Induction of defence response in Oryza sativa L. against Rhizoctonia solani (Kuhn) by chitosan nanoparticles (original) (raw)
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Nature friendly solution for rice sheath blight caused by Rhizoctonia solani Kuhn
2022
By considering the major upcoming disease in rice growing areas, that is sheath blight in rice, caused by Rhizoctonia solani Kuhn and the huge chemicals used in rice production, including disease management, research was carried out at the College of Agriculture, V. C. Farm, Mandya, during Kharif 2020-21, in order to develop a new non-chemical strategy for managing the sheath blight disease in rice. A total of six bioagents were tested in vitro by using the dual culture technique, out of which Trichoderma harzianum showed the highest mycelial inhibition (60.37%), followed by Pseudomonas fluorescens (54.4%) and the least effective was T. asperullum (37.44%). Another in vitro study was done to test different plant extracts by using a poisoned food technique against R. solani at 1, 5, 10 and 20% concentrations. Seaweed extract (75.5%) and garlic extract (65.13%) were found to be the most effective in controlling pathogen growth. Then field experiment was carried out during Kharif 2020 with the most effective treatments of in vitro studies along with the biodegradable polymer chitosan and nano silicon. Out of all the treatments, most effective treatments with mean least mean disease severity were chitosan (12.50%) and nano silicon (14.79%) when compared to the chemical hexaconazole 5 EC (13.89%) which was used as a positive control and the least effective treatment was seaweed extract (20.41%), followed by T. viride (19.0%), whereas the untreated control showed 28.73% mean disease severity. In addition to the reduction in disease, these treatments also contribute to the growth and yield of the crop. Maximum grain yield and high Benefit cost ratio was recorded in the chitosan treatment (5350 kg/ha & 2.49) when compared to the hexaconazole (5157 kg/ha & 2.35), followed by nano silicon (4666.6 kg/ha & 2.31) and the least was seaweed @ 0.2% (4082.5 kg/ha & 2.08) followed by P. fluorescens (4015.83 kg/ha & 2.06) when compared to control (3125.0 kg/ha and 1.34).
2024
Paddy is the second crop where huge amounts of chemicals are used for production, majorly for disease control. To avoid excess use of chemicals in the rice fields and also to find the best alternative solution to fungicides for sheath blight disease caused by Rhizoctonia solani, research was carried out by using various bioagents, plant extracts and synthetic bio-polymers. Prior to the field experiments, in vitro studies were carried out to check the efficacy of various bio agents and plant extracts by using dual culture and poisoned food techniques, respectively. Trichoderma harzianum showed the highest mycelial growth inhibition (60.37%), followed by Pseudomonas fluorescens (54.4%), and the least effective was showed by T. asperellum (37.44%). The field experiments were carried out in Kharif 2019-20 and 2020-21, to test the fruitfulness of in vitro studies along with some biopolymers. In Kharif 2019-20 out of all the treatments, effective treatment with least mean disease severity was observed in chitosan (12.50%) and nano silicon (14.79%) application when compared to the fungicide hexaconazole 5 EC (13.89%) which was used as a positive control and the least effective treatment was observed in seaweed extract (18.81%), followed by T. viride (19.0%) whereas, the untreated control showed 28.73% of disease severity. In Kharif 2020-21 chitosan (18.77%) and nano silicon (23.95%) treatments were effective when compared to the hexaconazole 5 EC (23.21%) and highest disease severity was observed in seaweed extract (37.0 %), followed by T. viride (34.81%), whereas the untreated control showed 51.6 % of mean disease severity.
Scientific Reports, 2021
Reduced pathogen resistance and management of the left-over rice stubble are among the most important challenges faced in rice cultivation. A novel and eco-friendly strategy to synthesise ‘Fungal Chitosan’ (FC) from Aspergillus niger using rice straw could serve as a sustainable treatment approach to improve both disease resistance and yields, while also effectively managing the rice stubble waste. The FC treatment promoted germination as well as growth parameters in rice varieties, TN1 (high yielding-susceptible) and PTB33 (low yielding-resistant) better than a commercial chitosan (PC). Treatments of exogenously applied FC to plants produced direct toxicity to Xoo, and reduced the BLB disease index by 39.9% in TN1. The capability of FC to trigger a cascade of defense pathways was evident from the measurable changes in the kinetics of defense enzymes, peroxidase (POD) and polyphenol oxidase (PPO). FC treatment increased levels of POD in TN1 by 59.4%, which was 35.3% greater than tha...
