Vasu Arora

First whole genome based microsatellite DNA marker database of tomato for mapping and variety identification

BackgroundThe cultivated tomato is second most consumed vegetable of the world and is an important part of a diverse and balanced diet as a rich source of vitamins, minerals, phenolic antioxidants and antioxidant lycopene having anti-cancer properties. To reap benefit of genomics of the domestic tomato (Solanum lycopersicum L.) unravelled by Tomato Genome Consortium (The Tomato Genome Consortium, 2012), the bulk mining of its markers in totality is imperative and critically required. The solgenomics has limited number of microsatellite DNA markers (2867) pertaining to solanaceae family. As these markers are of linkage map having relative distance, the choice of selected markers based on absolute distance as of physical map is missing. Only limited microsatellite markers with limitations are reported for variety identification thus there is a need for more markers supplementing DUS test and also for traceability of product in global market.DescriptionWe present here the first whole genome based microsatellite DNA marker database of tomato, TomSatDB (Tomato MicroSatellite Database) with more than 1.4 million markers mined in-silico, using MIcroSAtellite (MISA) tool. To cater the customized needs of wet lab, features with a novelty of an automated primer designing tool is added. TomSatDB (http://cabindb.iasri.res.in/tomsatdb), a user-friendly and freely accessible tool offers chromosome wise as well as location wise search of primers. It is an online relational database based on “three-tier architecture” that catalogues information of microsatellites in MySQL and user-friendly interface developed using PHP (Hypertext Pre Processor).ConclusionBesides abiotic stress, tomato is known to have biotic stress due to its susceptibility over 200 diseases caused by pathogenic fungi, bacteria, viruses and nematodes. These markers are expected to pave the way of germplasm management over abiotic and biotic stress as well as improvement through molecular breeding, leading to increased tomato productivity in India as well as other parts of the world. In era of IPR the new variety can be identified based on allelic variation among varieties supplementing DUS test and product traceability.

PIPEMicroDB: microsatellite database and primer generation tool for pigeonpea genome

Molecular markers play a significant role for crop improvement in desirable characteristics, such as high yield, resistance to disease and others that will benefit the crop in long term. Pigeonpea (Cajanus cajan L.) is the recently sequenced legume by global consortium led by ICRISAT (Hyderabad, India) and been analysed for gene prediction, synteny maps, markers, etc. We present PIgeonPEa Microsatellite DataBase (PIPEMicroDB) with an automated primer designing tool for pigeonpea genome, based on chromosome wise as well as location wise search of primers. Total of 123 387 Short Tandem Repeats (STRs) were extracted from pigeonpea genome, available in public domain using MIcroSAtellite tool (MISA). The database is an online relational database based on ‘three-tier architecture’ that catalogues information of microsatellites in MySQL and user-friendly interface is developed using PHP. Search for STRs may be customized by limiting their location on chromosome as well as number of markers in that range. This is a novel approach and is not been implemented in any of the existing marker database. This database has been further appended with Primer3 for primer designing of selected markers with left and right flankings of size up to 500 bp. This will enable researchers to select markers of choice at desired interval over the chromosome. Furthermore, one can use individual STRs of a targeted region over chromosome to narrow down location of gene of interest or linked Quantitative Trait Loci (QTLs). Although it is an in silico approach, markers’ search based on characteristics and location of STRs is expected to be beneficial for researchers. Database URL: http://cabindb.iasri.res.in/pigeonpea/

In silico mining of putative microsatellite markers from whole genome sequence of water buffalo (Bubalus bubalis) and development of first BuffSatDB

BackgroundThough India has sequenced water buffalo genome but its draft assembly is based on cattle genome BTau 4.0, thus de novo chromosome wise assembly is a major pending issue for global community. The existing radiation hybrid of buffalo and these reported STR can be used further in final gap plugging and “finishing” expected in de novo genome assembly. QTL and gene mapping needs mining of putative STR from buffalo genome at equal interval on each and every chromosome. Such markers have potential role in improvement of desirable characteristics, such as high milk yields, resistance to diseases, high growth rate. The STR mining from whole genome and development of user friendly database is yet to be done to reap the benefit of whole genome sequence.DescriptionBy in silico microsatellite mining of whole genome, we have developed first STR database of water buffalo, BuffSatDb (Buffalo MicroSatellite Database (http://cabindb.iasri.res.in/buffsatdb/) which is a web based relational database of 910529 microsatellite markers, developed using PHP and MySQL database. Microsatellite markers have been generated using MIcroSAtellite tool. It is simple and systematic web based search for customised retrieval of chromosome wise and genome-wide microsatellites. Search has been enabled based on chromosomes, motif type (mono-hexa), repeat motif and repeat kind (simple and composite). The search may be customised by limiting location of STR on chromosome as well as number of markers in that range. This is a novel approach and not been implemented in any of the existing marker database. This database has been further appended with Primer3 for primer designing of the selected markers enabling researcher to select markers of choice at desired interval over the chromosome. The unique add-on of degenerate bases further helps in resolving presence of degenerate bases in current buffalo assembly.ConclusionBeing first buffalo STR database in the world , this would not only pave the way in resolving current assembly problem but shall be of immense use for global community in QTL/gene mapping critically required to increase knowledge in the endeavour to increase buffalo productivity, especially for third world country where rural economy is significantly dependent on buffalo productivity.

