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Venkataravanappa V.,Indian Institute of Horticultural Research | Venkataravanappa V.,Indian Institute of Vegetable Research | Jalali S.,Indian Institute of Horticultural Research | Krishna Reddy M.,Indian Institute of Horticultural Research
Virus Genes | Year: 2012

Yellow vein mosaic disease of okra is a whitefly transmitted begomovirus causing heavy economic loss in different parts of India. The okra isolate (OY131) of this virus from a bhendi plant [(Abelmoschus esculentus L.) Moench] showing yellow vein mosaic, vein twisting, reduced leaves, and a bushy appearance in the Palem region, New Delhi, India, was characterized in the present study. The complete DNA-A and DNA-B sequences have been determined and are comprised of 2,746 and 2,703 nucleotides, respectively. The betasatellite (DNA-β) component was absent in the sample. The genome organization was typically of biparite begomoviruses, which were characterized earlier. Comparison of DNA-A component with other known begomoviruses suggest that this virus, being only distantly related (<85.9% similarity with its nearest relative, BYVMV) to other known begomoviruses, is a new species. We have tentatively assigned the genome to a novel geminivirus species Bhendi yellow vein mosaic Delhi virus [BYVDV-IN (India: Delhi: okra)]. DNA-B showed highest sequence identity (87.8% identical) to that of a ToLCNDV (AY158080). The phylogenetic analysis of the present isolate is distinct from all other viruses; however clusters with ToLCNDV group infect different crops. The recombination analysis revealed that this isolate has sequences originated from ToLCNDV. This is the first known bhendi yellow vein mosaic disease associated bipartite begomovirus from India. © Springer Science+Business Media, LLC 2012.


Soni D.K.,Banaras Hindu University | Singh M.,Indian Institute of Vegetable Research | Singh D.V.,Institute of Life science | Dubey S.K.,Banaras Hindu University
BMC Microbiology | Year: 2014

Background: Listeria monocytogenes, a foodborne pathogen is ubiquitous to different environments including the agroecosystem. The organism poses serious public health problem. Therefore, an attempt has been made to gain further insight to their antibiotic susceptibility, serotypes and the virulence genes. Results: Out of the 10 vegetables selected, 6 (brinjal, cauliflower, dolichos-bean, tomato, chappan-kaddu and chilli), 20 isolates (10%) tested positive for L. monocytogenes. The prevalence of the pathogen in the respective rhizosphere soil samples was 5%. Noticeably, L. monocytogenes was absent from only cabbage, broccoli, palak and cowpea, and also the respective rhizospheric soils. The 30 isolates + ve for pathogenicity, belonged to serogroup 4b, 4d or 4e, and all were positive for inlA, inlC, inlJ, plcA, prfA, actA, hlyA and iap gene except one (VC3) among the vegetable isolates that lacked the plcA gene. ERIC- and REP-PCR collectively revealed that isolates from vegetables and their respective rhizospheric soils had distinct PCR fingerprints. Conclusions: The study demonstrates the prevalence of pathogenic L. monocytogenes in the selected agricultural farm samples. The increase in the number of strains resistant to ciprofloxacin and/or cefoxitin seems to pose serious public health consequences. © 2014 Soni et al.; licensee BioMed Central Ltd.


Singh A.K.,Banaras Hindu University | Singh M.,Indian Institute of Vegetable Research | Dubey S.K.,Banaras Hindu University
BMC Microbiology | Year: 2013

