Nanotechnology can offer green and eco-friendly alternatives for plant disease management. Apart from being eco-friendly, fungi are used as bio-manufacturing units, which will provide an added benefit in being easy to use, as compared to other microbes. The non-pathogenic nature of some fungal species in combination with the simplicity of production and handling will improve the mass production of silver nanoparticles. Recently, a diverse range of fungi have been screened for their ability to create silver nanoparticles. Mycosynthesis of gold, silver, gold-silver alloy, selenium, tellurium, platinum, palladium, silica, titania, zirconia, quantum dots, usnic acid, magnetite, cadmium telluride and uraninite nanoparticles has also been reported by various researchers. Nanotechnological application in plant pathology is still in the early stages. For example, nanofungicides, nanopesticides and nanoherbicides are being used extensively in agriculture practices. Remote activation and monitoring of intelligent nano-delivery systems can assist agricultural growers of the future to minimize fungicides and pesticides use. Nanoparticle-mediated gene transfer would be useful for improvement of crops resistant to pathogens and pest. This review critically assesses the role of fungi in the synthesis of nanoparticles, the mechanism involved in the synthesis, the effect of different factors on the reduction of metal ions in developing low-cost techniques for the synthesis and recovery of nanoparticles. Moreover, the application of nanoparticles in plant disease control, antimicrobial mechanisms, and nanotoxicity on plant ecosystem and soil microbial communities has also been discussed in detail.

Myconanoparticles: synthesis and their role in phytopathogens management

Nanotechnology can offer green and eco-friendly alternatives for plant disease management. Apart from being eco-friendly, fungi are used as bio-manufacturing units, which will provide an added benefit in being easy to use, as compared to other microbes. The non-pathogenic nature of some fungal species in combination with the simplicity of production and handling will improve the mass production of silver nanoparticles. Recently, a diverse range of fungi have been screened for their ability to create silver nanoparticles. Mycosynthesis of gold, silver, gold–silver alloy, selenium, tellurium, platinum, palladium, silica, titania, zirconia, quantum dots, usnic acid, magnetite, cadmium telluride and uraninite nanoparticles has also been reported by various researchers. Nanotechnological application in plant pathology is still in the early stages. For example, nanofungicides, nanopesticides and nanoherbicides are being used extensively in agriculture practices. Remote activation and monitoring of intelligent nano-delivery systems can assist agricultural growers of the future to minimize fungicides and pesticides use. Nanoparticle-mediated gene transfer would be useful for improvement of crops resistant to pathogens and pest. This review critically assesses the role of fungi in the synthesis of nanoparticles, the mechanism involved in the synthesis, the effect of different factors on the reduction of metal ions in developing low-cost techniques for the synthesis and recovery of nanoparticles. Moreover, the application of nanoparticles in plant disease control, antimicrobial mechanisms, and nanotoxicity on plant ecosystem and soil microbial communities has also been discussed in detail.

ARTICLE; AGRICULTURE AND ENVIRONMENTAL BIOTECHNOLOGY Myconanoparticles: synthesis and their role in phytopathogens management

Quorum sensing (QS) is a chemical communication process that Pseudomonas aeruginosa uses to regulate virulence and biofilm formation. Disabling of QS is an emerging approach for combating its pathogenicity. Silver nanoparticles (AgNPs) have been widely applied as antimicrobial agents against human pathogenic bacteria and fungi, but not for the attenuation of bacterial QS. Here we mycofabricated AgNPs (mfAgNPs) using metabolites of soil fungus Rhizopus arrhizus BRS-07 and tested their effect on QS-regulated virulence and biofilm formation of P. aeruginosa. Transcriptional studies demonstrated that mfAgNPs reduced the levels of LasIR-RhlIR. Treatment of mfAgNPs inhibited biofilm formation, production of several virulence factors (e.g. LasA protease, LasB elastrase, pyocyanin, pyoverdin, pyochelin, rhamnolipid, and alginate) and reduced AHLs production. Further genes quantification analyses revealed that mfAgNPs significantly down-regulated QS-regulated genes, specifically those encoded to the secretion of virulence factors. The results clearly indicated the anti-virulence property of mfAgNPs by inhibiting P. aeruginosa QS signaling.

