Antimicrobial resistance in fungal pathogens (both human and plant) is increasing alarmingly, lea... more Antimicrobial resistance in fungal pathogens (both human and plant) is increasing alarmingly, leading to massive economic crises. The existing anti-fungal agents are becoming ineffective, and the situation worsens on a logarithmic scale. Novel antifungals from unique natural sources are highly sought to cope sustainably with the situation. Metabolites from endophytic microbes are the bestfitted alternatives in this case. Endophytes are the untapped sources of 'plants' internal microbial population' and are promising sources of effective bio-therapeutic agents. Fungal endophytes were isolated from Tropaeolum majus and checked for antifungal activity against selected plant and human pathogens. Bioactive metabolites were identified through chromatographic techniques. The mode of action of those metabolites was evaluated through various spectroscopic techniques. The production of antifungal metabolite was optimized also. In particular VOCs (volatile organic compounds) of TML9 were tested in vitro for their anti-phytopathogenic activity. Ethyl acetate (EA) extract of cell-free culture components of Colletotrichum aenigma TML3 exhibited broad-spectrum antifungal activity against four species of Candida and the major constituents reported were 6-pentyl-2H-pyran-2-one, 2-Nonanone, 1 propanol 2-amino. The volatile metabolites, trans-ocimene, geraniol, and 4-terpinyl acetate, produced from Curvularia lunata TML9, inhibited the growth of some selected phyto pathogens. EA extract hampered the biofilm formation, minimised the haemolytic effect, and blocked the transformation of Candida albicans (MTCC 4748) from yeast to hyphal form with a Minimum Fungicidal Concentration (MFC) of 200-600 Āµg mL -1 . Central carbohydrate metabolism, ergosterol synthesis, and membrane permeability were adversely affected and caused the lethal leakage of necessary macromolecules of C. albicans. Volatile metabolites inhibited the growth of phytopathogens i.e., Rhizoctonia solani, Alternaria alternata, Botrytis cinerea, Cercospora beticola, Penicillium digitatum, Aspergillus fumigatus, Ceratocystis ulmi, Pythium ultimum up to 89% with an IC 50 value of 21.3-69.6 ĀµL 50 mL -1 and caused leakage of soluble proteins and other intracellular molecules. Citrusy sweet odor volatiles of TML9 cultured in wheat-husk minimised the infections of Penicillium digitatum (green mold), in VOC-exposed sweet oranges (Citrus sinensis). Volatile and nonvolatile antifungal metabolites of these two T. majus endophytes hold agricultural and pharmaceutical interests. Metabolites of TML3 have strong anti-Candida activity and require further assessment for therapeutic applications. Also, volatile metabolites of TML9 can be further studied as a source of antifungals. The present investigational outcomes bio-prospects the efficacy of fungal endophytes of Garden Nasturtium.
Journal of pure and applied microbiology, Feb 29, 2024
Endophytes represent a diverse domain of microorganisms with immense biotechnological potentialit... more Endophytes represent a diverse domain of microorganisms with immense biotechnological potentialities. Metabolites from endophytes, especially fungi, are useful in industrial as well as pharmaceutical aspects. Here, endophytic fungal isolates of Andrographis paniculata collected from the Tapobon, Junglemahal region of West Bengal, India, have been studied for their hydrolyzing enzyme production abilities. Out of eighty-one isolates, twenty-one were positive for amylase, protease, lipase, laccase, and tannase action. Microscopic features of positive isolates revealed that the enzyme producers were Aspergillus sp.
The increasing resistance of fungal pathogens against available antifungal agents is a serious th... more The increasing resistance of fungal pathogens against available antifungal agents is a serious threat to mankind. The most suitable solutions can only be found from untapped novel natural sources and endophytic metabolites are emerging as one of the dominant contributors in this eld. In the present study, Ethyl acetate (EA) extract of cell-free metabolites and volatile metabolites of endophytic fungi Colletotrichum aenigma TML3 and Curvularia lunata TML9, isolated from leaves of Tropaeolum majus, exhibited broad-spectrum antifungal activity against four species of Candida and nine taxa of postharvest phyto pathogens respectively. EA extract hampered the bio lm formation, minimised haemolytic effect, and blocked the transformation of Candida cells from yeast to hyphal form with an MFC of 200-600 Āµg mL - 1 . Central carbohydrate metabolism, ergosterol synthesis, and membrane permeability were adversely affected and caused the lethal leakage of necessary macromolecules of C. albicans. Volatile metabolites inhibited the growth of phytopathogens up to 89% with an IC 50 value of 21.3-69.6 ĀµL 50 mL - 1 and caused leakage of soluble proteins and other intracellular molecules. Citrusy sweet odor volatiles minimised the infections of Penicillium digitatum (green mold), in VOC-exposed sweet oranges (Citrus sinensis). In total twenty-one non-volatile and thirteen volatile metabolites were detected from the TML3, and TML9 endophytic fungi respectively. Citrusy sweet odor volatiles of TML9 cultured in wheathusk minimised the infections of Penicillium digitatum (green mold), in VOC-exposed sweet oranges (Citrus sinensis). Volatile and non-volatile antifungal metabolites of these two T. majus endophytes hold agricultural and pharmaceutical interests.
