title: Simple sequence repeats in organellar genomes of rice: frequency and distribution in genic and intergenic regions.
abstract: BACKGROUND
  Simple sequence repeats (SSRs) are abundant across genomes. However, the significance of SSRs in organellar genomes of rice has not been completely understood. The availability of organellar genome sequences allows us to understand the organization of SSRs in their genic and intergenic regions.
  
  
  RESULTS
  We have analyzed SSRs in mitochondrial and chloroplast genomes of rice. We identified 2528 SSRs in the mitochondrial genome and average 870 SSRs in the chloroplast genomes. About 8.7% of the mitochondrial and 27.5% of the chloroplast SSRs were observed in the genic region. Dinucleotides were the most abundant repeats in genic and intergenic regions of the mitochondrial genome while mononucleotides were predominant in the chloroplast genomes. The rps and nad gene clusters of mitochondria had the maximum repeats, while the rpo and ndh gene clusters of chloroplast had the maximum repeats. We identified SSRs in both organellar genomes and validated in different cultivars and species.
authors.affiliation: Biotechnology Laboratory, Crop Improvement Section, Directorate of Rice Research Rajendranagar, Hyderabad-500030, India.
authors.forename: Passoupathy
authors.initials: P
authors.lastname: Rajendrakumar
authors.forename: Akshaya Kumar
authors.initials: AK
authors.lastname: Biswal
authors.forename: Sena M
authors.initials: SM
authors.lastname: Balachandran
authors.forename: Kommoju
authors.initials: K
authors.lastname: Srinivasarao
authors.forename: Raman M
authors.initials: RM
authors.lastname: Sundaram
mesh_terms: D001483:Base Sequence; D002736:Chloroplasts / Q000737:chemistry / Q000235:genetics*; D018742:DNA, Chloroplast / Q000032:analysis*; D021901:DNA, Intergenic / Q000032:analysis*; D018900:Dinucleotide Repeats; D005787:Gene Frequency; D005819:Genetic Markers; D018598:Minisatellite Repeats; D008928:Mitochondria / Q000737:chemistry / Q000235:genetics*; D012275:Oryza / Q000235:genetics*; D018515:Plant Leaves / Q000737:chemistry
chemical_list: D018742:DNA, Chloroplast; D021901:DNA, Intergenic; D005819:Genetic Markers