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Browsing by Author "Gupta, Sarika"

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    2-Hydroxyacetophenone, the main component of the essential oil of the roots of Carissa opaca Stapf ex Haines
    (Taylor & Francis Group, 2009) Mallavarupu, Gopal R.; Mishra, Raghvendra K.; Chaudhary, Swati; Pandey, Richa; Gupta, Sarika; Kumar, Sushil
    The volatile oil obtained by hydrodistillation of the roots of Carissa opaca was analyzed by GC and GC/MS to study its composition. Thirty-five compounds representing 98.3% of the oil were identified. Si-gel chromatography of the oil yielded 2-hydroxyacetophenone, which was characterized by spectral methods (1H-, 13C-NMR and mass), as the main component, amounting to 89.5% of the oil.
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    Analysis of linalool content in the inflorescence (flower) essential oil and leaf oil of Lippia alba cultivar ‘Kavach’
    (Taylor & Francis Group, 2010) Mishra, Raghvendra K.; Chaudhary, Swati; Pandey, Richa; Gupta, Sarika; Mallavarapu, Gopal R.; Kumar, Sushil
    Lippia alba cultivar ‘Kavach’ is an aromatic, multi-branched, trailing, deep-rooted shrub that can be planted on slopes to control soil erosion. Cuttings of this genotype were planted on the edges of field plots developed by depositing agricultural soil on the rocky terrain of Aravalli mountain range land on which the Institute is located in New Delhi. Shoots harvested several times a year in the third, fourth and fifth year from planting were sampled for leaves and flowers bearing inflorescences to determine their biomass yield. The inflorescences and leaves sampled from the harvests of third year were analyzed by GC and GC/MS for their oil quality. Altogether 55 compounds were identified in leaf and inflorescence oils; a set of 47 compounds made up 96.3% of the leaf oil and 46 compounds made up 97.0% of inflorescence oil. The concentrations of linalool and 1,8-cineole were 67.7% and 6.4% in the leaf oil, whereas these were 79.3% and 5.2%, respectively, in inflorescence oil. The inflorescence oil also contained cis- and trans-linalool oxides (2.8%). The importance of the flower oil of L. alba cultivar ‘Kavach’ as a linalool-rich oil resource is discussed in terms of traditional sources of such oil and unique features of the cultivar.
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    Construction of genetic linkage map of the medicinal and ornamental plant Catharanthus roseus
    (Indian Academy of Sciences, 2007) Gupta, Sarika; Pandey-Rai, Sashi; Srivastava, Suchi; Naithani, Subhas Chandra; Prasad, Manoj; Kumar, Sushil
    An integrated genetic linkage map of the medicinal and ornamental plant Catharanthus roseus, based on different types of molecular and morphological markers was constructed, using a F2 population of 144 plants. The map defines 14 linkage groups (LGs) and consists of 131 marker loci, including 125 molecular DNA markers (76 RAPD, 3 RAPD combinations; 7 ISSR; 2 EST-SSR from Medicago truncatula and 37 other PCR based DNA markers), selected from a total of 472 primers or primer pairs, and six morphological markers (stem pigmentation, leaf lamina pigmentation and shape, leaf petiole and pod size, and petal colour). The total map length is 1131.9 cM (centiMorgans), giving an average map length and distance between two markers equal to 80.9 cM and 8.6 cM, respectively. The morphological markers/genes were found linked with nearest molecular or morphological markers at distances varying from 0.7 to 11.4 cM. Linkage was observed between the morphological markers concerned with lamina shape and petiole size of leaf on LG1 and leaf, stem and petiole pigmentation and pod size on LG8. This is the first genetic linkage map of C. roseus.
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    Development and utilization of novel intron length polymorphic markers in foxtail millet [Setaria italica (L.) P. Beauv.]
