scholarly journals Redox-Active Pyocyanin Secreted by Pseudomonas aeruginosa 7NSK2 Triggers Systemic Resistance to Magnaporthe grisea but Enhances Rhizoctonia solani Susceptibility in Rice

2006 ◽  
Vol 19 (12) ◽  
pp. 1406-1419 ◽  
Author(s):  
David De Vleesschauwer ◽  
Pierre Cornelis ◽  
Monica Höfte
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Rhizoctonia Solani ◽  
Magnaporthe Grisea ◽  
Root Surface ◽  
Sheath Blight ◽  
Blast Disease ◽  
Systemic Resistance ◽  
Sodium Ascorbate ◽  
In Planta ◽  
Pyocyanin Production

Pseudomonas aeruginosa 7NSK2 induces resistance in dicots through a synergistic interaction of the phenazine pyocyanin and the salicylic acid-derivative pyochelin. Root inoculation of the monocot model rice with 7NSK2 partially protected leaves against blast disease (Magnaporthe grisea) but failed to consistently reduce sheath blight (Rhizoctonia solani). Only mutations interfering with pyocyanin production led to a significant decrease in induced systemic resistance (ISR) to M. grisea, and in trans complementation for pyocyanin production restored the ability to elicit ISR. Intriguingly, pyocyanin-deficient mutants, unlike the wild type, triggered ISR against R. solani. Hence, bacterial pyocyanin plays a differential role in 7NSK2-mediated ISR in rice. Application of purified pyocyanin to hydroponically grown rice seedlings increased H2O2 levels locally on the root surface as well as a biphasic H2O2 generation pattern in distal leaves. Co-application of pyocyanin and the antioxidant sodium ascorbate alleviated the opposite effects of pyocyanin on rice blast and sheath blight development, suggesting that the differential effectiveness of pyocyanin with respect to 7NSK2-triggered ISR is mediated by transiently elevated H2O2 levels in planta. The cumulative results suggest that reactive oxygen species act as a double-edged sword in the interaction of rice with the hemibiotroph M. grisea and the necrotroph R. solani.

scholarly journals Uji Efektivitas Rizobakteria Dalam Menghambat Perkembangan Penyakit Hawar Pelepah Daun (Rhizoctonia solani Kuhn.) Pada Padi Secara In Vitro

2020 ◽  
Vol 16 (1) ◽  
pp. 44
Author(s):  
Hanisa Desy Ariani ◽  
Noor Aidawati ◽  
Dewi Arika Adriani
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Rhizoctonia Solani ◽  
Plant Protection ◽  
Block Design ◽  
Sheath Blight ◽  
In Vitro Test ◽  
Sheath Blight Disease ◽  
Randomized Block Design ◽  
Blight Disease

One of the causes of the declining productivity of rice is sheath blight disease caused by the mold Rhizoctonia solani Kuhn. Control of sheath blight disease that is often done by the farmers is by using chemical pesticides (fungicides), which caused environmental problems. One way to reduce the use of pesticides is to biological control by using antagonist bacteria. This study aimed at in vitro test of rhizobacteria in preventing the development of sheath blight disease in rice plants. This research was conducted in the Phytopathology laboratory of Plant Protection Department of Faculty Agriculture, University of Lambung Mangkurat Banjarbaru from March to May 2018. The experiment used a randomized block design with three groups consisting of eight types of rhizobacteria isolates: (r1) Pseudomonas aeruginosa (Barito Kuala), (r2) Bacillus megaterium (Hulu Sungai Tengah), (r3) Azotobacter sp. (Barito Kuala), (r4) Pseudomonas sp. (Hulu Sungai Selatan), (r5) Flavobacterium sp. (Tanah Laut), (r6) Bacillus bodius (Barito Kuala), (r7) Pseudomonas aeruginosa (Hulu Sungai Selatan), (r8) Necercia sp. (Tanah Laut). The results showed that all rhizobacteria have the ability to inhibit the development of R. solani with different percentages of inhibitions. Pseudomonas aeruginosa (Barito Kuala) was the most effective rhizobacteria in inhibiting the development of R. solani.