Seeking solutions from nature for solving one and all problems is the age-old practice for mankin... more Seeking solutions from nature for solving one and all problems is the age-old practice for mankind, and natural products are proved to be the most effective one for keeping up the balance of development as well as the "healthy, wealthy, and well" condition of mother nature. Fungal pathogens are proved to be a common and popular contaminant of agroecosystem that approximately causes 70-80% of total microbial crop loss. To meet the proper global increasing need of food products as a result of population explosion, managing agricultural system in an eco-friendly and profitable manner is the prime target; thus the word "sustainable agriculture" plays it part, and this package is highly effective when coupled with nature-derived fungicidal products that can minimize the event of fungal infections in agrarian ecosystem. Present study enlists the most common and effective natural products that might be of plant or microbial origin, their mode of action, day-by-day development of phytopathogenic resistance against the prevailing fungicides, and also their role in maintenance of sustainability of agricultural practices with special emphasis on their acceptance over the synthetic or chemical one. A large number of bioactive compounds ranging from direct plant (both cryptogams algae and moss and phanerogams)-derived natural extracts, essential oil of aromatic plants, and low-molecular-weight antimicrobial compounds known as phytoalexins to secondary metabolites that are both volatile and nonvolatile organic compounds of microbes (fungal and actinobacterial members) residing inside the host tissue, called endophyte, are widely used as agricultural bioweapons. The rhizospheric partners of plant, mycorrhizae, are also a prime agent of this chemical warfare and protect their green partners from fungal invaders and emphasize the concept of "sustainable agriculture.
Endophytes play a vital role in plant growth under biotic and abiotic stress conditions. In the p... more Endophytes play a vital role in plant growth under biotic and abiotic stress conditions. In the present investigation, a Galactose-Rich Heteropolysaccharide (GRH) with a molecular weight of 2.98 Ć 10 5 Da was isolated from endophytic Mucor sp. HELF2, a symbiont of the East Indian screw tree Helicteres isora. OVAT (One Variable at A Time) experiment coupled with RSM (Response Surface Methodology) study exhibited 1.5fold enhanced GRH production (20.10 g L -1 ) in supplemented potato dextrose broth at a pH of 7.05 after 7.5 days of fermentation in 26Ā°C. GRH has alleviated drought stress (polyethylene glycol induced) in rice seedlings (Oryza sativa ssp. indica MTU 7093 swarna) by improving its physicochemical parameters. It has been revealed that spray with a 50-ppm dosage of GRH exhibited an improvement of 1.58, 2.38, 3, and 4 times in relative water contents and fresh weight of the tissues, root length, and shoot length of the rice seedlings, respectively "in comparison to the control". Moreover, the soluble sugars, prolines, and chlorophyll contents of the treated rice seedlings were increased upto 3.5 (0.7 Ā± 0.05 mg/g fresh weight), 3.89 (0.57 Ā± 0.03 mg/g fresh weight), and 2.32 (1,119 Ā± 70.8 Ī¼g/gm of fresh weight) fold respectively, whereas malondialdehyde contents decreased up to 6 times. The enzymatic antioxidant parameters like peroxidase and superoxide dismutase and catalase activity of the 50 ppm GRH treated seedlings were found to be elevated 1.8 (720 Ā± 53 unit/gm/ min fresh weight), 1.34 (75.34 Ā± 4.8 unit/gm/min fresh weight), and up to 3 (100 ppm treatment for catalase -54.78 Ā± 2.91 unit/gm/min fresh weight) fold, respectively. In this context, the present outcomes contribute to the development of novel strategies to ameliorate drought stress and could fortify the agro-economy of India.
