Browsing by Author "S.K. Gond"

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Bio-control potential in Cladosporium sp. (MCPL - 461), against a noxious weed Parthenium hysterophorus L
(Triveni Enterprises, 2009) Anuj Kumar; V.C. Verma; S.K. Gond; V. Kumar; R.N. Kharwar
The phenological survey of Parthenium hysterophorus L., in and around the campus of Banaras Hindu University (BHU) was done for about two years (2004-06). During Nov. 2004, a few Parthenium plants were found diseased, and symptoms were restricted to the flowers, buds, and inflorescences. The disease causes sterility and reduces seed viability, which was observed with seed germination test from infected and healthy plants. The fungal pathogen was isolated and identified as Cladosporium sp. (MCPL-461). The severity of pathogen to the reproductive organs led to serious damages of the Parthenium plants. Thus in vitro and in vivo experiments were conducted to determine the bio-control potential of Cladosporium sp. (MCPL 461) against Parthenium weed. A combinatorial effort of Cladosporium sp. (MCPL 461) bio-control potential was evaluated with different culture media, incubation periods and spores strength. Spore suspension of 105 to 1012 spores ml-1 were used to spray on healthy Parthenium plants, and it was found that severe infection symptoms were appeared at 1010 to 1012 spores ml-1 suspension. LD50 was found at 107 spores ml-1. To enhance the myco-herbicide activity 3% sucrose was added to the spore suspension, which further resolute the bio-control efficacy of the isolates. Only 20-30% seeds of infected plants could germinate. However the safety of non-targeted and wild plants was also tested with Lantana camera, Chromolaena odorata and found that suspension up to 1012 spores ml-1 were not sufficient for disease outbreak in them. © Triveni Enterprises, Lucknow (India).
Diversity and antimicrobial activity of endophytic fungal community isolated from medicinal plant Cinnamomum camphora
(2012) R.N. Kharwar; A.L. Maurya; V.C. Verma; Anuj Kumar; S.K. Gond; Ashish Mishra
To study the diversity, distribution and community structure of endophytic fungi, a medicinal plant Cinnamomum camphora (L.) Presl., was selected from ayurvedic garden of Banaras Hindu University (BHU), Varanasi, India. Differences were observed between the endophytic myco-population of young and mature tissues of leaf, stem and petiole. The leaf segments with midrib (43.93 %, Isolation Frequency) were found to have more endophytic isolates than the vein less foliar segments (21.21 %), however, the segments with lateral veins (34.84 %) are comparatively closer to the midrib segments in endophytic recovery. The mature tissues are found to harbor more endophytic diversity than the young ones. It was observed that some endophytes restrict the probable invasion of other endophytes in their respective tissues, and thus defend their tissue specificity. The endophytic microbes obtained in this study are evaluated for their antimicrobial activity, against an array of human and plant pathogens. Pestalotiopsis sp. showed significant inhibitory activity against Phytophthora cryptogea (57.7 %), Pythium aphanidermatum (54.5 %) and Microsporum nanum (51.4), while Phomopsis sp. inhibited P. aphanidermatum moderately. This preliminary work not only resolutes the understanding about plant-endophytes interactions and distribution within the host, but also provides platform for screening and isolation of novel natural antimicrobial compounds, that may be utilized in designing novel drugs for sustainable relief to the mankind. © 2012 The National Academy of Sciences, India.
Diversity and biopotential of endophytic fungal flora isolated from eight medicinal plants of Uttar Pradesh, India
(Springer India, 2014) R.N. Kharwar; Ashish Mishra; Vijay K. Sharma; S.K. Gond; S.K. Verma; A. Kumar; Jitendra Kumar; D.K. Singh; J. Goutam
Endophytic fungi are hidden diversity mines of microbes that reside in the healthy and symptomless interior of plant tissues without causing any harmful effects. This chapter focuses on fungal endophytic diversity of eight medicinal plants of Uttar Pradesh, India with their biopotential ability. Total of 4,002 (38.38 % CF) endophytic isolates were recovered from 10,425 segments representing 131 endophytic fungal species belonging to different fungal classes. Out of 4,002 isolates, hyphomycetes were more pronounced with 71.43 % recovery followed by coelomycetes 16.61 %, ascomycetes 6.59 %, mycelia sterilia or unidentified 5.32 % and least from zygomycetes 0.020 %. Among total endophytic fungal species isolated, Cladosporium cladosporioides (3.39 % CF) was found to be the most dominated taxa followed by Alternaria alternata (2.35 % CF), Curvularia lunata (2.13 % CF), Aspergillus niger (1.95 % CF), Chaetomium globosum (1.85 % CF), Nigrospora oryzae (1.57 % CF) and Phoma glomerata (1.09 % CF). From a total of 131 endophytic species, 101 were tested for their antimicrobial and antioxidant activity. Out of 47 active species, 29.78 % displayed antibacterial activity, 27.65 % showed antifungal activity, 38.29 % exhibited antibacterial and antifungal activity both while only 4.25 % displayed antimalarial as well as antioxidant activity. Twenty-one endophytic fungal species were tested for extracellular production of amylase, xylanase and phosphate solubilization where 76.19 % found to produce amylase, 23.80 % for xylanase and 14.28 % exhibited phosphate-solubilization activity. © Springer India 2014 This work is subject. All rights reserved.