scholarly journals Induction of systemic resistance (ISR) against sheath blight of rice caused by Rhizoctonia solani Kuhn using biological seed treatment with Trichoderma

2017 ◽  
Vol 9 (3) ◽  
pp. 1861-1865 ◽  
Author(s):  
K. K. Sharma
Keyword(s):  
Rhizoctonia Solani ◽  
Hyphal Growth ◽  
Sheath Blight ◽  
Total Phenol ◽  
Systemic Resistance ◽  
Total Phenol Content ◽  
Phenol Content ◽  
Sheath Blight Disease ◽  
High Yielding Varieties ◽  
Almost All

Sheath blight caused by Rhizoctonia solani Kuhn has recently noticed one of the most important diseases of rice on almost all the high yielding varieties in major rice growing area. In our study morphologically and molecu-larly characterized thirty rhizospheric isolates of Trichoderma (T. harzianum and T. virens) from different locations of Uttarakhand were evaluated for their mycoparasitic ability, disease (sheath blight) suppressing potential and inducing systemic resistance against Rhizoctonia solani. Maximum inhibition in hyphal growth (58.9 %) against R. solani was recorded with isolate PB 2 followed by PB 3 (53.4 %) in confrontation assay. Under glass house con-dition, minimum disease severity (13.6%) was recorded in the treatment where seeds were treated with PB 22 and this treatment also exhibited highest total phenol content (394 μl/g) 168 hours after pathogen inoculation. Total phenol content was also increased maximally (466 μl/g) before pathogen inoculation in the treatment where seeds were treated with PB 22. Moreover, high quality ISR activity was recorded with isolates PB 21, 3, 1, 4, 23, 2 and 16 as they reduced more than 34 percent disease and total phenol contents 456 μl/g, 449 μl/g, 442 μl/g, 440 μl/g and 440 μl/g, 438 μl/g and 431 μl/g were recorded for respective isolates indicated induction of resistance in paddy against sheath blight disease caused by R. solani.

Efficiency of axenically grown Rhizoctonia solani inoculum types in evaluating sheath blight development on rice genotypes

2021 ◽  
Author(s):  
Jagjeet S. Lore ◽  
Jyoti Jain ◽  
Mandeep S. Hunjan ◽  
Ishwinder Kamboj ◽  
Najam W. Zaidi ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Sheath Blight ◽  
Rice Genotypes

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.

Effects of straw incorporation on Rhizoctonia solani inoculum in paddy soil and rice sheath blight severity

2013 ◽  
Vol 152 (5) ◽  
pp. 741-748 ◽  
Author(s):  
H. ZHU ◽  
Z. X. WANG ◽  
X. M. LUO ◽  
J. X. SONG ◽  
B. HUANG
Keyword(s):  
Rhizoctonia Solani ◽  
Disease Severity ◽  
Rice Straw ◽  
Paddy Soil ◽  
Sheath Blight ◽  
Soil Productivity ◽  
Rice Sheath Blight ◽  
Important Method ◽  
Pathogen Dynamics ◽  
Straw Incorporation

SUMMARYIncorporation of rice straw into soil has traditionally been an important method of recycling nutrients and improving soil productivity. Currently, although the effects of straw incorporation on disease severity have been documented, the dynamics of the pathogen in soil after straw incorporation are poorly understood. In the present study, rice straw with various proportions of diseased straw was incorporated at three separate locations (SuPu town, SuSong County and FengYang County) in Anhui province, China. The pathogen dynamics in paddy soil and disease severity of sheath blight during two continuous years from April 2010 to April 2012 were investigated. For all three locations, the amount of pathogen inoculum that persisted in the soil increased with increases in the proportion of diseased straw incorporated. Incorporation of 0·3 and 0·5 diseased straw into soil increased the amount of pathogen inoculum in the soil significantly, whereas incorporation of 0·1 diseased straw into soil had no significant effect on the pathogen inoculum compared with the control (no straw incorporated) or disease severity. Incorporation of healthy rice straw (no disease) resulted in a significant decrease in disease severity, whereas proportions of 0·3 and 0·5 diseased straw resulted in a significant increase of disease severity compared with the control. These results suggested that incorporation of diseased straw enhanced pathogen numbers in soil during the whole decomposition period and increased disease severity. To avoid soil-borne disease accumulation, severely diseased straw should be removed from the field or pre-treated before incorporation.