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Mycofabricated biosilver nanoparticles interrupt Pseudomonas aeruginosa quorum sensing systems.

Development of reliable and low-cost requirement for large-scale eco-friendly biogenic synthesis of metallic nanoparticles is an important step for industrial applications of bionanotechnology. In the present study, the mycosynthesis of spherical nano-Ag (12.7 ± 0.8 nm) from extracellular filtrate of local endophytic T. harzianum SYA.F4 strain which have interested mixed bioactive metabolites (alkaloids, flavonoids, tannins, phenols, nitrate reductase (320 nmol/hr/ml), carbohydrate (25 μg/μl) and total protein concentration (2.5 g/l) was reported. Industrial mycosynthesis of nano-Ag can be induced with different characters depending on the fungal cultivation and physical conditions. Taguchi design was applied to improve the physicochemical conditions for nano-Ag production, and the optimum conditions which increased its mass weight 3 times larger than a basal condition were as follows: AgNO3 (0.01 M), diluted reductant (10 v/v, pH 5) and incubated at 30 °C, 200 rpm for 24 hr. Kinetic conversion rates in submerged batch cultivation in 7 L stirred tank bioreactor on using semi-defined cultivation medium was as follows: the maximum biomass production (Xmax) and maximum nano-Ag mass weight (Pmax) calculated (60.5 g/l and 78.4 g/l respectively). The best nano-Ag concentration that formed large inhibition zones was 100 μg/ml which showed against A.alternate (43 mm) followed by Helminthosporium sp. (35 mm), Botrytis sp. (32 mm) and P. arenaria (28 mm).

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Applying Taguchi design and large-scale strategy for mycosynthesis of nano-silver from endophytic Trichoderma harzianum SYA.F4 and its application against phytopathogens.

Green synthesis of nanoparticles has an increasing benefit because of the rising need for developing environmentally friendly, cost-effective and safe strategies for nanomaterials synthesis. In this study, we investigated the fungus Trichoderma viride, which is used for the synthesis of biogenic silver nanoparticles. The bioreduction of silver nanoparticles (Ag NPs) was observed spectrophotometrically, and the studied Ag NPs were characterized by ultraviolet–visible spectroscopy (UV–Vis), transmission electron microscopy and scanning electron microscopy. The Ag NPs synthesized by T. viride were observed as stabilized and polydispersed globular particles, in sizes ranging from 1 to 50 nm. The antibacterial potential of Ag NPs was evaluated against human pathogenic bacteria. The biogenic Ag NPs significantly inhibited the growth of all tested pathogenic bacteria.

https://tandfonline.com/doi/pdf/10.1080/13102818.2015.1133255

Antimicrobial activity and green synthesis of silver nanoparticles using Trichoderma viride

A total of 75 isolates belonging to five different species of Trichoderma viz., T. asperellum, T. harzianum, T. longibrachiatum, T. pseudokoningii and T. virens were screened for the production of silver nanoparticles. Although all the isolates produced nanoparticles, T. virens VN-11 could produce maximum nanoparticles as evident from the UV-Vis study. The highest Plasmon band was observed at 420 nm at every 24 h that attained maximum intensity at 120 h (0.543). The high resolution transmission electron microscopy (HRTEM) further provided the morphology of the nanoparticles. These nanoparticles were found single or aggregated with round and uniform in shape and 8-60 nm in size. The nitrate reductase activity of VN-11 was found to be 150 nmol/h/mL which confirmed the production of silver nanoparticles through reduction of Ag+ to Ag0.

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Biosynthesis of silver nanoparticles from Trichoderma species.