Endophyte roles in nutrient acquisition, root system architecture development and oxidative stress tolerance
(John Wiley and Sons Inc, 2021) S.K. Verma; P.K. Sahu; K. Kumar; G. Pal; S.K. Gond; R.N. Kharwar; J.F. White
Plants associate with communities of microbes (bacteria and fungi) that play critical roles in plant development, nutrient acquisition and oxidative stress tolerance. The major share of plant microbiota is endophytes which inhabit plant tissues and help them in various capacities. In this article, we have reviewed what is presently known with regard to how endophytic microbes interact with plants to modulate root development, branching, root hair formation and their implications in overall plant development. Endophytic microbes link the interactions of plants, rhizospheric microbes and soil to promote nutrient solubilization and further vectoring these nutrients to the plant roots making the soil-plant-microbe continuum. Further, plant roots internalize microbes and oxidatively extract nutrients from microbes in the rhizophagy cycle. The oxidative interactions between endophytes and plants result in the acquisition of nutrients by plants and are also instrumental in oxidative stress tolerance of plants. It is evident that plants actively cultivate microbes internally, on surfaces and in soils to acquire nutrients, modulate development and improve health. Understanding this continuum could be of greater significance in connecting endophytes with the hidden half of the plant that can also be harnessed in applied terms to enhance nutrient acquisition through the development of favourable root system architecture for sustainable production under stress conditions. © 2021 The Society for Applied Microbiology
Induction of abiotic stress tolerance in plants by endophytic microbes
(John Wiley and Sons Inc, 2018) R. Lata; S. Chowdhury; S.K. Gond; J.F. White
Endophytes are micro-organisms including bacteria and fungi that survive within healthy plant tissues and promote plant growth under stress. This review focuses on the potential of endophytic microbes that induce abiotic stress tolerance in plants. How endophytes promote plant growth under stressful conditions, like drought and heat, high salinity and poor nutrient availability will be discussed. The molecular mechanisms for increasing stress tolerance in plants by endophytes include induction of plant stress genes as well as biomolecules like reactive oxygen species scavengers. This review may help in the development of biotechnological applications of endophytic microbes in plant growth promotion and crop improvement under abiotic stress conditions. Significance and Impact of the Study: Increasing human populations demand more crop yield for food security while crop production is adversely affected by abiotic stresses like drought, salinity and high temperature. Development of stress tolerance in plants is a strategy to cope with the negative effects of adverse environmental conditions. Endophytes are well recognized for plant growth promotion and production of natural compounds. The property of endophytes to induce stress tolerance in plants can be applied to increase crop yields. With this review, we intend to promote application of endophytes in biotechnology and genetic engineering for the development of stress-tolerant plants. © 2018 The Society for Applied Microbiology
Induction of cryptic metabolite production through epigenetic tailoring in Colletotrichum gloeosporioides isolated from Syzygium cumini
(Springer International Publishing, 2017) V.K. Sharma; J. Kumar; D.K. Singh; A. Mishra; S.K. Gond; S.K. Verma; A. Kumar; G. Singh; R.N. Kharwar
Recent advancement in the fungal molecular genetics has established that fungi have numerous genes or gene clusters that remain silent or unexpressed under the normal conditions. These genes can be activated through epigenetic modifiers to produce a wide range of potential bioactive metabolites of agricultural and pharmaceutical values. In this study one DNA methyltransferase inhibitor (5-azacytidine) and one histone deacetylase inhibitor (sodium butyrate) were used for the epigenetic treatment to the Colletotrichum gloeosporioides isolated from the surface-sterilized leaves of S. cumini. The crude compounds isolated from the epigenetically treated C. Gloeosporioides were observed to exhibit increased antibacterial activity against human bacterial pathogens (Aeromonas hydrophila, Enterococcus faecalis, Escherichia coli, Salmonella typhi, Shigella boydii, and Staphylococcus aureus). In terms of antibacterial efficacy, the secondary metabolites extracted from the culture treated with 5-azacytidine were found to be the most effective against all the tested bacterial pathogens followed by cultures treated with sodium butyrate and the combined treatment of both 5-azacytidine and sodium butyrate compared to control except against the S. Typhi. The HPLC profiling showed that fungal crude metabolite compounds from different treatments of epigenetic modulators activated the production of additional metabolites compared to the untreated control. Further, the total amount of secondary metabolites extracted with ethyl acetate from treated cultures showed severalfold increase. This indicates toward the change in the expression of some cryptic genes or gene cluster through epigenetic modification by 5-azacytidine and/or sodium butyrate treatment(s). © 2017, Springer International Publishing AG. All rights reserved.