    (NRC Res Press, 2011) Gupta, Sarika; Kumari, Kajal; Das, Jyotirmoy; Lata, Charu; Puranik, Swati; Prasad, Manoj
    Introns are noncoding sequences in a gene that are transcribed to precursor mRNA but spliced out during mRNA maturation and are abundant in eukaryotic genomes. The availability of codominant molecular markers and saturated genetic linkage maps have been limited in foxtail millet (Setaria italica (L.) P. Beauv.). Here, we describe the development of 98 novel intron length polymorphic (ILP) markers in foxtail millet using sequence information of the model plant rice. A total of 575 nonredundant expressed sequence tag (EST) sequences were obtained, of which 327 and 248 unique sequences were from dehydration- and salinity-stressed suppression subtractive hybridization libraries, respectively. The BLAST analysis of 98 EST sequences suggests a nearly defined function for about 64% of them, and they were grouped into 11 different functional categories. All 98 ILP primer pairs showed a high level of cross-species amplification in two millets and two nonmil- lets species ranging from 90% to 100%, with a mean of ∼97%. The mean observed heterozygosity and Nei’s average gene diversity 0.016 and 0.171, respectively, established the efficiency of the ILP markers for distinguishing the foxtail millet accessions. Based on 26 ILP markers, a reasonable dendrogram of 45 foxtail millet accessions was constructed, demonstrating the utility of ILP markers in germplasm characterizations and genomic relationships in millets and nonmillets species.
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    Development and utilization of novel SSRs in foxtail millet [Setaria italica (L.) P. Beauv.]
    (John Wiley & Sons, 2013) Gupta, Sarika; Kumari, Kajal; Muthamilarasan, Mehanathan; Subramanian, Alagesan; Prasad, Manoj
    Although the foxtail millet [Setaria italica (L.) P. Beauv.] is recently regarded as a model crop for studying functional genomics of biofuel grasses, its genetic improvement to some extent was limited due to the non-availability of molecular markers, particularly the microsatellite markers and the saturated genetic linkage map. Considering this, we attempted to generate a significant number of microsatellite markers in cultivar ‘Prasad’. Two hundred and fifty-six clones were sequenced to generate 41.82-kb high-quality sequences retrieved from genomic library enriched with dinucleotide repeat motifs. Microsatellites were identified in 194 (76%) of the 256 positive clones, and 64 primer pairs (pp) were successfully designed from 95 (49%) unique SSR-containing clones. The 67.4% primer designing ability, 100% PCR amplification efficiency and 45.3% polymorphic potential in the parents of F2 mapping population established the efficacy of genomic microsatellites. All the 64 microsatellite markers displayed high level of cross-species amplification (~67%) in 10 millets and non-millets species. These experimental findings suggest the utility and efficacy of SSRs in diverse genotyping applications, resolving QTLs, phylogenetic relationships and transferability in several important grass species.
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    Development of eSSR-markers in Setaria italica and their applicability in studying genetic diversity, cross-transferability and comparative mapping in millet and non-millet species
    (PLOS, 2013) Kumari, Kajal; Muthamilarasan, Mehanathan; Misra, Gopal; Gupta, Sarika; Subramanian, Alagesan; Parida, Swarup K.; Chattopadhyay, Debasis; Prasad, Manoj
    Foxtail millet (Setariaitalica L.) is a tractable experimental model crop for studying functional genomics of millets and bioenergy grasses. But the limited availability of genomic resources, particularly expressed sequence-based genic markers is significantly impeding its genetic improvement. Considering this, we attempted to develop EST-derived-SSR (eSSR) markers and utilize them in germplasm characterization, cross-genera transferability and in silico comparative mapping. From 66,027 foxtail millet EST sequences 24,828 non-redundant ESTs were deduced, representing ~16 Mb, which revealed 534 (~2%) eSSRs in 495 SSR containing ESTs at a frequency of 1/30 kb. A total of 447 pp were successfully designed, of which 327 were mapped physically onto nine chromosomes. About 106 selected primer pairs representing the foxtail millet genome showed high-level of cross-genera amplification at an average of ~88% in eight millets and four non-millet species. Broad range of genetic diversity (0.02-0.65) obtained in constructed phylogenetic tree using 40 eSSR markers demonstrated its utility in germplasm characterizations and phylogenetics. Comparative mapping of physically mapped eSSR markers showed considerable proportion of sequence-based orthology and syntenic relationship between foxtail millet chromosomes and sorghum (~68%), maize (~61%) and rice (~42%) chromosomes. Synteny analysis of eSSRs of foxtail millet, rice, maize and sorghum suggested the nested chromosome fusion frequently observed in grass genomes. Thus, for the first time we had generated large-scale eSSR markers in foxtail millet and demonstrated their utility in germplasm characterization, transferability, phylogenetics and comparative mapping studies in millets and bioenergy grass species.
