Browsing by Author "Roy, Ajoy Kumar"

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    Development, characterization and cross-species transferability of genomic SSR markers in berseem (Trifolium alexandrinum L.), an important multi-cut annual forage legume
    (Springer, 2015) Verma, Priyanka; Chandra, Amaresh; Roy, Ajoy Kumar; Malaviya, Devendra Ram; Kaushal, Pankaj; Pandey, Dinesh; Bhatia, Sabhyata
    Egyptian clover (Trifolium alexandrinum), a multi-cut forage legume, is widely grown as an annual feed crop. Genetic improvement in this legume is largely hampered due to limited availability of genomic resources. Hence, a genomic library enriched for GA/CT motif was constructed to develop SSR primers. As a result, 667 SSR primer pairs were developed and 111 were validated in T. alexandrinum cv. Wardan s-99-1. Among these, 45 primer pairs were used for the analysis of genetic diversity among 86 Trifolium accessions, resulting in 220 alleles with an average of 4.88 alleles per locus. Polymorphic information content for these markers ranged from 0.040 to 0.819 with an average of 0.445. The observed and expected heterozygosity for individual loci ranged from 0.39 to 0.89 and 0.368 to 0.80 with an average of 0.675 and 0.659, respectively. The markers exhibited varied levels of cross-species transferability ranging from 93.33 % across T. resupinatum to 40.0 % across T. balansae. Phylogenetic relationships were analyzed using the unweighted pair group method with arithmetic averages (UPGMA)-based dendrogram which was able to establish the uniqueness of each genotype and grouped them into two major clusters. To the best of our knowledge, the SSR markers reported here are among the first to be reported in this important yet neglected forage legume. They were assessed to be highly efficient and polymorphic and found to be useful for distinguishing the closely related genotypes of Trifolium. This large resource of SSR markers would therefore facilitate new avenues for T. alexandrinum genomics.
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    Transcriptome analysis of differentially expressed genes during embryosac development in apomeiotic non parthenogenetic interspecific hybrid of Pennisetum glaucum
    (Springer, 2012) Sahu, Pranav Pankaj; Gupta, Sarika; Malaviya, D. R.; Roy, Ajoy Kumar; Kaushal, Pankaj; Prasad, Manoj
    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.