scholarly journals Acid Rain Increases Impact of Rice Blast on Crop Health via Inhibition of Resistance Enzymes

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 881
Author(s):  
Hong-Ru Li ◽  
Hui-Min Xiang ◽  
Jia-Wen Zhong ◽  
Xiao-Qiao Ren ◽  
Hui Wei ◽  
...  
Keyword(s):  
Acid Rain ◽  
Rice Blast ◽  
Crop Yields ◽  
Pyricularia Oryzae ◽  
Plant Pathogen Interaction ◽  
Rice Leaves ◽  
Decreasing Ph ◽  
Crop Health ◽  
Cultivation Experiment

Worldwide, rice blast (Pyricularia oryzae) causes more rice crop loss than other diseases. Acid rain has reduced crop yields globally for nearly a century. However, the effects of acid rain on rice-Pyricularia oryzae systems are still far from fully understood. In this study, we conducted a lab cultivation experiment of P. oryzae under a series of acidity conditions as well as a glasshouse cultivation experiment of rice that was inoculated with P. oryzae either before (P. + SAR) or after (SAR + P.) simulated acid rain (SAR) at pH 5.0, 4.0, 3.0 and 2.0. Our results showed that the growth and pathogenicity of P. oryzae was significantly inhibited with decreasing pH treatments in vitro culture. The SAR + P. treatment with a pH of 4.0 was associated with the highest inhibition of P. oryzae expansion. However, regardless of the inoculation time, higher-acidity rain treatments showed a decreased inhibition of P. oryzae via disease-resistance related enzymes and metabolites in rice leaves, thus increasing disease index. The combined effects of high acidity and fungal inoculation were more serious than that of either alone. This study provides novel insights into the effects of acid rain on the plant–pathogen interaction and may also serve as a guide for evaluating disease control and crop health in the context of acid rain.

In vitro evaluation of bio-agents against Pyricularia oryzae (Cav.) causing rice blast disease

2017 ◽  
Vol 37 (03) ◽  
Author(s):  
Akhilesh Kumar Kulmitra ◽  
Neha Sahu ◽  
V.B. Sanath Kumar ◽  
Thejesha A. G. ◽  
Amlan Ghosh ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Pseudomonas Fluorescens ◽  
Rice Blast ◽  
Mycelial Growth ◽  
Trichoderma Viride ◽  
Culture Technique ◽  
Pyricularia Oryzae ◽  
Blast Disease ◽  
Dual Culture

The five different bio-agents viz., Trichoderma viride, T. harzianum, T. virens, Pseudomonas fluorescens and Bacillus subtilis were evaluated against Pyricularia oryzae at four and eight days after incubation through dual culture technique. Among the five different bio-agents, highest per cent inhibition of mycelial growth of fungus was recorded in T. virens i.e. 67 per cent and 70 percent after four and eight days after incubation respectively with mean of 68.5 per cent followed by Trichoderma viride with the inhibition of 61 and 63 per cent respectively with mean of 62 per cent. The Pseudomonas fluorescens did not show any inhibition of mycelial growth of P. oryzae as the pathogen over grew the bio-agents.

In Vitro Susceptibility of Silver Nanoparticles on Thai Isolated Fungus Pyricularia oryzae from Oryza sativa L. Leaves

2017 ◽  
Vol 866 ◽  
pp. 148-151 ◽  
Author(s):  
Duongruitai Nicomrat ◽  
Wannaphan Janlapha ◽  
Nuanchan Singkran
Keyword(s):  
Silver Nanoparticles ◽  
Antimicrobial Agents ◽  
Fungal Growth ◽  
Hyphal Growth ◽  
Pyricularia Oryzae ◽  
Surface Areas ◽  
Previously Treated ◽  
Rice Leaves ◽  
Bacteria And Fungi

Silver nanoparticles (AgNPS) have been known for their effectiveness as antimicrobial agents due to their extremely large relative surface areas increases their contact with bacteria and fungi thus improving its bacteriocidal and fungicidal effectiveness. In this experiment, AgNPs were tested for antifungal activity on a rice blast fungus, Pyricuralia oryzae which is anamorph of Magnaporthe oryzae. In Vitro inhibitory property of AgNPs were observed on the fungi isolated from rice leaves and the survival isolates after AgNP treatment. The results showed AgNPs retarded and reduced the fungal growth at low concentration of 25 μg ml-1. The retarded fungi after previously treated with AgNPs gave very slower hyphal growth. The results demonstrated that AgNP can strongly inhibit the fungal growth and colony formation. AgNPs can thus be improved to be promising antifungal agents against Pyricularia oryzae with its suitable formula of AgNP in the fungicidal materials.

scholarly journals Rice Blast in Puerto Rico

1969 ◽  
Vol 62 (3) ◽  
pp. 290-300
Author(s):  
Lii-Jang Liu
Keyword(s):  
Puerto Rico ◽  
Rice Straw ◽  
Rice Blast ◽  
Mycelial Growth ◽  
Potato Dextrose Agar ◽  
Pyricularia Oryzae ◽  
In Vitro Tests ◽  
Optimum Temperature ◽  
Pathogenicity Tests

Rice blast, which had not been observed during the last six decades in Puerto Rico, reappeared recently in Manatí and in the Gurabo Substation, affecting Brazos, a cultivar introduced from Texas. Pathogenicity tests, as well as studies on the conidial morphology, showed that the fungus isolated from typical blast lesions is Pyricularia oryzae Cav. The physiology of the fungus and its sporulation on various media also were studied. The optimum temperature range, both for mycelial growth and for germination of conidia, was found to be between 24 to 28° C. Sporulation occurred satisfactorily on potato-dextrose agar enriched with coconut milk, and on steamed corn and barley, and rice-straw-decoction agars. In vitro tests with fungicides benomyl, pentachloronitrobenzene, mancozeb, chloroneb, and captan indicated that the first two compounds are the most effective in inhibiting mycelial growth of P. oryzae.