Background: The global area under brinjal cultivation is expected to be 1.85 million hectare with total fruit production about 32 million metric tons (MTs). Brinjal cultivars are susceptible to a variety of stresses that significantly limit productivity. The most important biotic stress is caused by the Brinjal fruit and shoot Borer (FSB) forcing farmers to deploy high doses of insecticides; a matter of serious health concern. Therefore, to control the adverse effect of insecticides on the environment including the soil, transgenic technology has emerged as the effective alternative. However, the reports, regarding the nature of interaction of transgenic crops with the native microbial community are inconsistent. The effect of a Bt transgenic brinjal expressing the bio-insecticidal protein (Cry1Ac) on the rhizospheric community of actinomycetes has been assessed and compared with its non-transgenic counterpart. Results: Significant variation in the organic carbon observed between the crops (non-Bt and Bt brinjal) may be due to changes in root exudates quality and composition mediated by genetic attributes of Bt transgenic brinjal. Real time quantitative PCR indicated significant differences in the actinomycetes- specific 16S rRNA gene copy numbers between the non-Bt (5.62-27.86) × 1011 g-1 dws and Bt brinjal planted soil (5.62-24.04) × 1011 g-1 dws. Phylogenetic analysis indicated 14 and 11, actinomycetes related groups in soil with non-Bt and Bt brinjal crop, respectively. Micrococaceaea and Nocardiodaceae were the dominant groups in pre-vegetation, branching, flowering, maturation and post-harvest stage. However, Promicromonosporaceae, Streptosporangiaceae, Mycobacteriaceae, Geodermatophilaceae, Frankiaceae, Kineosporaceae, Actisymmetaceae and Streptomycetaceae were exclusively detected in a few stages in non-Bt brinjal rhizosphere soil while Nakamurellaceae, Corynebactericeae, Thermomonosporaceae and Pseudonocardiaceae in Bt brinjal counterpart. Conclusion: Field trails envisage that cultivation of Bt transgenic brinjal had negative effect on organic carbon which might be attributed to genetic modifications in the plant. Changes in the organic carbon also affect the actinomycetes population size and diversity associated with rhizospheric soils of both the crops. Further long-term study is required by taking account the natural cultivar apart from the Bt brinjal and its near-isogenic non-Bt brinjal with particular reference to the effects induced by the Bt transgenic brinjal across different plant growth stages. © 2013 Singh et al.; licensee BioMed Central Ltd.


Chandra Rai A.,Indian Institute of Vegetable Research | Chandra Rai A.,Banaras Hindu University | Singh M.,Indian Institute of Vegetable Research | Shah K.,Banaras Hindu University
Plant Physiology and Biochemistry | Year: 2012

Water stress often leads to the accumulation of reactive oxygen species (ROS) and their excessive production alters the activities of enzymes involved in their removal. ZAT12 is a member of stress-responsive C2H2 type Zinc Finger Protein (ZFP) reported to control the expression of several stress-activated genes in plants through ROS signaling. The ZAT12-transformed tomato lines (cv. H-86 variety Kashi Vishesh) when subjected to water withdrawal for 7, 14 and 21 days revealed significant and consistent changes in activities of enzymes SOD, CAT, APX, GR and POD paralleled with an increased proline levels. Unlike that in wild-type tomato, the leaf superoxide anion and hydrogen peroxide concentrations in the transformed tomato plants did not alter much, suggesting a well regulated formation of free radicals suppressing oxidative stress in the latter. Results suggest BcZAT12-transformed tomato lines ZT1, ZT2 and ZT6 to be better adapted to drought stress tolerance by accumulation of osmolyte proline and increased antioxidant response triggered by the ZAT12 gene. Therefore, the ZAT12-transformed tomato cv. H-86 lines will prove useful for higher yield of tomato crop in regions affected with severe drought stress. © 2012 Elsevier Masson SAS.


Rai A.C.,Banaras Hindu University | Rai A.C.,Indian Institute of Vegetable Research | Singh M.,Indian Institute of Vegetable Research | Shah K.,Banaras Hindu University
Phytochemistry | Year: 2013

