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Chickpea (Cicer arietinum L.) is one of the main pulse crops of Pakistan. The yield of chickpea is affected by a variety of biotic and abiotic factors. Due to their environmentally friendly nature, different nanoparticles are being synthesized and applied to economically important crops. In the present study, Trichoderma harzianum has been used as a stabilizing and reducing agent for the mycosynthesis of zinc oxide nanoparticles (ZnO NPs). Before their application to control Fusarium wilt of chickpea, synthesized ZnO NPs were characterized. X-ray diffraction (XRD) analysis revealed the average size (13 nm) of ZnO NPs. Scanning electron microscopy (SEM) indicated their spherical structure, and energy dispersive X-ray analysis (EDX) confirmed the oxide formation of ZnO NPs. Transmission electron microscopy (TEM) described the size and shape of nanoparticles, and Fourier transform infrared (FTIR) spectroscopy displayed the presence of reducing and stabilizing chemical compounds (alcohol, carboxylic acid, amines, and alkyl halide). Successfully characterized ZnO NPs exhibited significant mycelial growth inhibition of Fusarium oxysporum, in vitro. In a greenhouse pot experiment, the priming of chickpea seeds with ZnO NPs significantly increased the antioxidant activity of germinated plants and they displayed 90% less disease incidence than the control. Seed priming with ZnO NPs helped plants to accumulate higher quantities of sugars, phenol, total proteins, and superoxide dismutase (SOD) to create resistance against wilt pathogen. These nanofungicides were produced in powder form and they can easily be transferred and used in the field to control Fusarium wilt of chickpea. [ABSTRACT FROM AUTHOR]

Silver nanoparticle (AgNP) production and their use as antimicrobial agents is a current area of active research. Biosynthesis is the most sustainable production method, and fungi have become candidates of interest in AgNP production. However, investigations into the physiological responses of fungi due to silver exposure are scanty. This present work utilized two strains of Saccharomyces cerevisiae (one used in commercial fermentation and a naturally occurring strain) to determine the physiological consequences of their transient exposure to AgNO3. The assessments were based on studies involving growth curves, minimal inhibitory concentration assays, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) imaging, and inductively coupled plasma optical emission spectroscopy (ICP-OES). Results indicated (a) the capability of S. cerevisiae to produce silver nanoparticles, even at elevated levels of exposure; (b) strain origin had no significant impact on S. cerevisiae physiological response to AgNO3; and (c) coexposure to copper and silver significantly increased intracellular copper, silver, and calcium in treated yeast cells. In addition, electron microscopy and ICP-OES results revealed that both strains internalized silver after exposure, resulting in the shrunken and distorted physical appearance visible on SEM micrographs of treated cells. Though a promising candidate for AgNPs biosynthesis, this study analyzed the effects of transient silver exposure on S. cerevisiae growth physiology and morphology. [ABSTRACT FROM AUTHOR]

Silver nanoparticle (AgNP) production and their use as antimicrobial agents is a current area of active research. Biosynthesis is the most sustainable production method, and fungi have become candidates of interest in AgNP production. However, investigations into the physiological responses of fungi due to silver exposure are scanty. This present work utilized two strains of Saccharomyces cerevisiae (one used in commercial fermentation and a naturally occurring strain) to determine the physiological consequences of their transient exposure to AgNO3. The assessments were based on studies involving growth curves, minimal inhibitory concentration assays, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) imaging, and inductively coupled plasma optical emission spectroscopy (ICP-OES). Results indicated (a) the capability of S. cerevisiae to produce silver nanoparticles, even at elevated levels of exposure; (b) strain origin had no significant impact on S. cerevisiae physiological response to AgNO3; and (c) coexposure to copper and silver significantly increased intracellular copper, silver, and calcium in treated yeast cells. In addition, electron microscopy and ICP-OES results revealed that both strains internalized silver after exposure, resulting in the shrunken and distorted physical appearance visible on SEM micrographs of treated cells. Though a promising candidate for AgNPs biosynthesis, this study analyzed the effects of transient silver exposure on S. cerevisiae growth physiology and morphology.