Lentil (Lens culinaris Medik) ranks third in the world after chickpea and pea (FAO 2015). It is considered as one of the oldest domesticated crop in the Near East based on the archaeological evidence (Cubero, 1981; Zohary and Hopf, 1973) and is grown as an important food source over the last 8,000 years (Dhuppar et al., 2012; Oplinger et al., 1990). Lentil is an annual, autogamous, diploid crop (2n=14) with genome size of approximately 4 Gbp in its haploid component (Arumuganathan and Earle, 1991). Lentil is planted as rotational crop for deriving ecological and environment benefits by improving rhizosphere diversity through biological nitrogen fixation increase in fertility of soil, carbon sequestration, and by management of diseases, weeds and insect pests (Kumar et al., 2013). It is an economical source of proteins, carbohydrates, minerals and fiber for resource poor. The major lentil producing countries are Australia, North America, Western Asia, the Middle East, Nepal, China, Ethiopia, Syria, Bangladesh and India (FAOSTAT, 2014). In India, main lentil growing states are Madhya Pradesh, Bundelkhand region of Uttar Pradesh and Bihar. The global cultivated area of lentil is International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 6 Number 11 (2017) pp. 2533-2541 Journal homepage: http://www.ijcmas.com

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Screening of Lentil (Lens culinaris Medikus sub sp. culinaris) Germplasm against Fusarium Wilt (Fusarium oxysporum f. sp. lentis)

The worldwide 1.5 million fungal species were identified and among them around 10% have been discovered and described. Out of 10%, only1% fungal species has been examined for secondary metabolites based on characterization (Weber et al., 2007). The Trichoderma species has various features that could helpful for researcher’s community. Amidst these diverse characteristics, which involved in production of abundant secondary metabolite compounds and some compounds are known function and rest of compounds often have vague or unidentified its functions in the organism and which are significant importance to humankind in a different field such as agricultural applications, industrial and medical. The fungus produced certain volatile compounds and these volatile International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 6 Number 5 (2017) pp. 1105-1123 Journal homepage: http://www.ijcmas.com

Secondary Metabolites Approach to Study the Bio-Efficacy of Trichoderma asperellum Isolates in India

The study of morphology and bioefficacy of Trichoderma was undertaken to select the effective isolates against soil-borne pathogens. Fifty one (51) isolates (23 isolates of Trichoderma virens and 28 isolates of Trichoderma harzianum) were morphologically characterised based on the growth characteristics on PDA medium, the size and shape of phialides and conidia.These isolates were screened for bioefficacy against soil borne plant pathogens (Fusarium oxysporum, Rhizoctonia solani and Sclerotium rolfsii) based on their percent inhibition observed during dual culture, volatile and non-volatile methods. Eight T. virens isolates and 12 T. harzianum isolates were proven to be potential isolates against the soil-borne pathogens tested. No correlation was found between bioefficacy and morphology in both species isolates.

	Key words: Trichoderma virens, Trichoderma harzianum, morphology, dual culture, biocontrol and bioefficacy.

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Bioefficacy of Trichoderma isolates against soil-borne pathogens

Out of eight isolates of T. virens, three (V-7, V-19 and V-21) showed high and one (V-4) lowest per cent inhibition. Similarly, three isolates of T. harzianum, (H-10, H-12 and H-21) showed high per cent inhibition and one isolate (H-6) showed lowest per cent inhibition against F. oxysporum, R. solani and S. rolfsii. About 53 major antifungal compounds from T. virens (4 isolates) and about 86 major antifungal compounds from T. harzianum (4 isolates) were identified from GCMS analysis with hexane fractions. Among eight isolates, only H-10 produces 13 while and V-19 produced 6 major antimicrobial compounds. Therefore, these isolates may be considered as biocontrol agents against soilborne plant pathogens.

N. Srinivasa

Papers

Biosynthesis of silver nanoparticles from Trichoderma species.

Screening of Lentil (Lens culinaris Medikus sub sp. culinaris) Germplasm against Fusarium Wilt (Fusarium oxysporum f. sp. lentis)

Secondary Metabolites Approach to Study the Bio-Efficacy of Trichoderma asperellum Isolates in India

Bioefficacy of Trichoderma isolates against soil-borne pathogens

Separation and identification of antifungal compounds from Trichoderma species BY GC-MS and their bio-efficacy against soil-borne pathogens.