Efficient genetic transformation of cotyledonary explants of tomato (Solanum lycopersicum, cv. H-86, Kashi vishesh) was obtained. Disarmed Agrobacterium tumifaciens strain GV 3101 was used in conjugation with binary vector pBinAR containing a construct consisting of the coding sequence of the BcZAT12 gene under the regulatory control of the stress inducible Bclea1a promoter. ZAT12 encodes a C2H2 zinc finger protein which confers multiple abiotic stress tolerance to plants. Integration of ZAT12 gene into nuclear genome of individual kanamycin resistant transformed To tomato lines was confirmed by Southern blot hybridization with segregation analysis of T1 plants showing Mendelian inheritance of the transgene. Expression of ZAT12 in drought-stressed transformed tomato lines was verified in T2 generation plants using RT-PCR. Of the six transformed tomato lines (ZT1-ZT6) the transformants ZT1 and ZT5 showed maximum expression of BcZAT12 gene transcripts when exposed to 7 days drought stress. Analysis of relative water content (RWC), electrolyte leakage (EL), chlorophyll colour index (CCI), H2O2 level and catalase activity suggested that tomato BcZAT12 transformants ZT1 and ZT5 have significantly increased levels of drought tolerance. These results suggest that BcZAT12 transformed tomato cv. H-86 has real potential for molecular breeding programs aimed at augmenting yield of tomato in regions affected with drought stress. © 2012 Elsevier Ltd. All rights reserved.


Mishra K.K.,Indian Institute of Vegetable Research | Kumar A.,Indian Institute of Vegetable Research | Pandey K.K.,Indian Institute of Vegetable Research
World Journal of Microbiology and Biotechnology | Year: 2010

Fusarium wilt of tomato (Solanum lycopersicum Mill.) caused by Fusarium oxysporum f. sp. lycopersici (Sacc.) W. C. Snyder and H. N. Hans (Fol.), is most serious and versatile pathogen. Chemical control of disease is not satisfactory and biological control is an attractive and potential alternative to the use of chemicals to control fusarium wilt of tomato. No any bioagent is universally effective everywhere therefore, search for potential biocontrol agent is continuous process and mandatory for several and individual ecological niches. In this experiment biocontrol efficacy of five species of Aspergillus and five species of Trichoderma were evaluated in vitro against Fusarium oxysporum f. sp. lycopersici. In both the experiments (dual culture and culture filtrates) T. harzianum was found to be highly effective against the isolates of Fol. followed by A. niger biocontrol potential of A. terreus is least among all the isolates tested. Culture filtrates obtained from A. luchuensis exerted least inhibition of Fol. The most sensitive isolate of Fol. against all the antagonists tested was identified as IIVR-2 (Fol. 9). Inherent diversity among Fol. isolates, from different tomato growing regions in India, was determined using RAPD primers. The genetic similarity coefficients ranged from 0. 20 to 0. 96, indicating that no any two or more isolates were 100% similar. RAPD profiles revealed up to 20% genetic diversity among ten isolates of Fusarium oxysporum f. sp. lycopersici. © Springer Science+Business Media B.V. 2009.


Singh A.K.,Banaras Hindu University | Singh M.,Indian Institute of Vegetable Research | Dubey S.K.,Banaras Hindu University
Journal of Applied Microbiology | Year: 2014

Aims: The objective of this study was to investigate the influence of Cry1Ac gene expressing brinjal (VRBT-8) on the rhizospheric fungal community structure. Methods and Results: qPCR indicated variations in the fungal ITS rRNA copy numbers of non-Bt (1·43-4·43) × 109 g-1 dws and Bt (1·43-3·32) × 109 g-1 dws plots. Phylogenetic analysis of ITS rRNA clones indicated fungal-related group majority of being Ascomycota compared to that of Basidiomycota and Zygomycota in non-Bt- and Bt-planted soils. Sordariomycetes was the dominant class detected in all the stages. Conclusions: Despite the variations in the population size and the distribution pattern observed across the non-Bt and Bt brinjal, plant-growth-dependent variability was more prominent compared with genetic modification. Therefore, this study concludes that genetic modification of brinjal crop has minor effect on the fungal community. Significance and Impact of the Study: Brinjal, the important solanaceous crop, is also prone to attack by many insect pests, especially by Leucinoides orbonalis, resulting in significant losses in the crop yield. However, the reports on the effect of transgenic crops and the associated microbial community are inconsistent. The present communication takes into account for the first time the possible interactions between Bt brinjal and the associated fungal community; the latter playing a significant role in maintaining soil fertility. As this study is limited to the structural diversity of fungal community, additional information regarding the functional diversity of the group seems imperative before recommending the commercialization of GM crops. © 2014 The Society for Applied Microbiology.


