Track 4-1-4: Biotechnological Approaches to Improve Range, Pasture and Forage Species

Description

Apomixis is an asexual reproduction through seeds where embryo develops without meiosis and fertilization. It is widely distributed throughout plant kingdom, but is more prevalent in families like Asteraceae, Rosaceae and Poaceae (Carman, 1997). This trait is highly desirable for fixing heterosis in F1 hybrids with significant implications for crop improvement (Dwivedi et al., 2007). Therefore it is necessary to unravel the molecular and genetic basis of apomixis to tap its potential. Pennisetum is an important genus of the Poaceae family which contains a wide range of species exhibiting wide variability in morphological, molecular, and reproductive traits (Jauhar, 1998). It includes many apomictic wild relatives of cultivated pearl millet (Pennisetum glaucum), some of them used extensively for introgression and molecular studies on apomixis, such as P. squamulatum, P. ciliare, and P. orientale (Ozias-Akins and Van Dijk, 2007; Kaushal et al., 2010). In order to identify putative genes involved in expression of apomixis, the genes showing differential expression across sexual and apomictic genotypes may be identified and characterized. A variety of methods are available for such molecular differential screening. These include differential display, fingerprinting techniques like cDNA AFLP, Subtractive hybridization, Micro array and Gene Chip technologies. These methods are employed for different purposes based on their convenience, sensitivity, automation and throughput. Texa with contrasting modes of reproduction are resources to identify genes involved in apomixis phenomenon. Broadly, the differentiation in reproduction pathway between apomictic and sexual lines is at three steps viz. pre-meiotic (including genes involved in preparing of ovule to enter into apomeiotic pathway), meiotic (genes involved in apomeiosis and embryo-sac development) and post-meiotic (genes involved in embryo-sac maturation and preparing for parthenogenesis). The present study was aimed to carry out a comprehensive transcriptome survey to identify differentially expressed transcripts in ovules of aposporous Pennisetum hybrid during the pre-meiotic stage of apomictic reproduction.

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Transcriptome Analysis of Differentially Expressed Genes at Pre-Meiotic Developmental Stage in Pennisetum Hybrids with Contrasting Modes of Reproduction

Apomixis is an asexual reproduction through seeds where embryo develops without meiosis and fertilization. It is widely distributed throughout plant kingdom, but is more prevalent in families like Asteraceae, Rosaceae and Poaceae (Carman, 1997). This trait is highly desirable for fixing heterosis in F1 hybrids with significant implications for crop improvement (Dwivedi et al., 2007). Therefore it is necessary to unravel the molecular and genetic basis of apomixis to tap its potential. Pennisetum is an important genus of the Poaceae family which contains a wide range of species exhibiting wide variability in morphological, molecular, and reproductive traits (Jauhar, 1998). It includes many apomictic wild relatives of cultivated pearl millet (Pennisetum glaucum), some of them used extensively for introgression and molecular studies on apomixis, such as P. squamulatum, P. ciliare, and P. orientale (Ozias-Akins and Van Dijk, 2007; Kaushal et al., 2010). In order to identify putative genes involved in expression of apomixis, the genes showing differential expression across sexual and apomictic genotypes may be identified and characterized. A variety of methods are available for such molecular differential screening. These include differential display, fingerprinting techniques like cDNA AFLP, Subtractive hybridization, Micro array and Gene Chip technologies. These methods are employed for different purposes based on their convenience, sensitivity, automation and throughput. Texa with contrasting modes of reproduction are resources to identify genes involved in apomixis phenomenon. Broadly, the differentiation in reproduction pathway between apomictic and sexual lines is at three steps viz. pre-meiotic (including genes involved in preparing of ovule to enter into apomeiotic pathway), meiotic (genes involved in apomeiosis and embryo-sac development) and post-meiotic (genes involved in embryo-sac maturation and preparing for parthenogenesis). The present study was aimed to carry out a comprehensive transcriptome survey to identify differentially expressed transcripts in ovules of aposporous Pennisetum hybrid during the pre-meiotic stage of apomictic reproduction.