Characterization of Water Stress Related Transcriptome in Tall Fescue

Water stress is becoming a vital factor for tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] cultivation in the south-central USA. Genetic improvement of tall fescue for drought tolerance is the key strategy for improving persistence of tall fescue in the region. Genotypes with contrasting characteristics for relative water content and osmotic potential were identified from a tall fescue natural population. Transcriptome profiling between a drought tolerant (B400) and a susceptible (W279) genotype was carried out to unravel crucial genetic regulatory mechanism of water stress responses in tall fescue. Both the genotypes were evaluated under drought conditions. RNA samples from leaf, shoot, root, and inflorescence were sequenced through Illumina paired-end sequencing. The genotypes manifested differential transcriptional response under water stress condition. A total of 199,399 sequences were recovered with an average read length of 585 bp. Among 92,000 comparisons, 2,986 transcripts were differentially expressed between the two genotypes. Gene ontology (GO) and pathway analysis confirmed almost 2000 metabolic pathway and enzyme coding genes differentially expressed between the two. Almost 400 genes expressed differently related to phenylpropanoid biosynthesis confirmed the response variability of the two genotypes under water stress condition. This study will lead to identify genotype dependent gene in B400 responsible for drought tolerance and will also help to develop a comprehensive molecular marker system to facilitate marker-assisted breeding in tall fescue.