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Articles by R.K. Gaur
Total Records ( 12 ) for R.K. Gaur
  N. Sharma , K.P. Sharma , R.K. Gaur and V.K. Gupta
  Plants represent the major component of biota and have the capability to synthesize their food through the process of photosynthesis. Physiological and environmental changes affect their health and make them vulnerable to variety of diseases thus directly or indirectly affect other components of ecosystem. A large number of environmental issues are linked with the eradication of plant diseases with chemical compounds. Most of these diseases are caused by fungal and insect pathogens. Chitin is the main structural component of these organisms and thus the enzyme responsible to hydrolyze chitin content are receiving attention in regard to their development as biopesticides or chemical defense proteins in transgenic plants and in microbial biocontrol agents. Therefore, understanding the overview of chitinase will provide a basis for improving the pathogenic activity of potential biocontrol strains, for developing novel biological control strategies and for exploring their roles in the plant defense. The present review describes the properties of chitinase with respect to plant health improvement.
  R. Prajapat , R.K. Gaur and A. Marwal
  Structural bioinformatics is concerned with computational approaches to predict and analyze the spatial structure of proteins and nucleic acids by using different tools and techniques. The aim of present study was to carry out the homology modeling study of AC1 Rep protein and docking between α-lactalbumin and Rep protein of Begomovirus by using modeling and docking (Hex 6.3) softwares. This model show that 35% identity is enough for receptor based antiviral agent designing. The closest homologue of Rep protein was 1L2M|A, with the highest sequence identity of 81% that was selected as representative model using homology modeling softwares. The model was validated by using protein structure checking tools such as RAMPAGE server and Prochek for reliability. On the basis of RMS and energy values, the best docking orientation -1.00 was selected. This study will be used for the screening of inhibitors against Begomoviral proteins and can be further applied in future antiviral agent designing.
  A. Marwal , R. Prajapat , A. Sahu and R.K. Gaur
  Recombination plays a key role in the evolution of geminiviruses and may be contributing to the emergence of new strains/species. The high frequency of mixed infections of begomoviruses in different host allows the emergence of new viruses arising from recombination among species. With the development of computational recombination detection tools and an increasing number of available genome sequences, many studies have reported evidence of recombination in a wide range of Geminiviridae genera. The in silico analysis suggested that interspecific recombination has resulted significant diversity among geminiviruses and emergence of new geminivirus diseases.
  A. Marwal , R. Prajapat , A. Sahu and R.K. Gaur
  Recombination plays a key role in the evolution of Begomovirus and may be contributing to the emergence of new species. With the development of computational recombination detection tools and an increasing number of available genome sequences, many studies have reported evidence of recombination. Begomovirus associated symptoms were observed in Jasminum sambac and Millingtonia hortensis plants growing in crop fields of Lakshmangarh, Rajasthan (India). Amplification of a PCR product was found up to the expected size (~550 bp). The PCR product was cloned and partially sequenced and it was utilized for in silico characterization. The in silico analysis suggested that interspecific recombination has resulted in significant diversity among Begomovirus.
  Avinash Marwal , Rajneesh Prajapat , Anurag Kumar Sahu and R.K. Gaur
  Geminivirus are a large diverse family of plant viruses that infect a broad variety of plants and cause significant loss to Agricultural crops and ornamental plants in India. The vector white fly is the carrier of these viruses. This review focuses on the current status of Geminivirus in India and research related to it. Researches being carried out on Geminivirus include their molecular characterization, serological and computational characterization. Many costly measures in controlling the infections and increasing the crop yield have been applied. A cost effective appraise against these viruses is the relevance of RNAi Technology. RNAi is a challenging approach in which an interference RNA molecule put a check halt on the multiplication of Begomovirus in plants through its ability to form a Dicer complex.
  Pooja Sharma , Anurag Kumar Sahu , Rakesh Kumar Verma , Ritesh Mishra and R.K. Gaur
  A survey conducted in potato growing tracts of Rajasthan (India), covering 25 fields in 15 villages, revealed the occurrence of potato mosaic disease. A potyvirus (Potato virus Y, PVY) causing severe mosaic mottling in potato (Solanum tuberosum) was identified. The aim of this study to characterize this potyvirus on the basis of biological, serological and partial nucleotide sequence properties from different locations of Rajasthan. Electron microscopy of this virus revealed flexuous filamentous virus particles of 750x15 nm and showed positive result against antiserum specific for PVY. RT-PCR assay was assessed using potyvirus specific primers designed against the core region of the Nib and Coat Protein (CP). cDNA fragments of Nib and CP gene, 323 and 353 bp were obtained, respectively. Sequencing and analysis of the amplicons showed that the virus is closely related to Potato virus Y. Sequence analysis reveals that virus isolate (PVY-PS) showed 93-97% similarity with other worldwide PVY isolates. Nucleotide sequences have been submitted to NCBI data base under the accession number-KC753451and KC753450.
