Transcriptome Analysis of Differentially Expressed Genes During Embryo Sac Development in Apomeiotic Non-Parthenogenetic Interspecific Hybrid of Pennisetum glaucum

• Published in: Molecular biotechnology 2012-07, Vol.51 (3), p.262-271
• Main Authors: Sahu, Pranav Pankaj, Gupta, Sarika, Malaviya, D. R, Roy, Ajoy Kumar, Kaushal, Pankaj, Prasad, Manoj
• Format: Article
• Language: English
• Subjects: Apomixis; Apomixis - genetics; Biochemistry; Biological and medical sciences; Biological Techniques; Biotechnology; Brachiaria brizantha; Cell Biology; Cellular biology; Chemistry; Chemistry and Materials Science; chromosome 2; Chromosome Mapping; Cluster Analysis; Computer Simulation; Data processing; embryo sac; embryogenesis; Embryos; Fertilization; flowering; Fundamental and applied biological sciences. Psychology; Gametogenesis; Gene expression; Gene Expression Profiling - methods; gene expression regulation; Gene mapping; genes; Genes, Plant - genetics; genotype; Genotype & phenotype; Genotypes; Human Genetics; Hybridization; Hybrids; loci; megasporocytes; Oryza - genetics; Oryza - metabolism; Oryza sativa; ova; Ovule - genetics; Ovule - metabolism; ovules; Parthenogenesis; Paspalum notatum; Pennisetum - genetics; Pennisetum - metabolism; Pennisetum glaucum; Plant Proteins - biosynthesis; Plant Proteins - genetics; Plant reproduction; Pollen; Polymerase chain reaction; progeny; protein metabolism; Protein Science; Protein turnover; quantitative polymerase chain reaction; rice; Seeds - genetics; Seeds - metabolism; Sequence Homology, Nucleic Acid; sexual development; Stress; stress response; suppression subtractive hybridization; Synteny; Transcription; transcription (genetics); transcriptomics; Translation; Urochloa brizantha
• ISSN: 1073-6085; 1559-0305
• DOI: 10.1007/s12033-011-9464-9

Apomixis results in the production of genetically uniform progeny, derived from the fertilization independent development (parthenogenesis) of an unreduced egg cell (apomeiosis). To identify genes involved in the apomeiosis, a comparative transcriptome analysis of differentially expressed genes during embryo sac (ES) development in a sexual Pennisetum glaucum (genotype 81A1) and its apomeiotic (aposporic) non-parthenogenetic interspecific hybrid (BC1GO) was investigated. BC1GO exhibited the partitioned apomeiosis component, whereby the second apomixis component viz., parthenogenesis was completely lacking. A total of 96 non-redundant transcripts were recovered using suppression subtractive hybridization and classified into 11 different categories according to their putative functions. Amongst the identified transcripts, many of them belonged to unknown function (40%) followed by those involved in protein metabolism, stress response, pollen/ovule/embryo development, and translation/protein modification process. A data search of transcriptional profiling in other apomictic species revealed that 75% of the differentially expressed transcripts have not been reported in previous studies. By macroarray analysis, we identified differential expression pattern of 96 transcripts, 45 (47%) of which showed ≥2-fold induction in apomeiotic BC1GO. Further, the obtained results were validated by quantitative real-time polymerase chain reaction to have a comparative expression profiling of eight selected up-regulated transcripts (≥2.5-fold) between BC1GO and 81A1 at different phases of ovule development. In silico mapping demonstrated that 13 transcripts were located onto rice chromosome 2, region syntenic with the apospory locus as reported in Brachiaria brizantha and Paspalum notatum. The expression patterns of these transcripts showed a significant difference at differentiating megaspore mother cell and gametogenesis stages thereby suggesting their involvement in floral development during apomeiotic (Panicum-type aposporous) ES development.