Role of different variables on site-specific isolation and distribution patterns of soil mycoflora from Varanasi
(2013) Anuj Kumar; S.K. Gond; A. Mishra; V.K. Sharma; S.K. Verma; R.N. Kharwar
During present study, 513 isolates were recovered from 15 different experimental sites. For fungal recovery, PDA medium proved better over Czapek's dox agar medium (CDA), while Waksman dilution method showed higher isolates recovery than Warcup's soil plate method. Thirty filamentous fungi were recovered of which Aspergillus, Alternaria, Cladosporium, and Fusarium were dominant. Aspergillus niger and A. fumigatus showed a high frequency of occurrence and were isolated @ 80 ×103 CFU/g and 47× 103 CFU/g, respectively from dry, moist and humid soil samples, while Penicillium notatum (37×103 CFU/g), Nigrospora oryzae (30 ×103 CFU/g), Rhizopus nigricans (32×103 CFU/g), Trichoderma viride (24×103 CFU/g) were isolated with moderate frequency. Fifty three isolates were recovered from site 10 (Agriculture field, BHU) which was highest whereas, 12 isolates were recovered from site 1 (Cantt Railways Station). Consequently, the site 10 had the maximum CFU value (53×103 CFU/g) whereas site 1 had the lowest (12 ×103 CFU/g). A higher percentage of soil fungi isolated have preferred the acidic pH range. Mean of fungal isolates was higher in moist (37.60), followed by humid (34.50) and dry (30.20) conditions. Bray-Curtis cluster analysis was done to understand that several variables are responsible for the diversity and occurrence of soil fungi.
Role of fungal endophytes in plant protection
(CABI Publishing, 2010) S.K. Gond; V.C. Verma; A. Mishra; A. Kumar; R.N. Kharwar
Endophytes are the microorganisms that reside inside healthy plant tissues without causing any detectable disease symptoms to the host. Often, each and every plant harbours either one or a battery of endophytic microorganisms. The study of endophytes is now on a voyage of interest, not only because of their role in fi lling the divide between discovered and undiscovered microbial diversity, but also due to their harbouring a great potential to produce novel natural products. Other than soil, higher plants also act as an alternative resource to isolate potential microorganisms. Natural compounds ranging from crop protection to human welfare have been isolated from this alternative source of endophytes. Several anticancer, antibiotic, antimycotic, antiviral, antioxidant, nematicide, insecticide and immunosuppressive compounds have been reported from endophytes, such as cytochalasines, ambuic acid, oocydin, jesterone, cryptocandin, lolitrem B, and 3-hydroxypropionic acid and taxol, etc. Many of them produce some toxic alkaloids and protect their hosts from herbivores. They also improve the growth and yield of crops under various stressed conditions. Endophytic fungi have been emerging as a new tool in genetic engineering, the pharmaceutical industry and in crop protection as well. In this chapter, the ability and role of endophytic fungi to ward off pests and environmental stresses on plants is discussed. © CAB International 2010.
Selection of natural strains of fungal endophytes from Azadirachta indica A. Juss, with anti-microbial activity against dermatophytes
(2008) V.C. Verma; S.K. Gond; Ashish Mishra; A. Kumar; R.N. Kharwar
Increasing drug resistance among bacteria, fungi and other pathogenic microbes and the remarkable increase in the incidence of fungal infections like dermatomycoses in the world population underscore our inadequacy to deal with them. Thus there is an urgent need to search chemically novel, natural, renewable and safe anti-microbial substances that can offer opportunity for innovation of new drugs to combat the widespread dermatomycoses. Six fungal endophytic strains (Scytalidium sp. MCPL AzF 023, Pestalotiopsis sp. MCPL AzB 153, Colletotrichum sp. MCPL AzR 249, Alternaria sp. MCPL AzL 198, Nigrospora sp. MCPL AzS 076, and Chloridium sp. MCPL AzR 142) from Azadirachta indica A Juss were screened and evaluated their efficacy against dermatophytes Trichophyton and Microsporum. The susceptibility test was performed by whole plate diffusion method. The EtOAc extracted Scytalidium, Chloroform extracted Nigrospora, Colletotrichum, and Alternaria, ethyl ether extracted Nigrospora in particular significantly reduced the growth of dermatophytes. The MIC ranged from 125-400 μg ml-1 for Trichophyton and 200-350 μg ml-1 for Microsporum while the MFC ranged from 230 to 425 μg ml-1. The chloroform, EtOAc, and ethyl ether were the solvents that might dissolve major active fractions of Pestalotiopsis, Scytalidium and Chloridium. The growth patterns of dermatophytes were also significantly distorted at concentration of 100 μg ml-1 (below MIC), which is statistically significant with reference to untreated fungi. In this study, we recovered bioactive fractions that might be chemically novel and effective against dermatophytes particularly and on other human and plant pathogens in general. Thus we might anticipate some new bioactive compounds to design new effective drugs against dermatomycoses initially. © 2008 Bentham Science Publishers Ltd.