Biotechnology Letters, 2012
The antifungal properties and mechanism of three types of chitosan against the rice sheath blight pathogen, Rhizoctonia solani, were evaluated. Each chitosan had strong antifungal activity against R. solani and protected rice seedlings from sheath blight, in particular, two types of acid-soluble chitosan caused a 60-91 % inhibition in mycelial growth, 31-84 % inhibition of disease incidence, and 66-91 % inhibition in lesion length. The mechanism of chitosan in protection of rice from R. solani pathogen was attributed to direct destruction of the mycelium, evidenced by scanning and transmission electron microscopic observations and pathogenicity testing; indirect induced resistance was evidenced by the changes in the activities of the defense-related phenylalanine ammonia lyase, peroxidase and polyphenol oxidase in rice seedling. To our knowledge, this is the first report on the antifungal activity of chitosan against rice R. solani.
Four new fungicidal formulations, viz. tebuconazole 50% + trifloxystrobin 25% WG, difenoconazole 25% SC, propiconazole 13.9% + difenconazole 13.9% EC and kresoxim methyl 44.3% SC were evaluated against Rhizoctonia solani Kuhn of rice (Oryza sativa L.) in vitro and under field conditions during kharif 2016 and 2017. In vitro growth inhibition tests revealed that the EC 50 values of tebuconazole 50% + trifloxystrobin 25% WG, difenoconazole 25% SC, propiconazole 13.9% + difenconazole 13.9% EC and kresoxim methyl 44.3% SC against R. solani ranged from 0.398 to 42.35 ppm a.i., whereas the corresponding EC 90 values were 8.92 to more than 2000 ppm a.i. Tebuconazole 50% + trifloxystrobin 25% WG was most inhibitory to mycelial growth of the fungus with EC 50 and EC 90 values of 0.39 and 8.92 ppm a.i. followed by propiconazole 13.9% + difenconazole 13.9% EC. Tebuconazole 50% + trifloxystrobin 25% WG and propiconazole 13.9% + difenconazole 13.9% EC completely inhibited the sclerotia formation at 2.5 ppm and 25 ppm a.i., respectively. In field trials, tebuconazole 50% + trifloxystrobin 25% WG sprayed at 0.4 and 0.8 g/l proved most effective and suppressed sheath blight severity by 50.98 and 79.12%, respectively along with enhancing grain yield of rice followed by propiconazole 13.9% + difenconazole 13.9% EC. However, kresoxim methyl 44.3% SC was the least effective fungicide. Based on bioefficacy and benefit-cost ratio, spray application of tebuconazole 50% + trifloxystrobin 25% WG at 0.4 g/l and propiconazole 13.9% + difenconazole 13.9% EC at 2 ml/l were found highly economical in managing sheath blight of rice with a benefit-cost of 3.52 and 3.02, respectively. Post harvest residues analysis of tebuconazole 50% + trifloxystrobin 25% WG, propiconazole 13.9% + difenconazole 13.9% EC and difenoconazole 25% SC were found below limit of quantification, i.e. 0.01 ppm in rice grains, cropped soil, paddy straw and husk at their single/recommended and double of the recommended doses indicating that tebuconazole 50% + trifloxystrobin 25% WG at 0.4 g/l and propiconazole 13.9% + difenconazole 13.9% EC were safe from the human, animals and environmental point of view.