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    Foxtail millet: A model crop for genetic and genomic studies in bioenergy grasses
    (Informa UK Limited, an Informa Group Company (T&F Group), 2013) Lata, Charu; Gupta, Sarika; Prasad, Manoj
    Foxtail millet is one of the oldest domesticated diploid C4 Panicoid crops having a comparatively small genome size of approximately 515 Mb, short life cycle, and inbreeding nature. Its two species, Setaria italica (domesticated) and Setaria viridis (wild progenitor), have characteristics that classify them as excellent model systems to examine several aspects of architectural, evolutionary, and physiological importance in Panicoid grasses especially the biofuel crops such as switchgrass and napiergrass. Foxtail millet is a staple crop used extensively for food and fodder in parts of Asia and Africa. In its long history of cultivation, it has been adapted to arid and semi-arid areas of Asia, North Africa, South and North America. Foxtail millet has one of the largest collections of cultivated as well as wild-type germplasm rich with phenotypic variations and hence provides prospects for association mapping and allele-mining of elite and novel variants to be incorporated in crop improvement programs. Most of the foxtail millet accessions can be primarily abiotic stress tolerant particularly to drought and salinity, and therefore exploiting these agronomic traits can enhance its efficacy in marker-aided breeding as well as in genetic engineering for abiotic stress tolerance. In addition, the release of draft genome sequence of foxtail millet would be useful to the researchers worldwide in not only discerning the molecular basis of biomass production in biofuel crops and the methods to improve it, but also for the introgression of beneficial agronomically important characteristics in foxtail millet as well as in related Panicoid bioenergy grasses.
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    Genome-wide association study (GWAS) delineates genomic loci for ten nutritional elements in foxtail millet (Setaria italica L.)
    (Elsevier B.V., 2019) Jaiswal, Vandana; Bandyopadhyay, Tirthankar; Gahlaut, Vijay; Gupta, Sarika; Dhaka, Annvi; Ramchiary, Nirala; Prasad, Manoj
    Nutritional deficiency is found to be a major threat to human health, especially in low-income countries. Thus it is essential to improve nutritional qualities of important food crops. Foxtail millet is second largest cultivated millet and 2–5 times nutritionally richer than major cereal crops. During the present study, we identified genetic determinants of ten nutritional elements including potassium, nickel, calcium, boron, magnesium, phosphorus, sulphur, zinc, manganese and iron for the first time in foxtail millet. For this purpose, genome-wide association studies (GWAS) were conducted using 93 diverse accessions and 10 K SNPs (distributed across all the nine foxtail millet chromosomes). Altogether, 74 marker-trait associations (MTAs) were identified to be associated with above mentioned ten elements, out of which ten (10) MTAs (associated with B, Mg, Zn and Fe) showed high confidence [-log(p) > 5.78]. Identified desirable SNP alleles and favourable haplotypes may prove useful in foxtail breeding. Also, significant pyramiding effect suggested that associated elements can be substantially enhanced through combining more than one MTA. Candidate genes residing within or near the association signal may be selected for functional characterization. Superior genotypes identified may prove as a potential donor in foxtail millet breeding assisted through the molecular marker.
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    Genome-wide association study of major agronomic traits in foxtail millet (Setaria italica L.) using ddRAD sequencing
    (Springer Nature, 2019) Jaiswal, Vandana; Gupta, Sarika; Gahlaut, Vijay; Muthamilarasan, Mehanathan; Bandyopadhyay, Tirthankar; Ramchiary, Nirala; Prasad, Manoj
    Foxtail millet (Setaria italica), the second largest cultivated millet crop after pearl millet, is utilized for food and forage globally. Further, it is also considered as a model crop for studying agronomic, nutritional and biofuel traits. In the present study, a genome-wide association study (GWAS) was performed for ten important agronomic traits in 142 foxtail millet core eco-geographically diverse genotypes using 10 K SNPs developed through GBS-ddRAD approach. Number of SNPs on individual chromosome ranged from 844 (chromosome 5) to 2153 (chromosome 8) with an average SNP frequency of 25.9 per Mb. The pairwise linkage disequilibrium (LD) estimated using the squared-allele frequency correlations was found to decay rapidly with the genetic distance of 177 Kb. However, for individual chromosome, LD decay distance ranged from 76 Kb (chromosome 6) to 357 Kb (chromosome 4). GWAS identified 81 MTAs (marker-trait associations) for ten traits across the genome. High confidence MTAs for three important agronomic traits including FLW (flag leaf width), GY (grain yield) and TGW (thousand-grain weight) were identified. Significant pyramiding effect of identified MTAs further supplemented its importance in breeding programs. Desirable alleles and superior genotypes identified in the present study may prove valuable for foxtail millet improvement through marker-assisted selection.