Endophytic entities are ubiquitous in nature with all-square bioactivity ranging from therapeutic... more Endophytic entities are ubiquitous in nature with all-square bioactivity ranging from therapeutic effects toward animals to growth promoting attributes and stress tolerance activities in case of green plants. In the present study, the club moss Lycopodium clavatum for the first time has been subjected for the isolation of endophytic fungi. An exopolysaccharide (EPS) extracted from Colletotrichum alatae LCS1, an endophytic fungi isolated from L. clavatum Linn., was characterized as a Ī²-glucan heteropolymer (composed of mannose, rhamnose, arabinose, glucose, galactose, and fucose) which plays a pivotal role in obliterating the drought stress in rice seedlings (Oryza sativa) when applied at an amount of 20, 50, and 100 ppm. The fresh weight contents of rice tissue (39%), total chlorophyll (33%), proline (41%), soluble sugar content (26%) along with antioxidant enzymes such as catalase, peroxidase, and super-oxide dismutase increased (in comparison to control of non-EPS treated seedlings) while malondialdehyde content had reduced markedly after 30 days of regular treatment. The drought resistance of rice seedling was observed at peak when applied at 50 ppm dosage. Vital parameters for EPS production like fermentation duration (5 days), medium pH (6), nutrient (carbon (glucose-7 g%/l), nitrogen (yeast extract-0.4 g%/l), and mineral (NaCl-0.10 g%/l) sources, oxygen requirements (O 2 vector or liquid alkane-n-hexane, n-heptane, n-hexadecane), and headspace volume (250 ml Erlenmeyer flask-50 ml medium, 200 ml-headspace volume) were optimized to obtain an enhanced EPS yield of 17.38 g/L-59% higher than the preoptimized one. The present study, for the first time, reported the Ī²-glucan rich heteropolysaccharide from Colletotrichum origin which is unique in structure and potent in its function of drought stress tolerance and could enhance the sustainable yield of rice cultivation in areas facing severe drought stress.
Antifungal activity of volatile and non-volatile metabolites of endophytes of Chloranthus elatior Sw
Frontiers in Plant Science
Agriculture crops that have fungal infections suffer significant economic losses and reduced crop... more Agriculture crops that have fungal infections suffer significant economic losses and reduced crop output. Chemical fungicides are used to tackle the problem, although this has additional detrimental side effects. There is an urgent need for safe and novel antifungals. Volatiles from plant-beneficial endophytic fungi are considered promising alternatives for the biological control of fungal pathogens as a sustainable approach in an agroecosystem. In the present investigation, a volatile-emitting sterile endophytic fungus, Diaporthe sp. CEL3 with bio-fumigation activity, was isolated from leaves of the ethnomedicinal plant Chloranthus elatior Sw., collected from the Passighat forest of North-East India. The camphor odor volatiles of CEL3 showed an inhibitory effect against eight fungal pathogens in vitro and minimized the infections of Monilinia fructicola, a causal agent of cherry fruit rot, in VOC-exposed cherry fruits. Rhizoctonia solani, Botrytis cinerea, Pythium ultimum, and M. f...
A biologically potent exopolysaccharide (EPS); Pestalopine was produced by Pestalotiopsis chamaer... more A biologically potent exopolysaccharide (EPS); Pestalopine was produced by Pestalotiopsis chamaeropsis CEL6, an endophytic fungal isolate of Chloranthus elatior Sw. Pestalopine is composed of glucose, arabinose, fucose, rhamnose, and galactose in a molar ratio of nearly 10:1:2:2:4 having an Mw ā¼ 3.29 x 105 Da. Pestalopine exhibited a radical scavenging effect and significantly increased antioxidant parameters (malondialdehyde, superoxide dismutase, glutathione peroxidase, reduced glutathione oxidized glutathione) in peritoneal macrophage cells in a concentration-dependent manner, with a maximum effect at 500 mg mLāā1. Pestalopine is hepatoprotective in nature and improves the liver function profiles; - total bilirubin, direct bilirubin, hepatic enzymes- alkaline phosphatase, gamma-glutamyl transferase, aspartate aminotransferase, alanine transaminase of liver fibrosis induced (through Thioacetamide) male Wistar rats in comparison to control. Pestalopine-fed rats are reported to have...
The increasing resistance of fungal pathogens against available antifungal agents is a serious th... more The increasing resistance of fungal pathogens against available antifungal agents is a serious threat to mankind. The most suitable solutions can only be found from untapped novel natural sources and endophytic metabolites are emerging as one of the dominant contributors in this field. In the present study, Ethyl acetate (EA) extract of cell-free metabolites and volatile metabolites of endophytic fungi Colletotrichum aenigma TML3 and Curvularia lunata TML9, isolated from leaves of Tropaeolum majus, exhibited broad-spectrum antifungal activity against four species of Candida and nine taxa of post-harvest phyto pathogens respectively. EA extract hampered the biofilm formation, minimised haemolytic effect, and blocked the transformation of Candida cells from yeast to hyphal form with an MFC of 200ā600 Āµg mLāā1. Central carbohydrate metabolism, ergosterol synthesis, and membrane permeability were adversely affected and caused the lethal leakage of necessary macromolecules of C. albicans...