scholarly journals Investigation of Chitosan Nanoparticles Loaded with Protocatechuic Acid (PCA) for the Resistance of Pyricularia oryzae Fungus against Rice Blast

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 177 ◽  
Author(s):  
The Pham ◽  
Thi Nguyen ◽  
Thuan Thi ◽  
Thanh-Truc Nguyen ◽  
Tien Le ◽  
...  
Keyword(s):  
Rice Blast ◽  
Protocatechuic Acid ◽  
Chitosan Nanoparticles ◽  
Antimicrobial Effect ◽  
Inhibition Zone ◽  
Pyricularia Oryzae ◽  
Transmission Electron ◽  
Ft Ir ◽  
Ir Analysis

In this study, chitosan nanoparticles were used as a carrier for Protocatechuic acid (PCA) to resist Pyricularia oryzae against rice blast. The final compound was characterized using zeta potentials for its surface electricity, Fourier transform infrared (FT-IR) analysis and transmission electron microscopy (TEM) were conducted for functional groups and for particle sizes and shape, respectively. The zeta potential results showed that loading PCA causes chitosan nanoparticle (CSNP) to decrease in surface electrons. The TEM images revealed that the particle size of chitosan (CS), although increasing in size when carrying PCA molecules, showed sufficient size for reasonable penetration into fungal cells. The FT-IR analysis showed that all functional group in CSNP carried PCA matched with previous studies. The antifungal test showed that diameters of inhibition zone of CS increases significantly after loading PCA, exhibiting the strongest antimicrobial effect on the Pyricularia oryzae fungus compared with weaker effects exhibited by CSNP alone or PCA. Our results suggested that CSNP loaded with PCA could be a potential compound for eradication of Pyricularia oryzae and that further testing on in vitro rice plants is recommended to reaffirm this possibility.

scholarly journals Bacillus Cyclic Lipopeptides Iturin and Fengycin Control Rice Blast Caused by Pyricularia oryzae in Potting and Acid Sulfate Soils by Direct Antagonism and Induced Systemic Resistance

2021 ◽  
Vol 9 (7) ◽  
pp. 1441
Author(s):  
Van Bach Lam ◽  
Thibault Meyer ◽  
Anthony Arguelles Arias ◽  
Marc Ongena ◽  
Feyisara Eyiwumi Oni ◽  
...  
Keyword(s):  
Rice Blast ◽  
Induced Systemic Resistance ◽  
Pyricularia Oryzae ◽  
Blast Disease ◽  
Systemic Resistance ◽  
Acid Sulfate Soils ◽  
Acid Sulfate ◽  
Wide Range ◽  
Bacillus Spp ◽  
Sulfate Soils

Rice monoculture in acid sulfate soils (ASSs) is affected by a wide range of abiotic and biotic constraints, including rice blast caused by Pyricularia oryzae. To progress towards a more sustainable agriculture, our research aimed to screen the biocontrol potential of indigenous Bacillus spp. against blast disease by triggering induced systemic resistance (ISR) via root application and direct antagonism. Strains belonging to the B. altitudinis and B. velezensis group could protect rice against blast disease by ISR. UPLC–MS and marker gene replacement methods were used to detect cyclic lipopeptide (CLiP) production and construct CLiPs deficient mutants of B. velezensis, respectively. Here we show that the CLiPs fengycin and iturin are both needed to elicit ISR against rice blast in potting soil and ASS conditions. The CLiPs surfactin, iturin and fengycin completely suppressed P. oryzae spore germination resulting in disease severity reduction when co-applied on rice leaves. In vitro microscopic assays revealed that iturin and fengycin inhibited the mycelial growth of the fungus P. oryzae, while surfactin had no effect. The capacity of indigenous Bacillus spp. to reduce rice blast by direct and indirect antagonism in ASS conditions provides an opportunity to explore their usage for rice blast control in the field.

scholarly journals Structural Investigation and Molecular Modeling Studies of Strobilurin-Based Fungicides Active against the Rice Blast Pathogen Pyricularia oryzae

2021 ◽  
Vol 22 (7) ◽  
pp. 3731
Author(s):  
Andrea Kunova ◽  
Luca Palazzolo ◽  
Fabio Forlani ◽  
Giorgia Catinella ◽  
Loana Musso ◽  
...  
Keyword(s):  
Rice Blast ◽  
Rational Design ◽  
Structural Investigation ◽  
Resistance Mechanism ◽  
Three Dimensional ◽  
Pyricularia Oryzae ◽  
Cytochrome Bc1 ◽  
Cytochrome Bc1 Complex ◽  
Three Dimensional Model ◽  
Resistant Strains

The increasing emergence of fungicide-resistant pathogens requires urgent solutions for crop disease management. Here, we describe a structural investigation of new fungicides obtained by combining strobilurin and succinate dehydrogenase inhibitor pharmacophores. We identified compounds endowed with very good activity against wild-type Pyricularia oryzae, combined in some cases with promising activity against strobilurin-resistant strains. The first three-dimensional model of P. oryzae cytochrome bc1 complex containing azoxystrobin as a ligand was developed. The model was validated with a set of commercially available strobilurins, and it well explains both the resistance mechanism to strobilurins mediated by the mutation G143A and the activity of metyltetraprole against strobilurin-resistant strains. The obtained results shed light on the key recognition determinants of strobilurin-like derivatives in the cytochrome bc1 active site and will guide the further rational design of new fungicides able to overcome resistance caused by G143A mutation in the rice blast pathogen.

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