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    Genome-wide development and use of microsatellite markers for large-scale genotyping applications in foxtail millet [Setaria italica (L.)]
    (Oxford University Press, 2013) Pandey, Garima; Misra, Gopal; Kumari, Kajal; Gupta, Sarika; Parida, Swarup K.; Chattopadhyay, Debasis; Prasad, Manoj
    The availability of well-validated informative co-dominant microsatellite markers and saturated genetic linkage map has been limited in foxtail millet (Setaria italica L.). In view of this, we conducted a genome-wide analysis and identified 28 342 microsatellite repeat-motifs spanning 405.3 Mb of foxtail millet genome. The trinucleotide repeats (∼48%) was prevalent when compared with dinucleotide repeats (∼46%). Of the 28 342 microsatellites, 21 294 (∼75%) primer pairs were successfully designed, and a total of 15 573 markers were physically mapped on 9 chromosomes of foxtail millet. About 159 markers were validated successfully in 8 accessions of Setaria sp. with ∼67% polymorphic potential. The high percentage (89.3%) of cross-genera transferability across millet and non-millet species with higher transferability percentage in bioenergy grasses (∼79%, Switchgrass and ∼93%, Pearl millet) signifies their importance in studying the bioenergy grasses. In silico comparative mapping of 15 573 foxtail millet microsatellite markers against the mapping data of sorghum (16.9%), maize (14.5%) and rice (6.4%) indicated syntenic relationships among the chromosomes of foxtail millet and target species. The results, thus, demonstrate the immense applicability of developed microsatellite markers in germplasm characterization, phylogenetics, construction of genetic linkage map for gene/quantitative trait loci discovery, comparative mapping in foxtail millet, including other millets and bioenergy grass species.
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    Identification of sex in Simmondsia chinensis (Jojoba) using RAPD markers
    (Springer, 2007) Agrawal, Veena; Sharma, Kuldeep; Gupta, Sarika; Kumar, Ravindra; Prasad, Manoj
    Simmondsia chinensis (Link) Schneider, a multipurpose dioecious shrub of arid zones, has emerged as a cash crop. It is being cultivated for its seeds which store liquid wax whose properties are similar to spermaceti (Sperm whale oil), a substitute for petro products and precious high-priced lubricants. Jojoba is a slow-growing desert shrub having a male biased (5:1; male:female ratio) population. Since there is no method available to determine the sex at the seedling stage, current investigations have been carried out to generate a sex-specific random amplified polymorphic DNA (RAPD) marker in jojoba which is based on the PCR amplification of random locations in the genome of plant. Of the 72 primers tested, only one random decamer primer, OPG-5, produced a unique *1,400 base pairs fragment in male DNA. To validate this observation, this primer was re-tested with the individuals of male and female samples of four cultivars. The unique *1,400 bp fragment was present in male individuals of all the four cultivars and completely absent in respective female individuals tested. To the best of our knowledge, this is the first report to ascertain the sex of jojoba plants at an early stage of development of the taxon.