Endophytes play a vital role in plant growth under biotic and abiotic stress conditions. In the p... more Endophytes play a vital role in plant growth under biotic and abiotic stress conditions. In the present investigation, a Galactose-Rich Heteropolysaccharide (GRH) with a molecular weight of 2.98āĆā105āDa was isolated from endophytic Mucor sp. HELF2, a symbiont of the East Indian screw tree Helicteres isora. OVAT (One Variable at A Time) experiment coupled with RSM (Response Surface Methodology) study exhibited 1.5-fold enhanced GRH production (20.10āgāLā1) in supplemented potato dextrose broth at a pH of 7.05 after 7.5ādays of fermentation in 26Ā°C. GRH has alleviated drought stress (polyethylene glycol induced) in rice seedlings (Oryza sativa ssp. indica MTU 7093 swarna) by improving its physicochemical parameters. It has been revealed that spray with a 50-ppm dosage of GRH exhibited an improvement of 1.58, 2.38, 3, and 4 times in relative water contents and fresh weight of the tissues, root length, and shoot length of the rice seedlings, respectively āin comparison to the controlā....
Endophytes are the mutualistic microorganisms that reside within the host plant and promote plant... more Endophytes are the mutualistic microorganisms that reside within the host plant and promote plant growth in adverse conditions. Plants and their endophytes are engaged in a symbiotic relationship that enables endophytes to access bioactive genes of the ethnomedicinal plants, and, as a result, endophytes are constantly addressed in the sector of pharmaceuticals and agriculture for their multidomain bio-utility. The gradual increase of antimicrobial resistance can be effectively countered by the endophytic metabolites. In these circumstances, in the present investigation, endophytic Curvularia eragrostidis HelS1 was isolated from an ethnomedicinally valuable plant Helecteris isora from East Indiaās forests. The secondary volatile and non-volatile metabolites are extracted from HelS1 and are found to be effective broad-spectrum antimicrobials. A total of 26 secondary metabolites (9 volatiles and 17 non-volatiles) are extracted from the isolate, which exhibits effective antibacterial [a...
Endophytes, being the co-evolution partners of green host plants, are factories of pharmaceutical... more Endophytes, being the co-evolution partners of green host plants, are factories of pharmaceutically valuable novel natural products. Cochliobolus sp. APS1, an endophyte of Andrographis paniculata (Green Chiretta), produces a plethora of natural bioactive compounds and the multipotent alkaloid Aziridine, 1-(2-aminoethyl)-, is the prime one among them. The isolate exhibited antibacterial, anti-biofilm, and antilarval potency. The MIC and MBC values of the ethyl-acetate culture extract ranged from 15.62 to 250 Āµg/mL against ten pathogenic microorganisms (including MRSA and VRSA). Killing kinetics data along with the leakage of macromolecules into the extracellular environment supports the cidal activity of the antibacterial principles. The broad spectrum antibacterial activity of Aziridine, 1-(2-aminoethyl)-, was optimized by a one-variable-at-a-time system coupled with response surface methodology, which led to a 45% enhancement of the antibacterial activity. The maximum response (22....
Fungal Endophytes: A Source for Biological Control Agents
Fungal Biology, 2020
Endophytic fungi are efficient biocontrol agents and offer protection to the agricultural cash cr... more Endophytic fungi are efficient biocontrol agents and offer protection to the agricultural cash crops from pest or pathogenic fungi related damage. Fungal endophyte produces a plethora of bioactive secondary metabolites with antifungal, anti-larval, insecticidal, nematicidal property and opens up new scope of myco-fumigation through volatile organic compounds to control storage pathogens, reduce post-harvest infections and increase shelf-life or facilitate safe transportation of fruits and vegetables. It is a secure way of disease control approach and a new addition to the integrated pest management system ensuring sustainable development. This chapter summarizes the bioprospecting of several potent endophytes Muscodor albus, M. vitigenus, M. roseus, M. fengyangensis, Phyllosticta capitalensis, P. paracapitalensis, Trichoderma sp., Talaromyces flavus, Acremonium sp., Lasiodiplodia theobromae, Hypoxylon investiens, Curvularia sp., Phoma sp., Penicillium sp., Nigrospora sphaerica as bio-control agents against Meloidogyne incognita, Radopholus similis, Spodoptera littoralis, Planococcus ficus, Phthorimaea operculella, etc. reducing tan spot, vascular streak, rice blast and Fusarium head blight disease, GER (Gibberella ear rot), codling and European pepper moth populations, root rot of pepper, Verticillium wilt and Ginseng pathogens, etc.
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