Functional analysis of polygalacturonase gene RsPG2 from Rhizoctonia solani, the pathogen of rice sheath blight

2017 ◽  
Vol 149 (2) ◽  
pp. 491-502 ◽  
Author(s):  
Xijun Chen ◽  
Li Lili ◽  
Yun Zhang ◽  
Jiahao Zhang ◽  
Shouqiang Ouyang ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Rhizoctonia Solani ◽  
Sheath Blight ◽  
Rice Sheath Blight ◽  
Polygalacturonase Gene

The taxonomical identity of the perfect state of Pyricularia grisea and its allies

1978 ◽  
Vol 56 (2) ◽  
pp. 180-183 ◽  
Author(s):  
H. Yaegashi ◽  
S. Udagawa
Keyword(s):  
Magnaporthe Grisea ◽  
Single Species ◽  
Causal Agent ◽  
Blast Disease ◽  
Stem Rot ◽  
Pyricularia Grisea ◽  
Perfect State ◽  
Conidial State

Magnaporthe grisea is proposed as a comb.nov. for Ceratosphaeria grisea Hébert, the perfect state of Pyricularia grisea (Cke.) Sacc. Pyricularia grisea is very close morphologically to P. oryzae Cav., well known as the causal agent of blast disease on rice. Magnaporthe was recently established in the Diaporthales to accommodate a single species, M. salvinii (Catt.) Krause & Webster, which was described as the cause of stem rot of rice with conidial state known as Nakataea sigmoidea Hara. Based on a review of the taxonomic characters of Ceratosphaeria grisea, the desirability is discussed of its inclusion in the genus Magnaporthe.

scholarly journals The YebC Family Protein PA0964 Negatively Regulates the Pseudomonas aeruginosa Quinolone Signal System and Pyocyanin Production

2008 ◽  
Vol 190 (18) ◽  
pp. 6217-6227 ◽  
Author(s):  
Haihua Liang ◽  
Lingling Li ◽  
Zhaolin Dong ◽  
Michael G. Surette ◽  
Kangmin Duan
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Response Regulator ◽  
Initial Study ◽  
Pfam Family ◽  
Swarming Motility ◽  
Sensing Systems ◽  
Family Protein ◽  
Pyocyanin Production

ABSTRACT Bacterial pathogenicity is often manifested by the expression of various cell-associated and secreted virulence factors, such as exoenzymes, protease, and toxins. In Pseudomonas aeruginosa, the expression of virulence genes is coordinately controlled by the global regulatory quorum-sensing systems, which includes the las and rhl systems as well as the Pseudomonas quinolone signal (PQS) system. Phenazine compounds are among the virulence factors under the control of both the rhl and PQS systems. In this study, regulation of the phzA1B1C1D1E1 (phzA1) operon, which is involved in phenazine synthesis, was investigated. In an initial study of inducing conditions, we observed that phzA1 was induced by subinhibitory concentrations of tetracycline. Screening of 13,000 mutants revealed 32 genes that altered phzA1 expression in the presence of subinhibitory tetracycline concentrations. Among them, the gene PA0964, designated pmpR ( p qsR-mediated P QS r egulator), has been identified as a novel regulator of the PQS system. It belongs to a large group of widespread conserved hypothetical proteins with unknown function, the YebC protein family (Pfam family DUF28). It negatively regulates the quorum-sensing response regulator pqsR of the PQS system by binding at its promoter region. Alongside phzA1 expression and phenazine and pyocyanin production, a set of virulence factors genes controlled by both rhl and the PQS were shown to be modulated by PmpR. Swarming motility and biofilm formation were also significantly affected. The results added another layer of regulation in the rather complex quorum-sensing systems in P. aeruginosa and demonstrated a clear functional clue for the YebC family proteins.

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