title: Transcriptome analysis reveals season-specific rbcS gene expression profiles in diploid perennial ryegrass (Lolium perenne L.).
abstract: Perennial ryegrass (Lolium perenne L.) is a major grass species used for forage and turf throughout the world, and gains by conventional breeding have reached a plateau. Perennial ryegrass is an outcrossing, self-incompatible diploid (2n = 2x = 14) with a relatively large genome (4067 Mbp/diploid genome; Evans, G.M., Rees, H., Snell, C.L. and Sun, S. (1972) The relation between nuclear DNA amount and the duration of the mitotic cycle. Chrom. Today, 3, 24-31). Using tissues sourced from active pastures during the peak of the autumn, winter, spring and summer seasons, we analysed the ryegrass transcriptome employing a Serial Analysis of Gene Expression (SAGE) protocol, with the dual goals of understanding the seasonal changes in perennial ryegrass gene expression and enhancing our ability to select genes for genetic manipulation. A total of 159,002 14-mer SAGE tags was sequenced and mapped to the perennial ryegrass DNA database, comprising methyl-filtered (GeneThresher) and expressed sequence tag (EST) sequences. The analysis of 14,559 unique SAGE tags, which were present more than once in our SAGE library, revealed 964, 1331, 346 and 131 exclusive transcripts to autumn, winter, spring and summer, respectively. Intriguingly, our analysis of the SAGE tags revealed season-specific expression profiles for the small subunit of ribulose-1,5-bisphosphate carboxylase (Rubisco), LprbcS. The transcript level for LprbcS was highest in spring, and then decreased gradually between summer and winter. Five different copies of LprbcS were revealed in ryegrass, with one possibly producing splice variant transcripts. Two highly expressed LprbcS genes were reported, one of which was not active in autumn. Another LprbcS gene showed an inverse expression profile to the autumn inactive LprbcS in a manner to compensate the expression level.
authors.affiliation: Pastoral Genomics, c/o ViaLactia Biosciences (NZ) Ltd, PO Box 109185, Newmarket, Auckland 1149, New Zealand. sathish.puthigae@vialactia.com
authors.forename: Puthigae
authors.initials: P
authors.lastname: Sathish
authors.forename: Nimali
authors.initials: N
authors.lastname: Withana
authors.forename: Margaret
authors.initials: M
authors.lastname: Biswas
authors.forename: Catherine
authors.initials: C
authors.lastname: Bryant
authors.forename: Kerry
authors.initials: K
authors.lastname: Templeton
authors.forename: Muhannad
authors.initials: M
authors.lastname: Al-Wahb
authors.forename: Claudia
authors.initials: C
authors.lastname: Smith-Espinoza
authors.forename: John R
authors.initials: JR
authors.lastname: Roche
authors.forename: Kieran M
authors.initials: KM
authors.lastname: Elborough
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Phillips
mesh_terms: D017398:Alternative Splicing; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D014644:Genetic Variation; D018745:Genome, Plant; D008129:Lolium / Q000166:cytology / Q000201:enzymology / Q000235:genetics*; D008938:Mitosis; D030821:Plants, Genetically Modified / Q000201:enzymology; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics*; D012621:Seasons; D014158:Transcription, Genetic
chemical_list: D012273:Ribulose-Bisphosphate Carboxylase