Browsing by Author "Pradhan, Seema"

Now showing 1 - 6 of 6

Dissecting the root nodule transcriptome of chickpea (Cicer arietinum L.)
(PLOS, 2016) Kant, Chandra; Pradhan, Seema; Bhatia, Sabhyata
A hallmark trait of chickpea (Cicer arietinum L.), like other legumes, is the capability to convert atmospheric nitrogen (N2) into ammonia (NH3) in symbiotic association with Mesorhizobium ciceri. However, the complexity of molecular networks associated with the dynamics of nodule development in chickpea need to be analyzed in depth. Hence, in order to gain insights into the chickpea nodule development, the transcriptomes of nodules at early, middle and late stages of development were sequenced using the Roche 454 platform. This generated 490.84 Mb sequence data comprising 1,360,251 reads which were assembled into 83,405 unigenes. Transcripts were annotated using Gene Ontology (GO), Cluster of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways analysis. Differential expression analysis revealed that a total of 3760 transcripts were differentially expressed in at least one of three stages, whereas 935, 117 and 2707 transcripts were found to be differentially expressed in the early, middle and late stages of nodule development respectively. MapMan analysis revealed enrichment of metabolic pathways such as transport, protein synthesis, signaling and carbohydrate metabolism during root nodulation. Transcription factors were predicted and analyzed for their differential expression during nodule development. Putative nodule specific transcripts were identified and enriched for GO categories using BiNGO which revealed many categories to be enriched during nodule development, including transcription regulators and transporters. Further, the assembled transcriptome was also used to mine for genic SSR markers. In conclusion, this study will help in enriching the transcriptomic resources implicated in understanding of root nodulation events in chickpea.
Genome-wide analysis of the CCCH zinc finger family identifies tissue specific and stress responsive candidates in chickpea (Cicer arietinum L.)
(PLOS, 2017) Pradhan, Seema; Kant, Chandra; Verma, Subodh; Bhatia, Sabhyata
The CCCH zinc finger is a group of proteins characterised by a typical motif consisting of three cysteine residues and one histidine residue. These proteins have been reported to play important roles in regulation of plant growth, developmental processes and environmental responses. In the present study, genome wide analysis of the CCCH zinc finger gene family was carried out in the available chickpea genome. Various bioinformatics tools were employed to predict 58 CCCH zinc finger genes in chickpea (designated CarC3H1-58), which were analysed for their physio-chemical properties. Phylogenetic analysis classified the proteins into 12 groups in which members of a particular group had similar structural organization. Further, the numbers as well as the types of CCCH motifs present in the CarC3H proteins were compared with those from Arabidopsis and Medicago truncatula. Synteny analysis revealed valuable information regarding the evolution of this gene family. Tandem and segmental duplication events were identified and their Ka/Ks values revealed that the CarC3H gene family in chickpea had undergone purifying selection. Digital, as well as real time qRT-PCR expression analysis was performed which helped in identification of several CarC3H members that expressed preferentially in specific chickpea tissues as well as during abiotic stresses (desiccation, cold, salinity). Moreover, molecular characterization of an important member CarC3H45 was carried out. This study provides comprehensive genomic information about the important CCCH zinc finger gene family in chickpea. The identified tissue specific and abiotic stress specific CCCH genes could be potential candidates for further characterization to delineate their functional roles in development and stress.
Global transcriptome analysis of developing chickpea (Cicer arietinum L.) seeds
(Frontiers Media S.A., 2014) Pradhan, Seema; Bandhiwal, Nitesh; Shah, Niraj; Kant, Chandra; Gaur, Rashmi; Bhatia, Sabhyata
Understanding developmental processes, especially in non-model crop plants, is extremely important in order to unravel unique mechanisms regulating development. Chickpea (C. arietinum L.) seeds are especially valued for their high carbohydrate and protein content. Therefore, in order to elucidate the mechanisms underlying seed development in chickpea, deep sequencing of transcriptomes from four developmental stages was undertaken. In this study, next generation sequencing platform was utilized to sequence the transcriptome of four distinct stages of seed development in chickpea. About 1.3 million reads were generated which were assembled into 51,099 unigenes by merging the de novo and reference assemblies. Functional annotation of the unigenes was carried out using the Uniprot, COG and KEGG databases. RPKM based digital expression analysis revealed specific gene activities at different stages of development which was validated using Real time PCR analysis. More than 90% of the unigenes were found to be expressed in at least one of the four seed tissues. DEGseq was used to determine differentially expressing genes which revealed that only 6.75% of the unigenes were differentially expressed at various stages. Homology based comparison revealed 17.5% of the unigenes to be putatively seed specific. Transcription factors were predicted based on HMM profiles built using TF sequences from five legume plants and analyzed for their differential expression during progression of seed development. Expression analysis of genes involved in biosynthesis of important secondary metabolites suggested that chickpea seeds can serve as a good source of antioxidants. Since transcriptomes are a valuable source of molecular markers like simple sequence repeats (SSRs), about 12,000 SSRs were mined in chickpea seed transcriptome and few of them were validated. In conclusion, this study will serve as a valuable resource for improved chickpea breeding.