Efficiency of Selected Fungicides on Blast and Blight of Rice Leaves
Asian Journal of Advances in Agricultural Research, 2017
The effect of pathogens on grains is closely related to the severity of the disease on plants. Similarly, infection of leaves is very important in epidemic of blast and blight. The objective of this study was to develop a treatment program suitable for different fungicides to protect the leaves of rice plants throughout the vegetative phase against blast and leaf blight by determining the required dose and the duration of protection for each fungicide. The results showed that Pyricularia oryzae was drastically inhibited on the leaves of rice at 300 ppm combined dose of Carboxin + Thiram, whereas Helminthosporium oryzae was completely inhibited at a dose of 750 ppm with the same fungicide combination. However, this product caused a total leaf yellowing and requires repeated applications So it is not recommended. Pyrazophos has no effect on Helminthosporium oryzae even at very high doses. However, this product completely inhibited Pyricularia oryzae at a dose of 750 ppm per an experimental unit. To protect against rice leaf blast throughout the vegetative phase, the product should be applied every two weeks. On the other hand, the 750 ppm Tricyclazole totally
Evaluation of new fungicide against sheath blight (R. solani) of Rice
Journal of Pharmacognosy and Phytochemistry, 2018
Rice sheath blight, caused by the fungal pathogen Rhizoctonia solani Kuhn [Sexual stage: Thanetophorus cucumeris (Frank) Donk] is one of the major production constraints in rice-growing countries of the world. Under conditions favoring disease, up to 50% of grain yield may be lost (Marchetti and Bollich 1991). Control may be achieved with fungicides (Groth 2008), but cost and the potential for development of pathogen resistance make plant genetic resistance preferable. Plants can be induced locally and systemically to become more resistant to diseases through various biotic or abiotic stresses. The best characterized signal pathway for systemically induced resistance is SAR (systemic acquired resistance) that is activated by localized infections with necrotizing pathogens. It is characterized by protection against a broad range of pathogens, by a set of induced proteins and by its dependence on salicylic acid (SA) Various chemicals have been discovered that seem to act at various po...
Efficacy of fungicides for the management of Sheath Blight of rice
Sheath Blight of rice caused by Rhizoctonia solani (teleomorph:Thanatephorus cucumeris), is a notorious pathogen and has a wide host range with worldwide in distribution, a very destructive disease under favorable weather conditions in rice growing areas of the world which ultimately causes substantial yield losses. Field experiment were laid out during the kharif season 2016-2017 at N.E. Borlaug Crop Research Centre, Pantnagar (290 N latitude, 79.30 E longitude), Uttarakhand on rice cultivar Pant Dhan- 4 to evaluate the effect of different fungicides in controlling sheath blight of rice. Seven fungicides viz; sheath mark (validamycin 3% L), Tilt (propiconazole 25 % EC), Beam (tricyclazole 75% WP), Folicur (tebuconazole 16%L), Contaf (hexaconazole 5% EC), Bavistin (carbendazim 50% WP) and Amistar (azoxystrobin 23% SC) were evaluated for the control of the pathogen at different stages of the plant growth while the control plots were left un-treated. Among these seven fungicides, azoxystrobin 23 % SC showed minimum disease severity (41.06 %) with 46.03 per cent disease control over check followed by Tilt (propiconazole 25% EC) (45.76 %) with 41.37 per cent disease control over check as compared to control with disease severity (80.97 %) along with maximum yield (69.93q/ha) and (67.72q/ha) respectively. Among fungicides tested. In vitro, Azoxystrobin 23% SC was found most effective and showed 100 per cent inhibition of mycelial growth of R.solani, from 25 ppm. This study showed that, Azoxystrobin 23% SC a new generation fungicide is more effective and increases the yield upto 22.42 percent.
Environmental monitoring and assessment, 2018
Rice is a staple food for about 65% of the India's population. India ranks first in area under rice and second in production of rice in the world. In India, it is cultivated over 43.39 m ha with a production and productivity of 104.32 million tons and 2404 kg/ha, respectively. Besides ensuring food security of the nation, it is an export commodity and earns a huge foreign exchange. In this study, we investigated the efficacy of five fungicides against Rhizoctonia solani Kuhn AG-1 IA, inciting sheath blight of rice in vitro and under field conditions along with post-harvest residue of the fungicides found effective in disease management. In vitro growth inhibition tests revealed that the EC values of azoxystrobin 18.2% + difenoconazole 11.4% SC, pencycuron 22.9% SC, thifluzamide 23.9% SC, hexaconazole 4% + zineb 68% WP, and validamycin 3% L against Rhizoctonia solani ranged from 0.006 to 354.81 ppm a.i., whereas the corresponding EC values were 0.758 to 1202.26 ppm a.i. Thifluzam...