scholarly journals The antagonistic mechanism of Bacillus velezensis ZW10 against rice blast disease: Evaluation of ZW10 as a potential biopesticide

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256807
Author(s):  
Zuo Chen ◽  
Lu Zhao ◽  
Yilun Dong ◽  
Wenqian Chen ◽  
Chunliu Li ◽  
...  
Keyword(s):  
Rice Blast ◽  
Early Stage ◽  
Defense Responses ◽  
Blast Disease ◽  
Rice Grain ◽  
Bacillus Velezensis ◽  
Control Effect ◽  
Control Activity ◽  
Antifungal Substances

Rice blast, caused by the fungus Magnaporthe oryzae, is one of the three major diseases affecting rice production and quality; it reduces rice grain yield by nearly 30%. In the early stage of this study, a strain of Bacillus velezensis with strong inhibition of M. oryzae was isolated and named ZW10. In vitro assays indicated prolonged germination time of conidia of M. oryzae treated with the antifungal substances of ZW10, 78% of the conidia could not form appressorium, and the conidial tubes expanded to form vacuolar structure and then shrank. The results of FDA-PI composite dyes showed that the antifungal substances of ZW10 inhibited the normal activity of M. oryzae hyphae that were rarely able to infect the epidermal cells of rice leaf sheath in vivo tests. In addition, rice treated with the antifungal substances of ZW10 showed a variety of defense responses, including activation of defense-related enzymes, increased expression of the salicylic acid pathway genes, and accumulation of hydrogen peroxide (H2O2), which might function directly or indirectly in resistance to pathogen attack. The field experiment with rice blast infection in different periods showed that the antifungal substances of ZW10 had the same control effect as carbendazim. The significant biological control activity of ZW10 and its capacity to stimulate host defenses suggest that this B. velezensis strain has the potential to be developed into a biopesticide for the biocontrol of rice blast.

scholarly journals Long Non-coding RNAs Responsive to Blast Fungus Infection in Rice

Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Lan-Lan Wang ◽  
Jing-Jing Jin ◽  
Li-Hua Li ◽  
Shao-Hong Qu
Keyword(s):  
Rice Blast ◽  
Blast Resistance ◽  
Enrichment Analysis ◽  
Defense Responses ◽  
Pathogen Resistance ◽  
Blast Disease ◽  
Fungus Infection ◽  
Blast Fungus ◽  
Gene Transcription Level ◽  
Non Coding Rnas

Abstract Background Long non-coding RNAs (LncRNAs) have emerged as important regulators in many physiological processes in plant. By high-throughput RNA-sequencing, many pathogen-associated LncRNAs were mapped in various plants, and some of them were proved to be involved in plant defense responses. The rice blast disease caused by Magnaporthe oryzae (M. oryzae) is one of the most destructive diseases in rice. However, M. oryzae-induced LncRNAs in rice is yet to be studied. Findings We investigated rice LncRNAs that were associated with the rice blast fungus. Totally 83 LncRNAs were up-regulated after blast fungus infection and 78 were down-regulated. Of them, the natural antisense transcripts (NATs) were the most abundant. The expression of some LncRNAs has similar pattern with their host genes or neighboring genes, suggesting a cis function of them in regulating gene transcription level. The deferentially expressed (DE) LncRNAs and genes co-expression analysis revealed some LncRNAs were associated with genes known to be involved in pathogen resistance, and these genes were enriched in terpenoid biosynthesis and defense response by Gene Ontology (GO) enrichment analysis. Interestingly, one of up-regulated DE-intronic RNA was derived from a jasmonate (JA) biosynthetic gene, lipoxygenase RLL (LOX-RLL). Levels of JAs were significantly increased after blast fungus infection. Given that JA is known to regulate blast resistance in rice, we suggested that LncRNA may be involved in JA-mediated rice resistance to blast fungus. Conclusions This study identified blast fungus-responsive LncRNAs in rice, which provides another layer of candidates that regulate rice and blast fungus interactions.

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.

scholarly journals Structural basis of pathogen recognition by an integrated HMA domain in a plant NLR immune receptor

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
A Maqbool ◽  
H Saitoh ◽  
M Franceschetti ◽  
CEM Stevenson ◽  
A Uemura ◽  
...  
Keyword(s):  
Nicotiana Benthamiana ◽  
Rice Blast ◽  
Plant Pathogens ◽  
Rice Cultivar ◽  
Blast Disease ◽  
Structural Basis ◽  
Immune Receptor ◽  
Immune Receptors ◽  
Direct Recognition

