Identification of genes involved in the floral transition at the shoot apical meristem of Lolium perenne L. by use of suppression subtractive hybridisation

Generally, heading in Lolium perenne L. (perennial ryegrass) is associated with a reduction in the feed quality of the forage and therefore extending the period of vegetative growth during the growing season will contribute to an improvement in quality. The genetic control of floral transition has been well studied in model plant species but less research has been done in economically important crop species such as perennial ryegrass. A differential gene expression study was performed between two full sibling lines of L. perenne with contrasting flowering time. Suppression subtractive hybridization was used to identify 155 transcripts differentially expressed between the two sibling lines in the shoot apical meristem after primary and during secondary induction. Transcripts with a putative role in the floral transition were further characterized, through floral induction stages, by real time RT-PCR. This revealed five genes with greater than tenfold difference in expression between the lines during floral induction. Furthermore, a putative methyl binding domain protein and bHLH transcription factor were identified, which show clear differential expression patterns through floral induction and may act as potential enhancers of flowering in L. perenne.