increase biomass production or bioenergy conversion efficiency of sorghum plants. Characterizing these sorghum mutants may also provide useful information to improve biomass production and bioenergy conversion efficiency or other traits of other plants, for example via RNAi technology. The small size of the sorghum genome, its diploid nature, and high gene density also make sorghum an obvious choice for an efficient transposon tagging system. The Candystripe1 (Cs1) transposon has been isolated. The activity of Cs1 has been demonstrated in the y1 locus, and several mutations have been isolated. An understanding of the genetic behavior of this element has been gathered toward the development of a viable transposon tagging system in sorghum.