A 2-year field study was conducted to develop an eco-friendly field application method for controlling root-knot disease of eggplant (Solanum melongena). The test sites were heavily infested with the root-knot nematode, Meloidogyne incognita. The efficacy of neem cake (1.5 t ha-1), talc-based preparations of Pseudomonas fluorescens (10 kg ha-1) and Trichoderma harzianum (10 kg ha-1) as soil application and seed treatment (10 g (kg seed)-1) were tested to develop an integrated nematode management module against M. incognita infecting eggplant. Neem cake, P. fluorescens and T. harzianum alone and in combinations significantly reduced the incidence of root-knot disease of eggplant. Fresh and dry weight of shoots were higher in the plant where neem cake, P. fluorescens and T. harzianum had been applied, than in both M. incognita-infected plants and other treatments. The best protection of disease, in terms of reduction in number of galls (81%) and reproductive factor (Pfâ̂•Pi < 0.5) of the nematode, was achieved through this treatment. It also enhanced yield of eggplant by up to 70%. It is suggested that integrated approach using organic amendment with bio-control agents to manage root-knot disease of eggplant under natural infestation is not only environmentally friendly but also more beneficial to growers. This approach also has potential for overcoming some of the efficacy problems that occur with application of individual biological control agent. © 2013 Koninklijke Brill NV, Leiden.


Sanwal S.K.,Indian Institute of Vegetable Research | Rai N.,Indian Institute of Vegetable Research | Singh J.,Indian Institute of Vegetable Research | Buragohain J.,ICAR Research Complex for NEH Region
Scientia Horticulturae | Year: 2010

Fresh rhizomes of 18 diploid and tetraploid genotypes of Indian ginger, including commercial cultivars and experimental genotypes, were assayed for gingerol content and antioxidant activity. The tetraploid ginger type was derived from the respective diploid ginger by shoot tip culture. [6]-Gingerol was identified as the major pungent phenolic compound in all samples (mean 1354.78 ± 470 μg/g), while [8]- (mean 180.94 ± 45 μg/g) and [10]-gingerol (mean 234 ± 79 μg/g) occurred in lower concentrations. The total gingerol content of the tetraploid type was much higher than that of the respective diploid type and especially the [10]-gingerol. Both diploid and tetraploid types of the cv. Meghalaya Local contained the highest level of gingerol. At both ploidy levels, the genotypes showed significant differences in phenols and antioxidant activities. Correlation of total phenolics with different antioxidant assay at both diploid and tetraploid level was linear and strong to moderate. For genotypes at both ploidy levels, antioxidant activity (BCO) was determined especially by [6]-gingerol while [8]- and [10]-gingerol did not affect BCO. These results demonstrated that in the tetraploid types of ginger, the gingerol content and antioxidant activity were higher than in the diploid ones. © 2010 Elsevier B.V. All rights reserved.


Vishwakarma P.,Banaras Hindu University | Singh M.,Indian Institute of Vegetable Research | Dubey S.K.,Banaras Hindu University
Biology and Fertility of Soils | Year: 2010

Four selected tropical field sites from India were studied to assess the diversity and community structure of methanotrophs in rice fields following crop harvest. The rate of methane oxidation ranged from 0.04 to 0.11 μmol L-1 h-1 g-1 dry weight in soils. Methanotrophic population size was high for the agriculture farm of Banaras Hindu University (BHU) site followed by agriculture farm of the Indian Institute of Vegetable Research (IIVR), Ghazipur, and Barkachcha. The cloning, restriction fragment length polymorphism, and sequence analyses of the pmoA gene fragment amplified from soil DNA extracts revealed the presence of type I and type II methanotrophs. The phylogenetic affiliation and community analysis based on the presence or absence of sequences showed that methanotrophs community composition in Barkachcha and Ghazipur soils was similar. IIVR soils, however, were quite different, while BHU soils were intermediate among the sites with regard to methanotrophic community composition. Diversity index of the methanotrophic community was high at the IIVR site. The study revealed that the rice harvest led to a change in type I methanotrophs from all the sites while type II community composition was almost uniform. © 2010 Springer-Verlag.

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