Expression analysis of rbcS genes by RT-PCR in oat species with different ploidy levels

ABSTRACT

The genomic organization and expression of the rbcS gene family were studied in oat species having different ploidy levels in order not only to analyze the divergence among them but also to investigate the phenomenon of diploidization following interspecific hybridization. RFLP analyses of genomic DNAs suggested that rbcS genes in oat belong to a small multigenic family and are present with a similar copy number in polyploid and diploid species with an interspecific length polymorphism. The same qualitative and quantitative pattern was obtained in the Northern analysis of all the species with the exception of the autotetraploid A. vaviloviana which presents a very faint hybridization signal, as if chromosome doubling had interfered negatively with gene expression. To improve the resolution power in detecting interspecific differences among similar transcripts we used the combined RT-PCR and RFLP technique. Fragments, obtained by amplifying total RNA using primers from conserved regions of rbcS genes, had similar lengths in all the species examined, but a different restriction pattern was observed in the tetraploid A. maroccana when the PCR fragments were digested.