Mutational analysis of cell-specific gene expression in maize homeologous genes using a sorghum outgroup

Due to redundancy following a whole genome duplication, maize homeologous genes can evolve changes in the pattern of expression of one gene relative to its homeolog. In some cases these changes may be accompanied by deletion of a conserved noncoding sequence (CNS) from one of the two homeologs, a testable source of the change in expression (Freeling et al (2012) Curr. Opin. Plant Biol. 15:131-139). The most effective use of natural promoter bashing (fractionation mutagenesis) utilizes cell-specific transcriptosomes. In this project cell-specific expression of maize homeologous genes is compared, using sorghum as an outgroup to differentiate gain-of-expression from loss-of-expression.In the first set of experiments, fractionation mutagenesis is applied to two cell types undergoing tip growth, pollen and root hair, root hairs being defined as the difference in expression between root samples with and without root hairs. A third cell type, microspore, is also included.In the second set of experiments, fractionation mutagenesis is applied to another very specific developmental target, the cell/tissue-specific domains in the leaf primordia at the blade-sheath boundary that initiate ligule formation. Sorghum epidermal blade and ligule transcriptosome data supplement transcriptosome data already available in maize (Johnston et al. (2014) Plant Cell 26:4718-4732) (SRA project PRJNA287059).