Development of a model webserver for breed identification using microsatellite DNA marker

BackgroundIdentification of true to breed type animal for conservation purpose is imperative. Breed dilution is one of the major problems in sustainability except cases of commercial crossbreeding under controlled condition. Breed descriptor has been developed to identify breed but such descriptors cover only “pure breed” or true to the breed type animals excluding undefined or admixture population. Moreover, in case of semen, ova, embryo and breed product, the breed cannot be identified due to lack of visible phenotypic descriptors. Advent of molecular markers like microsatellite and SNP have revolutionized breed identification from even small biological tissue or germplasm. Microsatellite DNA marker based breed assignments has been reported in various domestic animals. Such methods have limitations viz. non availability of allele data in public domain, thus each time all reference breed has to be genotyped which is neither logical nor economical. Even if such data is available but computational methods needs expertise of data analysis and interpretation.ResultsWe found Bayesian Networks as best classifier with highest accuracy of 98.7% using 51850 reference allele data generated by 25 microsatellite loci on 22 goat breed population of India. The FST values in the study were seen to be low ranging from 0.051 to 0.297 and overall genetic differentiation of 13.8%, suggesting more number of loci needed for higher accuracy. We report here world’s first model webserver for breed identification using microsatellite DNA markers freely accessible at http://cabin.iasri.res.in/gomi/.ConclusionHigher number of loci is required due to less differentiable population and large number of breeds taken in this study. This server will reduce the cost with computational ease. This methodology can be a model for various other domestic animal species as a valuable tool for conservation and breed improvement programmes.

SBMDb: first whole genome putative microsatellite DNA marker database of sugarbeet for bioenergy and industrial applications

DNA marker plays important role as valuable tools to increase crop productivity by finding plausible answers to genetic variations and linking the Quantitative Trait Loci (QTL) of beneficial trait. Prior approaches in development of Short Tandem Repeats (STR) markers were time consuming and inefficient. Recent methods invoking the development of STR markers using whole genomic or transcriptomics data has gained wide importance with immense potential in developing breeding and cultivator improvement approaches. Availability of whole genome sequences and in silico approaches has revolutionized bulk marker discovery. We report world’s first sugarbeet whole genome marker discovery having 145 K markers along with 5 K functional domain markers unified in common platform using MySQL, Apache and PHP in SBMDb. Embedded markers and corresponding location information can be selected for desired chromosome, location/interval and primers can be generated using Primer3 core, integrated at backend. Our analyses revealed abundance of ‘mono’ repeat (76.82%) over ‘di’ repeats (13.68%). Highest density (671.05 markers/Mb) was found in chromosome 1 and lowest density (341.27 markers/Mb) in chromosome 6. Current investigation of sugarbeet genome marker density has direct implications in increasing mapping marker density. This will enable present linkage map having marker distance of ∼2 cM, i.e. from 200 to 2.6 Kb, thus facilitating QTL/gene mapping. We also report e-PCR-based detection of 2027 polymorphic markers in panel of five genotypes. These markers can be used for DUS test of variety identification and MAS/GAS in variety improvement program. The present database presents wide source of potential markers for developing and implementing new approaches for molecular breeding required to accelerate industrious use of this crop, especially for sugar, health care products, medicines and color dye. Identified markers will also help in improvement of bioenergy trait of bioethanol and biogas production along with reaping advantage of crop efficiency in terms of low water and carbon footprint especially in era of climate change. Database URL: http://webapp.cabgrid.res.in/sbmdb/

Species specific approach to the development of web-based antimicrobial peptides prediction tool for cattle

Antimicrobial peptide (AMP) is part of innate immunity against microbial challenge.Out of 30,000 genes, very limited, just 100 AMPs are reported so far.Bulk discovery of novel AMP to reduce in vitro and in vivo protein evaluation is needed.Species specific approach un-attempted so far, has been reported with high accuracy.Web application developed using best model for therapeutic and industrial application. Antimicrobial peptides (AMPs) are the defence molecules of the host gaining extensive attention worldwide as these are natural alternative to chemical antibiotics. Machine learning techniques have capabilities to analyse large biological data for detection of hidden pattern in understanding complex underlying biological problems. Presently, development of resistance to chemical antibiotics in cattle is unsolved and growing problem which needs immediate attention. In the present study, attempt was made to apply machine learning algorithms such as Artificial Neuron Network (ANN) and Support Vector Machine (SVM). It was found that performance of SVM based models for in silico prediction/identification of AMPs of cattle is superior than ANN. A total of 99 AMPs related to cattle collected from various databases and published literature were taken for this study. N-terminus residues, C-terminus residues and full sequences were used for model development and identification/prediction. It was found that best SVM models in this case for C-terminus residues, N-terminus residues and full sequence were with kernels Radial Basis Function (RBF), Sigmoid and RBF with accuracy as 95%, 99% and 97%, respectively. These SVM models were implemented on web server and made available to users at http://cabin.iasri.res.in/amp/ for classification/prediction of novel AMPs of cattle. This computational server can accelerate novel AMP discovery from whole genome proteins of a given cattle species for bulk discovery with very high accuracy. This is the first successful attempt for development of species specific approach for prediction/classification of AMPs, which may be used further as a model in other species as well.

Analysis and functional annotation of expressed sequence tags of water buffalo.

An elucidated genome of domestic livestock river buffalo will contribute enormously to economy and better understanding of genome evolution as well. An attempt is made to obtain genomic information on buffalo, based on total Expressed Sequence Tags (ESTs) of Bubalus bubalis available in public domain. These ESTs were annotated and classified into 15 different functional categories based on their homology to the known proteins. Interestingly, 41.79% of the contigs were found to be buffalo specific novel ESTs with respect to other species used in analysis which needs further studies. Also, 224 pSNPs (putative Single Nucleotide Polymorphism) were detected. This study will provide a home base for further genomic studies of buffalo and comparative studies enabling a starting point for the genome annotation of the organism. Supplementary materials are available for this article online.