Plants have evolved intracellular immune receptors to detect pathogen proteins known as effectors. How these immune receptors detect effectors remains poorly understood. Here we describe the structural basis for direct recognition of AVR-Pik, an effector from the rice blast pathogen, by the rice intracellular NLR immune receptor Pik. AVR-PikD binds a dimer of the Pikp-1 HMA integrated domain with nanomolar affinity. The crystal structure of the Pikp-HMA/AVR-PikD complex enabled design of mutations to alter protein interaction in yeast and in vitro, and perturb effector-mediated response both in a rice cultivar containing Pikp and upon expression of AVR-PikD and Pikp in the model plant Nicotiana benthamiana. These data reveal the molecular details of a recognition event, mediated by a novel integrated domain in an NLR, which initiates a plant immune response and resistance to rice blast disease. Such studies underpin novel opportunities for engineering disease resistance to plant pathogens in staple food crops.

scholarly journals PAF104, a Synthetic Peptide to Control Rice Blast Disease by Blocking Appressorium Formation in Magnaporthe oryzae

2013 ◽  
Vol 26 (12) ◽  
pp. 1407-1416 ◽  
Author(s):  
Aarón Rebollar ◽  
Belén López-García
Keyword(s):  
Magnaporthe Oryzae ◽  
Synthetic Peptide ◽  
Rice Blast ◽  
Surface Protein ◽  
Inhibitory Effect ◽  
Rice Blast Disease ◽  
Blast Disease ◽  
Appressorium Formation ◽  
Hydrophobic Surfaces

Magnaporthe oryzae is the most devastating pathogen of rice and the main cause of crop losses worldwide. The successful management of blast disease caused by this fungus is a clear necessity. The synthetic peptide PAF104 has been characterized by its inhibition of M. oryzae appressorium formation on hydrophobic surfaces. Growth and the ability of conidia to germinate was not affected by PAF104, indicating the lack of toxicity on fungal conidia. The addition of the cutin monomer 1,16-hexadecanediol does not interfere with the inhibitory effect of PAF104 on in vitro hydrophobic surfaces. On the other hand, inhibition of appressorium formation by PAF104 was nullified by the exogenous addition of cAMP. Our results suggest that PAF104 affects the Pmk1 pathway by repression of the gene expression of MoMSB2, which encodes a sensing surface protein, and the mitogen-activated protein/extracellular signal-regulated kinase kinase kinase MST11. The pathogenicity of M. oryzae was reduced after PAF104 treatment specifically blocking appressorium formation. Our results support PAF104 as a promising compound to control rice blast disease by blocking a specific target related to appressorium formation, a process essential for infection of rice leaves. Moreover, PAF104 is proposed as a lead compound to develop novel specific fungicides with improved properties.

scholarly journals Long non-coding RNAs responsive to blast fungus infection in rice

2020 ◽  
Author(s):  
Lanlan Wang ◽  
Jing-Jing Jin ◽  
Li-Hua Li ◽  
Shao-Hong Qu
Keyword(s):  
Rice Blast ◽  
Blast Resistance ◽  
Enrichment Analysis ◽  
Defense Responses ◽  
Pathogen Resistance ◽  
Blast Disease ◽  
Fungus Infection ◽  
Blast Fungus ◽  
Gene Transcription Level ◽  
Non Coding Rnas

Abstract Background Long non-coding RNAs (LncRNAs) have emerged as important regulators in many physiological processes in plant. By high-throughput RNA-sequencing, many pathogen-associated lncRNAs were mapped in various plants, and some of them were proved to be involved in plant defense responses. The rice blast disease caused by Magnaporthe oryzae (M. oryzae ) is one of the most destructive diseases in rice. However, M. oryzae-induced lncRNAs in rice is yet to be studied. Findings: We investigated rice lncRNAs that were associated with the rice blast fungus. Totally 83 lncRNAs were up-regulated after blast fungus infection and 78 were down-regulated. Of them, the natural antisense transcripts (NATs) were the most abundant. The expression of some lncRNAs has similar pattern with their host genes or neighboring genes, suggesting a cis function of them in regulating gene transcription level. The deferentially expressed (DE) lncRNAs and genes co-expression analysis revealed some lncRNAs were associated with genes known to be involved in pathogen resistance, and these genes were enriched in terpenoid biosynthesis and defense response by Gene Ontology (GO) enrichment analysis. Interestingly, one of up-regulated DE-intronic RNA was derived from a jasmonate (JA) biosynthetic gene, lipoxygenase RLL (LOX-RLL). Levels of JAs were significantly increased after blast fungus infection. Given that JA is known to regulate blast resistance in rice, we suggested that lncRNA may be involved in JA-mediated rice resistance to blast fungus. Conclusions This study identified blast fungus-responsive lncRNAs in rice, which provides another layer of candidates that regulate rice and blast fungus interactions.

scholarly journals A Mixture of Piper Leaves Extracts and Rhizobacteria for Sustainable Plant Growth Promotion and Bio-Control of Blast Pathogen of Organic Bali Rice