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    ISSR marker assisted selection of male and female plants in a promising dioecious crop-Jojoba (Simmondsia chinensis)
    (Springer, 2008) Sharma, Kuldeep; Agrawal, Veena; Gupta, Sarika; Kumar, Ravindra; Prasad, Manoj
    Simmondsia chinensis (Link) Schneider, a multipurpose and monogeneric dioecious shrub from arid zones, has emerged as a cash crop all over the globe. Its seed propagation poses severe problems due to its male-biased population: the male:female ratio is 5:1. Investigations have been carried out to generate a sex-specific Inter-simple sequence repeat (ISSR) marker for the early detection of male and female plants. Of the 42 primers analysed with a bulk sample of pooled male DNA and a bulk sample of pooled female DNA, only one primer, UBC-807, produced a unique ~1,200 base-pair fragment in the male DNA. To validate this observation, this primer was re-tested with individual male and female samples from eight cultivars. A similar unique ~1,200 bp fragment was present in the male individuals of all eight cultivars and completely absent in the female individuals tested. This is the first report of the use of ISSR markers to ascertain sex in physiologically mature S. chinensis plants.
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    Molecular marker technology in plants
    (IK International Publishers, 2012) Gupta, Sarika; Ghose, Tapas Kumar; Jaiswal, J. P.; Prasad, Manoj
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    Novel intermolecular iterative mechanism for biosynthesis of mycoketide catalyzed by a bimodular polyketide synthase
    (PLOS, 2008) Chopra, Tarun; Banerjee, Srijita; Gupta, Sarika; Yadav, Gitanjali; Anand, Swadha; Surolia, Avadhesha; Roy, Rajendra P.; Mohanty, Debasisa; Gokhale, Rajesh S.
    In recent years, remarkable versatility of polyketide synthases (PKSs) has been recognized; both in terms of their structural and functional organization as well as their ability to produce compounds other than typical secondary metabolites. Multifunctional Type I PKSs catalyze the biosynthesis of polyketide products by either using the same active sites repetitively (iterative) or by using these catalytic domains only once (modular) during the entire biosynthetic process. The largest open reading frame in Mycobacterium tuberculosis, pks12, was recently proposed to be involved in the biosynthesis of mannosyl-b-1-phosphomycoketide (MPM). The PKS12 protein contains two complete sets of modules and has been suggested to synthesize mycoketide by five alternating condensations of methylmalonyl and malonyl units by using an iterative mode of catalysis. The bimodular iterative catalysis would require transfer of intermediate chains from acyl carrier protein domain of module 2 to ketosynthase domain of module 1. Such bimodular iterations during PKS biosynthesis have not been characterized and appear unlikely based on recent understanding of the three-dimensional organization of these proteins. Moreover, all known examples of iterative PKSs so far characterized involve unimodular iterations. Based on cell-free reconstitution of PKS12 enzymatic machinery, in this study, we provide the first evidence for a novel ‘‘modularly iterative’’ mechanism of biosynthesis. By combination of biochemical, computational, mutagenic, analytical ultracentrifugation and atomic force microscopy studies, we propose that PKS12 protein is organized as a large supramolecular assembly mediated through specific interactions between the C- and N-terminus linkers. PKS12 protein thus forms a modular assembly to perform repetitive condensations analogous to iterative proteins. This novel intermolecular iterative biosynthetic mechanism provides new perspective to our understanding of polyketide biosynthetic machinery and also suggests new ways to engineer polyketide metabolites. The characterization of novel molecular mechanisms involved in biosynthesis of mycobacterial virulent lipids has opened new avenues for drug discovery.
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    Population structure and association mapping of yield contributing agronomic traits in foxtail millet
    (Springer, 2014) Gupta, Sarika; Kumari, Kajal; Muthamilarasan, Mehanathan; Parida, Swarup K.; Prasad, Manoj
    Association analyses accounting for population structure and relative kinship identified eight SSR markers ( p < 0.01) showing significant association ( R (2) = 18 %) with nine agronomic traits in foxtail millet. Association mapping is an efficient tool for identifying genes regulating complex traits. Although association mapping using genomic simple sequence repeat (SSR) markers has been successfully demonstrated in many agronomically important crops, very few reports are available on marker-trait association analysis in foxtail millet. In the present study, 184 foxtail millet accessions from diverse geographical locations were genotyped using 50 SSR markers representing the nine chromosomes of foxtail millet. The genetic diversity within these accessions was examined using a genetic distance-based and a general model-based clustering method. The model-based analysis using 50 SSR markers identified an underlying population structure comprising five sub-populations which corresponded well with distance-based groupings. The phenotyping of plants was carried out in the field for three consecutive years for 20 yield contributing agronomic traits. The linkage disequilibrium analysis considering population structure and relative kinship identified eight SSR markers (p < 0.01) on different chromosomes showing significant association (R (2) = 18 %) with nine agronomic traits. Four of these markers were associated with multiple traits. The integration of genetic and physical map information of eight SSR markers with their functional annotation revealed strong association of two markers encoding for phospholipid acyltransferase and ubiquitin carboxyl-terminal hydrolase located on the same chromosome (5) with flag leaf width and grain yield, respectively. Our findings on association mapping is the first report on Indian foxtail millet germplasm and this could be effectively applied in foxtail millet breeding to further uncover marker-trait associations with a large number of markers.