  V.K. Gupta , A.K. Misra , R.K. Gaur , P.K. Jain , D. Gaur and Saroj Sharma
  Guava (Psidium guajava L.) is an important fruit crop of subtropical countries. It is grown almost in all the states of India. It is a hardy crop and is cultivated successfully even in neglected soils and is attacked by a large number of pathogens, mainly fungi. Wilt is the most destructive disease for guava plant in India and losses due to this disease are substantial. Psidium guajava wilt is known to occur from India, Latin America, Malaysia, Pakistan, South Africa, South Asia and Taiwan. Wilt of guava from India was first reported in 1935 from Allahabad. The disease is soil-borne and is difficult to control. Wilt is predominantly caused by the species of Fusarium, of which F. oxysporum is generally the main cause. The other species of Fusarium i.e., Fusarium solani are also dominates in isolation. Since, the disease results in the complete mortality of the affected plants, the loss is total. Although, severe loss is there in the annual crops also, huge monitory losses occur especially in perennial fruit trees as it is a loss of labour of several years. Guava is a crop where this disease is very serious and it can be said that this is the only disease of guava which is threatening guava cultivation in India. It causes monitory as well as nutritional loss. The present communication, deals guava wilt to depict its present status.
  Avinash Marwal , Rajneesh Prajapat and R.K. Gaur
  The aim of this study were to present and highlight the in silico recombination analysis approach for in depth study about the nature of the virus. To detect the possibility of recombination in betasatellite and alphasatellite, Recombination Detection Program (RDP) was utilized, which is based on a pair wise scanning approach. The betasatellite and alphasatellite genomes were isolated from an ornamental plant Marigold and is identified as a new recombinant species, sharing nucleotide identity with other isolates reported from China and Pakistan. One factor favoring the spread of viruses among these plants is that many dicotyledonous species in India are hosts of whiteflies of the B. tabaci complex, which are the known or likely vectors of all the viruses. The present study remarkably suggests that the exchange of DNA with other viruses would create a new disease complex posing a serious threat to agriculture crops and horticulture ornamental plants production.
  Kusum Dhakar , V.K. Gupta , M.S. Rathore and R.K. Gaur
  Gene silencing can occur either repression of transcription, termed Transcriptional Gene Silencing (TGS) or through mRNA degradation, termed post transcriptional gene silencing. Transcriptional gene silencing results from a marked decrease in tracription and hypermethylaton of genes affected. RNAi or PTGS discovered as a natural anti-viral system in plants. Studies revealed that geminiviruses which replicates in nucleus can induce PTGS and become the target for it. RNAi has a strong potential to reduce the infection of geminiviruses. Several studies are already conducted on different genes geminiviruses and that are used for generating virus resistance plants. Our main objective of present study is to develop resistance against geminivirus using a novel strategy based on RNAi. Here we summarise how the RNAi mechanism works against begomovirus infection in plants and how we can utilize it to reduce the losses.
  R. Prajapat , R.K. Gaur , R. Raizada and V.K. Gupta
  Structural bioinformatics is concerned with computational approaches to predict and analyse the spatial structure of proteins and nucleic acids. The 3D models can be obtained most easily if the 3D structure of a homologous protein is known (homology modeling, comparative modeling). Homology modeling or comparative modeling is based on the fact that a structure of a protein can be reliably modeled when its sequence is sufficiently similar to a protein sequence with known 3D structure. The Geminivirus taxonomic group of plant viruses is characterized by geminate particles and genomes consisting of single-stranded circular DNA (sscDNA) molecules of about 2-5 to 2.8 kb in size. Here, we analyzed the genetic diversity of begomovirus from different crops and weeds of different region on the basis of homology modeling. This high degree of genetic diversity suggests a recent transfer of indigenous begomovirus from wild hosts into economic important crops.
  Avinash Marwal , Rajneesh Prajapat and R.K. Gaur
  Earlier reported the molecular characterization of complete genome of a begomovirus and its satellite molecules isolated from an ornamental plant Marigold i.e., Ageratum enation virus (AEV: KC589699), Ageratum leaf curl betasatellite (ALCB: KC589700) and Marigold leaf curl alphasatellite (MLCuA: KC206078). It presented and highlighted the computational approach for prediction of binding sites in protein molecules of the three begomovirus components for in depth study using two servers. Thus, in order to take a step forward to find a cure against such viruses that causes major crop loss worldwide.
  P.K. Jain , V.K. Gupta , R.K. Gaur , M. Lowry , D.P. Jaroli and U.K. Chauhan
  Environmental pollution with petroleum and petrochemical products (complex mixture of hydrocarbon) has been recognized as one of the most important serious current problem. People working in garage etc. are always exposed with oily sludge which are potent immunotoxicants and carcinogenic. Accidental leakages from petroleum carrying ships lead to oily layers over the water surface, possessing great threat to the existing flora and fauna. The currently used physical and chemical treatments are effective for the degradation of petroleum products but they lag behind in the desired properties, apart they frequently produce many hazardous compounds which are potent immunotoxicants and carcinogenic for living beings. In contrast, bioremediation is effective treatment in terms of efficacy, safety on long terms use, cost and simplicity of administration. However, for the foreseeable future, long term tolerance studies are needed before being recommended for large scale use.
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