2020 ◽  
Vol 12 (20) ◽  
pp. 8490
Author(s):  
Ni Luh Suriani ◽  
Dewa Ngurah Suprapta ◽  
Novizar Nazir ◽  
Ni Made Susun Parwanayoni ◽  
Anak Agung Ketut Darmadi ◽  
...  
Keyword(s):  
Plant Growth ◽  
Rice Blast ◽  
Growth Yield ◽  
Blast Disease ◽  
Rice Grain ◽  
Potential Yield ◽  
Yield And Quality ◽  
Plant Growth Promoting ◽  
Growth Promoting

Rice is a crop that is consumed as a staple food by the majority of the people in the world and therefore failure in rice crops, due to any reason, poses a severe threat of starvation. Rice blast, caused by a fungus Pyricularia oryzae, has been ranked among the most threatening plant diseases of rice and it is found wherever rice is grown. All of the rice blast disease management strategies employed so far have had limited success and rice blast has never been eliminated from rice fields. Hence, there is a need to look for the best remedy in terms of effectiveness, sustainability, and organic nature of the method. This study was aimed at determining the plant growth-promoting and fungicidal effects of a mixture of Piper caninum and Piper betle var. Nigra leaves extracts and rhizobacteria. Gas chromatography–mass spectrophotometry (GC-MS) analysis of a mixture of leaves extracts of these plants revealed the presence of new bioactive compounds such as alpha.-gurjunene, gamma.-terpinene, and ethyl 5-formyl 3-(2-ethoxycarbonyl) in a mixture of leaves extracts of P. caninum and P. betle var. Nigra. The mixture of these extracts reduced the intensity of blast disease, inhibited P. oryzae, and improved the growth, yield, and quality of Bali rice. All treatments comprising of different concentrations of a mixture of leaves extracts of P. caninum and P. betle var. Nigra plus rhizobacteria exhibited biocontrol and bioefficacy. However, a 2% concentration of a mixture of these leaves extracts with plant growth-promoting rhizobacteria (PGPR) exhibited potent inhibition of growth of P. oryzae, a significant reduction in the intensity of blast disease, and a maximum increase in growth, yield, and quality of Bali rice. In the 15th week, the intensity of blast disease decreased from 80.18% to 7.90%. The mixture of leaves extract + PGPR also improved the height of the plant, the number of tillers, number of leaves, number of grains per panicle, number of heads per panicle, and the full-grain weight per clump. Applications of various concentrations of a mixture of leaves extracts + PGPR resulted in improvement in the potential yield of rice, however, the application of 2% extracts + PGPR gave the highest potential yield of 5.61 tha−1 compared to the low yields in the control and other treatments. The high grain yield observed with the treatment was caused by the low intensity of blast disease. This treatment also strengthened the stem and prevented the drooping of the plant and improved the quality of rice grain.

scholarly journals Evaluation of Biocontrol Activities of Streptomyces spp. against Rice Blast Disease Fungi

Pathogens ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 126 ◽  
Author(s):  
Mathurot Chaiharn ◽  
Teerayut Theantana ◽  
Wasu Pathom-aree
Keyword(s):  
Rice Blast ◽  
Dry Weight ◽  
Rice Cultivar ◽  
Rice Blast Disease ◽  
Blast Disease ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Streptomyces Spp ◽  
Commercially Important

Rhizosphere bacteria can positively influence plant growth by direct and indirect mechanisms. A total of 112 bacterial strains were isolated from the rhizosphere of rice and tested for plant beneficial activities such as siderophore production, cell-wall-degrading enzyme production, hydrogen cyanide (HCN) production and antifungal activity against rice blast disease fungus. The actinomycetes count was 3.8 × 106 CFU/g soil. Streptomyces strains PC 12, D 4.1, D 4.3 and W1 showed strong growth inhibition of blast disease fungus, Pyricularia sp. (87.3%, 82.2%, 80.0% and 80.5%) in vitro. Greenhouse experiments revealed that rice plants treated with Streptomyces strain PC 12 recorded maximum plant height, root length and root dry weight compared to the control. Taxonomic characterization of this strain on the basis of 16S rRNA gene sequence led to its identification as Streptomyces palmae PC 12. Streptomyces palmae PC 12 may be used as biofertilizer to enhance the growth and productivity of commercially important rice cultivar RD6 and the biocontrol of blast disease fungus.

scholarly journals Gene Duplication and Mutation in the Emergence of a Novel Aggressive Allele of the AVR-Pik Effector in the Rice Blast Fungus