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    Sequence based novel genomic microsatellite markers for robust genotyping purposes in foxtail millet [Setaria italica (L.) P. Beauv.]
    (Springer Science, 2012) Gupta, Sarika; Kumari, Kajal; Sahu, Pranav Pankaj; Vidapu, Sudhakar; Prasad, Manoj
    The unavailability of microsatellite markers and saturated genetic linkage map has restricted the genetic improvement of foxtail millet [Setaria italica (L.) P. Beauv.], despite the fact that in recent times it has been documented as a new model species for biofuel grasses. With the objective to generate a good number of microsatellite markers in foxtail millet cultivar 'Prasad', 690 clones were sequenced which generated 112.95 kb high quality sequences obtained from three genomic libraries each enriched with different microsatellite repeat motifs. Microsatellites were identified in 512 (74.2%) of the 690 positive clones and 172 primer pairs (pp) were successfully designed from 249 (48.6%) unique SSR-containing clones. The efficacies of the microsatellite containing genomic sequences were established by superior primer designing ability (69%), PCR amplification efficiency (85.5%) and polymorphic potential (52%) in the parents of F(2) mapping population. Out of 172 pp, functional 147 markers showed high level of cross-species amplification (~74%) in six grass species. Higher polymorphism rate and broad range of genetic diversity (0.30-0.69 averaging 0.58) obtained in constructed phylogenetic tree using 52 microsatellite markers, demonstrated the utility of markers in germplasm characterizations. In silico comparative mapping of 147 foxtail millet microsatellite containing sequences against the mapping data of sorghum (~18%), maize (~16%) and rice (~5%) indicated the presence of orthologous sequences of the foxtail millet in the respective species. The result thus demonstrates the applicability of microsatellite markers in various genotyping applications, determining phylogenetic relationships and comparative mapping in several important grass species.
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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.
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    Variability in Indian bread wheat (Triticum aestivum L.) varieties differing in nitrogen efficiency as assessed by microsatellite markers
    (Springer, 2010) Chandna, Ruby; Gupta, Sarika; Ahmad, Altaf; Iqbal, Muhammad; Prasad, Manoj
    Wheat (Triticum aestivum L.) is a staple food for half of the world. Its productivity and agronomical practices, especially for nitrogen supplementation, is governed by the nitrogen efficiency (NE) of the genotypes. We analyzed 16 popular cultivated Indian varieties of wheat for their NE and variability estimates using a set of 21 simple sequence repeat (SSR) markers, derived from each wheat chromosome. These genotypes were categorized into three groups, viz., low, moderate, and high nitrogen efficient. Of these 16 genotypes, we have reported six, eight, and two genotypes in high, moderate, and low NE categories, respectively. The differential NE in these genotypes was supported by nitrogen uptake and assimilation parameters. The values of average polymorphic information content and marker index for these SSR markers were estimated to be 0.32 and 0.59, respectively. The genetic similarity coefficient for all possible pairs of varieties ranged from 0.41 to 0.76, indicating the presence of considerable range of genetic diversity at molecular level. The dendrogram prepared on the basis of unweighted pair-group method of arithmetic average algorithm grouped the 16 wheat varieties into three major clusters. The clustering was strongly supported by high bootstrap values. The distribution of the varieties in different clusters and subclusters appeared to be related to their variability in NE parameter that was scored. Genetically diverse parents were identified that could potentially be used for their desirable characteristics in breeding programs for improvement of NE in wheat.

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