Inhibition Effects of Silver Nanoparticles Against Rice Blast Disease Caused by Magnaporthe Grisea

Abstract

Rice blast disease, caused by Magnaporthe grisea, is the most serious biotic threat to rice (Oryza sativa L.) production worldwide.It causes severe yield losses in Egypt especially in epidemic years. The fungus is highly variable so disease control is a challenge. In this study, the effect of silver nanoparticles (20-30 nm) against rice leaf blast fungus was evaluated under different cultivation conditions both in vitro and in vivo. Under lab conditions, the application of four concentrations of silver nanoparticles to the culture of M. grisea showed significant inhibition of both hyphal growth and number of colonies formed in a dose-dependent manner. Number of spores/ ml decreased with in all treatment. Under greenhouse conditions, Silver nanoparticles were sprayed in concentrations 0, 25, 50, 100 and 200 ppm on rice seedling leaves at three times (3 hours before inoculation, 1 and 5 days after artificial inoculation with spore suspension). Damaged Leaf Area Percentage (DLA %) indicated that the application of 100 ppm silver nanoparticles was highly efficient before and after inoculation (26.7, 15.3 and 20%), respectively compared to the untreated plants of 80%. The chemical fungicides isoprothiolane (Fuji one) and azoxystrobin (Amistar) at a concentration of 100 ppm each showed the lowest DLA (19.6 % and 14.7 %, respectively). Scanning electron microscope results revealed that the silver nanoparticles caused a detrimental effect on mycelial growth.

Trichogenic Silver-Based Nanoparticles for Suppression of Fungi Involved in Damping-Off of Cotton Seedlings

“…Because this fungus has a variety of qualities that aid with agricultural commodities, Trichodermabased products contribute to more than half of the overall worldwide biopesticide industry employed for improving plant growth, nutrient use efficiency, and physiological response to both biotic and abiotic stresses [23]. The use of green AgNPs as an antifungal agent is seen as an environmentally benign resource, an alternative to fungicides, and a cost-effective method [24,25]. Based on updated literature, the primary goals of this investigation were to: (1) determine the ability of a cell-free extract from a T. harzianum natural biocontrol strain to act as a reducing agent and stabilizer in the production of AgNPs; (2) undertake physicochemical characterization to determine the structure, size, and morphology of the generated AgNPs; and (3) test the antifungal activity of AgNPs in vitro and in vivo against three fungal pathogens, namely, R. solani, F. fujikuroi, and M. phaseolina.…”

Garlic Mediated Green Synthesis of Silver Nanoparticles as Antifungal Agents against Magnaporthe oryzae

“…The silver nanoparticles delayed and greatly inhibited fungal growth at low concentrations, according to radial growth measurements. 61 found that secondary metabolites extracted from C. elatum showed antifungal activity against P. oryzae with an ED 50 of 231ppm. 62 Conidia Germination Inhibition: Because fungi need a large number of germinated conidia to successfully infect plant tissue, inhibiting conidia germination is critical in reducing or preventing the formation of plant diseases.…”

Using Gamma Rays for Genetic Improvement of Rice Resistance to Blast Disease

“…Rice blast is the most serious fungal diseases in Egypt. It is caused by Magnaporthe oryzae (Elamawi and El-shafey, 2013;Hassan et al, 2017). The asexual stage of this fungus is named Pyricularia oryzae (TeBeest et al, 2012) which is the only form that is mostly present in the field (Picco et al, 2001;Elamawi and El-shafey, 2013).…”

“…It is caused by Magnaporthe oryzae (Elamawi and El-shafey, 2013;Hassan et al, 2017). The asexual stage of this fungus is named Pyricularia oryzae (TeBeest et al, 2012) which is the only form that is mostly present in the field (Picco et al, 2001;Elamawi and El-shafey, 2013). This form can infect all aerial parts of rice plant resulting in yield losses of over 50% in susceptible cultivars under favorable conditions (Dean et al, 2005;Wilson et al, 2009;Singh et al, 2015).…”