2019 ◽  
Vol 32 (6) ◽  
pp. 740-749 ◽  
Author(s):  
Apinya Longya ◽  
Chaivarakun Chaipanya ◽  
Marina Franceschetti ◽  
Josephine H. R. Maidment ◽  
Mark J. Banfield ◽  
...  
Keyword(s):  
Rice Blast ◽  
Blast Disease ◽  
Yield Potential ◽  
Crop Breeding ◽  
Breeding Programs ◽  
Blast Fungus ◽  
Resistant Varieties ◽  
Novel Variant ◽  
Avr Gene

Higher yield potential and greater yield stability are common targets for crop breeding programs, including those in rice. Despite these efforts, biotic and abiotic stresses continue to impact rice production. Rice blast disease, caused by Magnaporthe oryzae, is the most devastating disease affecting rice worldwide. In the field, resistant varieties are unstable and can become susceptible to disease within a few years of release due to the adaptive potential of the blast fungus, specifically in the effector (avirulence [AVR]) gene pool. Here, we analyzed genetic variation of the effector gene AVR-Pik in 58 rice blast isolates from Thailand and examined the interaction between AVR-Pik and the cognate rice resistance gene Pik. Our results reveal that Thai rice blast isolates are very diverse. We observe four AVR-Pik variants in the population, including three previously identified variants, AVR-PikA, AVR-PikD, and AVR-PikE, and one novel variant, which we named AVR-PikF. Interestingly, 28 of the isolates contained two copies of AVR-Pik, always in the combination of AVR-PikD and AVR-PikF. Blast isolates expressing only AVR-PikF show high virulence to rice cultivars encoding allelic Pik resistance genes, and the AVR-PikF protein does not interact with the integrated heavy metal–associated domain of the Pik resistance protein in vitro, suggesting a mechanism for immune evasion.

scholarly journals Study on Antifungal Activity and Ability Against Rice Leaf Blast Disease of Nano Cu-Cu2O/Alginate

2020 ◽  
Author(s):  
Doan Thi Bich Ngoc ◽  
Bui Duy Du ◽  
Le Nghiem Anh Tuan ◽  
Bui Dinh Thach ◽  
Chu Trung Kien ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Untreated Control ◽  
Rice Blast ◽  
Rice Blast Disease ◽  
Blast Disease ◽  
Leaf Blast ◽  
Cu Content ◽  
Polished Rice ◽  
Rice Leaf Blast

Background: Rice blast disease due to Pyricularia oryzae fungus is one of the most destructive ones for rice, causing serious losses in yield and quality in Vietnam and other countries. Studying to develop new fungicides to control the fungal disease effectively is essential.Methods: The sodium alginate-stabilized Cu-Cu2O nanocolloidal solution with a size of about 4 nm and the Cu concentration of 5,000 mg/L was prepared by chemical method. The antifungal activity in vitro against P. oryzae and the ability to control the rice blast disease in the greenhouse of nano Cu-Cu2O/alginate were assessed.Result: The nano Cu-Cu2O/alginate exhibited highly fungal activity with the IC50 of 17.8 mg Cu /L. The disease severity of nano Cu-Cu2O/alginate treatments was in the range of 9.38 - 18.54% in comparison with 47.57% of the untreated control. The grain yield of rice plants treated with nano Cu-Cu2O/alginate increased compared with that of the untreated control, and the Cu content in polished rice was almost the same as that of usually cultured polished rice. Thus, the nano Cu-Cu2O/alginate can be used in agriculture as a plant fungicide, especially for rice cultivation.

scholarly journals Rice Blast Disease (Magnaporthe oryzae): A Menace to Rice Production and Humanity

2020 ◽  
pp. 32-39
Author(s):  
G. O. Agbowuro ◽  
M. S. Afolabi ◽  
E. F. Olamiriki ◽  
S. O. Awoyemi
Keyword(s):  
Food Security ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Disease Incidence ◽  
Rice Production ◽  
Rice Blast Disease ◽  
Control Measures ◽  
Blast Disease ◽  
Economic Losses ◽  
Rice Grain

Rice blast disease is one of the major constraints to rice production, threatening food security globally. Rice grain production losses due to the disease leads economic losses to the farmers, and to an increase in global rice price as a result of the supply that is far below the consumer demand. The losses from the disease annually was estimated to feed over 60 million individual. The disease has been studied comprehensively by researchers due to the importance attached to rice and its vast spread and destructiveness across the globe. A good understanding of the pathogen causing the disease, its life cycle and development, epidemiology, symptoms, management strategy will offer a good insight into the disease incidence and give an appropriate and effective decision-making in its management. Different control measures have been adopted managing the disease, including the use of resistant varieties. Integrated disease management strategies coupled with good agronomy practices are required for successful control of rice blast for food security. This review, therefore, examined the fundamentals of rice blast disease (Magnaporthe oryzae) and offered strategies to minimize the disease activities to ensure proper production and increase the supply of rice grains.

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