Study of endophytic fungal community from different parts of Aegle marmelos Correae (Rutaceae) from Varanasi (India)
(2007) S.K. Gond; V.C. Verma; A. Kumar; V. Kumar; R.N. Kharwar
Endophytic fungi were isolated from healthy, living, and symptomless tissues of inner bark, leaf, and roots of Aegle marmelos, a well-known medicinal plant, growing in different parts of India including Varanasi. A total of 79 isolates of endophytic fungi were isolated, representing 21 genera, adopting a standard isolation protocol. Members of the deuteromycotina were more prevalent than ascomycotina and others. The result was quite encouraging in terms of maximum isolates recovery from hyphomycetes (78.5%) followed by ascomycetes (8.9%) and coelomycetes (7.6%) respectively, which corroborates previous studies in same area. However, 5.1% isolates remained unidentified and were classified under Mycelia Sterilia. No isolate was obtained from either basidiomycotina or from zygomycotina. Fusarium spp. had maximum colonization frequency (8.00%) in this plant. The other dominant endophytic genera were Aspergillus spp., Alternaria sp., Drechslera sp., Rhizoctonia sp., Curvularia sp., Nigrospora sp., and Stenella sp. Only two ascomycetous members Chaetomium globosum and Emericella sp. (perfect state of Aspergillus sp.) were obtained from the bark sample. These results indicated that distribution of endophytic fungi within the A. marmelos is not even. Bark harbors more endophytic fungi than leaf and root. © 2007 Springer Science+Business Media B.V.
The endophytic mycoflora of bark, leaf, and stem tissues of Azadirachta indica A. Juss (Neem) from Varanasi (India)
(2007) V.C. Verma; S.K. Gond; A. Kumar; R.N. Kharwar; Gary Strobel
A systematic study was made of the endophytes of Azadirachta indica A. Juss (the neem tree) growing in several of its natural habitats in India. A total of 233 isolates of endophytic fungi representing 18 fungal taxa were obtained from segments of bark, stem, and leaves of this tree. Hyphomycetes (62.2%) were the most prevalent followed by the Coelomycetes (27.4%) and Mycelia Sterilia (7.7%). As mathematically determined, the maximum species richness and frequency of colonization of endophytes appeared in leaf segments rather than stem and bark tissues from each location. Endophytic colonization frequency was also greater in leaves (45.5%) than bark (31.5%). The leaf samples from all locations were nearly constant in their endophytic composition, whereas bark samples showed maximum diversity at different locations. Inter-site comparisons for endophytic diversity, however, were not significantly different with Loc1 and Loc2 having a maximum of 66.67% J c. The smallest similarity was between Loc2 and Loc3 of 54.17% J c. The dominant endophytic fungi isolated were Phomopsis oblonga, Cladosporium cladosporioides, Pestalotiopsis sp., Trichoderma sp, and Aspergillus sp. Genera such as Periconia, Stenella, and Drechslera are reported here for the first time as endophytes from this host plant. This report illustrates the value of sampling different tissues of a given plant in several locations to obtain the greatest species diversity of endophytes. The rich and sizeable collection of endophytic fungi from this specific plant may represent a unique source of one or more of the interesting and useful bioactive compounds normally associated with A. indica such as the azadirachtins and related tetranortriterpenoids. © 2007 Springer Science+Business Media, LLC.
Will fungi be the new source of the blockbuster drug taxol?
(Elsevier Ltd, 2014) S.K. Gond; R.N. Kharwar; J.F. White
Taxol (paclitaxel) is widely used for the treatment of various kinds of cancers. Originally, the major source of taxol was bark of the Pacific yew tree (. Taxus brevifolia). However, this proved devastating to natural populations of the trees. To protect the Pacific yew, alternatives to the use of trees are sought. One solution is the use of taxol or its precursors derived from fungi. A large number of endophytic fungi that reside within healthy plants have been reported to be taxol producers. However, fungal epiphytes, pathogens and saprophytes have also been found to produce taxol. Several strains of fungi belonging to species Metarhizium anisopliae and Cladosporium cladosporioides MD2 are very promising, producing taxol at levels up to 800μg/L. This review examines the potential for production of taxol from fungi. The biology of taxol synthesis in fungi and measures which may improve taxol yield are also discussed. © 2014 The British Mycological Society.