High density linkage mapping of genomic and transcriptomic SNPs for synteny analysis and anchoring the genome sequence of chickpea
(Nature Publishing Group, 2015) Gaur, Rashmi; Jeena, Ganga; Shah, Niraj; Gupta, Shefali; Pradhan, Seema; Tyagi, Akhilesh K.; Jain, Mukesh; Chattopadhyay, Debasis; Bhatia, Sabhyata
This study presents genome-wide discovery of SNPs through next generation sequencing of the genome of Cicer reticulatum. Mapping of the C. reticulatum sequenced reads onto the draft genome assembly of C. arietinum (desi chickpea) resulted in identification of 842,104 genomic SNPs which were utilized along with an additional 36,446 genic SNPs identified from transcriptome sequences of the aforementioned varieties. Two new chickpea Oligo Pool All (OPAs) each having 3,072 SNPs were designed and utilized for SNP genotyping of 129 Recombinant Inbred Lines (RILs). Using Illumina GoldenGate Technology genotyping data of 5,041 SNPs were generated and combined with the 1,673 marker data from previously published studies, to generate a high resolution linkage map. The map comprised of 6698 markers distributed on eight linkage groups spanning 1083.93 cM with an average inter-marker distance of 0.16 cM. Utility of the present map was demonstrated for improving the anchoring of the earlier reported draft genome sequence of desi chickpea by ~30% and that of kabuli chickpea by 18%. The genetic map reported in this study represents the most dense linkage map of chickpea , with the potential to facilitate efficient anchoring of the draft genome sequences of desi as well as kabuli chickpea varieties.
A high-density SNP-based linkage map using genotyping-by-sequencing and its utilization for improved genome assembly of chickpea (Cicer arietinum L.)
(Springer Nature Publishing AG, 2020) Gaur, Rashmi; Verma, Subodh; Pradhan, Seema; Ambreen, Heena; Bhatia, Sabhyata
Genotyping-by-sequencing (GBS) allows rapid identification of markers for use in development of linkage maps, which expedite efficient breeding programs. In the present study, we have utilized GBS approach to identify and genotype single-nucleotide polymorphism (SNP) markers in an inter-specific RIL population of Cicer arietinum L. X C. reticulatum. A total of 141,639 raw SNPs were identified using the TASSEL-GBS pipeline. After stringent filtering, 8208 candidate SNPs were identified of which ~ 37% were localized in the intragenic regions followed by genic regions (~ 30%) and intergenic regions (~ 27%). We then utilized 6920 stringent selected SNPs from present study and 6714 SNPs and microsatellite markers available from previous studies for construction of linkage map. The resulting high-density linkage map comprising of eight linkage groups contained 13,590 markers which spanned 1299.14 cM of map length with an average marker density of 0.095 cM. Further, the derived linkage map was used to improve the available assembly of desi chickpea genome by anchoring 443 previously unplaced scaffolds onto eight linkage groups. The present efforts have refined anchoring of the desi chickpea genome assembly to 55.57% of the ~ 520 Mb of assembled desi genome. To the best of our knowledge, the linkage map generated in the present study represents one of the most dense linkage map developed for the crop till date. It will serve as a valuable resource for fine mapping and positional cloning of important quantitative trait loci (QTLs) associated with agronomical traits and also for anchoring and ordering of future genome sequence assemblies.
Identification and molecular characterization of miRNAs and their target genes associated with seed development through small RNA sequencing in chickpea
(Springer Nature Publishing AG, 2021) Pradhan, Seema; Verma, Subodh; Chakraborty, Anirban; Bhatia, Sabhyata
Multiple studies have attempted to dissect the molecular mechanism underlying seed development in chickpea (Cicer arietinum L.). These studies highlight the need to focus on the role of miRNAs in regulating storage protein accumulation in seeds. Therefore, a total of 8,856,691 short-read sequences were generated from a small RNA library of developing chickpea seeds and were analyzed using miRDeep-P to identify 74 known and 26 novel miRNA sequences. Known miRNAs were classified into 22 miRNA families with miRNA156 family being most abundant. Of the 26 putative novel miRNAs identified, only 22 could be experimentally validated using stem loop end point PCR. Differential expression analyses led to the identification of known as well as novel miRNAs that could regulate various stages of chickpea seed development. In silico target prediction revealed several important target genes and transcription factors like SPL, mediator of RNA Polymerase II transcription subunit 12, aspartic proteinase and NACs, which were further validated by real-time PCR analysis. A comparative expression analysis in chickpea genotypes with contrasting seed protein content revealed one known (Car-miR156h) and two novel miRNA (CarnovmiR7 and Car-novmiR23) candidates to be highly expressed in the LPC (low protein content) chickpea genotypes, targets of which are known to regulate seed storage protein accumulation. Therefore, this study provides a useful resource in the form of miRNA and their targets which can be further utilized to understand and manipulate various regulatory mechanisms involved in seed development with the overall aim of improving yield and nutrition attributes in chickpea.