scholarly journals Bacillus subtilis and Pseudomonas fluorescens Trigger Common and Distinct Systemic Immune Responses in Arabidopsis thaliana Depending on the Pathogen Lifestyle

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 503
Author(s):  
Ngoc Huu Nguyen ◽  
Patricia Trotel-Aziz ◽  
Sandra Villaume ◽  
Fanja Rabenoelina ◽  
Adrian Schwarzenberg ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Immune Responses ◽  
Signaling Pathways ◽  
Pseudomonas Syringae ◽  
Systemic Resistance ◽  
Functional Study ◽  
Marker Genes ◽  
Beneficial Bacteria ◽  
Bacillus Spp ◽  
Immune Pathways

Plants harbor various beneficial bacteria that modulate their innate immunity, resulting in induced systemic resistance (ISR) against various pathogens. However, the immune mechanisms underlying ISR triggered by Bacillus spp. and Pseudomonas spp. against pathogens with different lifestyles are not yet clearly elucidated. Here, we show that root drenching of Arabidopsis plants with Pseudomonas fluorescensPTA-CT2 and Bacillus subtilis PTA-271 can induce ISR against the necrotrophic fungus B. cinerea and the hemibiotrophic bacterium Pseudomonas syringae Pst DC3000. In the absence of pathogen infection, both beneficial bacteria do not induce any consistent change in systemic immune responses. However, ISR relies on priming faster and robust expression of marker genes for the salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) signaling pathways upon pathogen challenge. These responses are also associated with increased levels of SA, JA, and abscisic acid (ABA) in the leaves of bacterized plants after infection. The functional study also points at priming of the JA/ET and NPR1-dependent defenses as prioritized immune pathways in ISR induced by both beneficial bacteria against B. cinerea. However, B. subtilis-triggered ISR against Pst DC3000 is dependent on SA, JA/ET, and NPR1 pathways, whereas P. fluorescens-induced ISR requires JA/ET and NPR1 signaling pathways. The use of ABA-insensitive mutants also pointed out the crucial role of ABA signaling, but not ABA concentration, along with JA/ET signaling in primed systemic immunity by beneficial bacteria against Pst DC3000, but not against B. cinerea. These results clearly indicate that ISR is linked to priming plants for enhanced common and distinct immune pathways depending on the beneficial strain and the pathogen lifestyle.

scholarly journals Exploring Elicitors of the Beneficial Rhizobacterium Bacillus amyloliquefaciens SQR9 to Induce Plant Systemic Resistance and Their Interactions With Plant Signaling Pathways

2018 ◽  
Vol 31 (5) ◽  
pp. 560-567 ◽  
Author(s):  
Gengwei Wu ◽  
Yunpeng Liu ◽  
Yu Xu ◽  
Guishan Zhang ◽  
Qirong Shen ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Pseudomonas Syringae ◽  
Bacillus Amyloliquefaciens ◽  
Systemic Resistance ◽  
Plant Signaling ◽  
Relative Contribution ◽  
Induced Plant Resistance ◽  
Plant Growth Promoting ◽  
Induction Of Resistance ◽  
Growth Promoting

Beneficial rhizobacteria have been reported to produce various elicitors that induce plant systemic resistance, but there is little knowledge concerning the relative contribution of multiple elicitors from a single beneficial rhizobacterium on the induced systemic resistance in plants and the interactions of these elicitors with plant signaling pathways. In this study, nine mutants of the plant growth–promoting rhizobacterium Bacillus amyloliquefaciens SQR9 deficient in producing the extracellular compounds, including fengycin, bacillomycin D, surfactin, bacillaene, macrolactin, difficidin, bacilysin, 2,3-butandiol, and exopolysaccharides, were tested for the induction of systemic resistance against Pseudomonas syringae pv. tomato DC3000 and Botrytis cinerea and the transcription of the salicylic acid, jasmonic acid, and ethylene signaling pathways in Arabidopsis. Deficiency in producing any of these compounds in SQR9 significantly weakened the induced plant resistance against these phytopathogens. These SQR9-produced elicitors induced different plant defense genes. For instance, the enhancement of 1,3-glucanase (PR2) by SQR9 was impaired by a deficiency of macrolactin but not surfactin. SQR9 mutants deficient in the lipopeptide and polyketide antibiotics remained only 20% functional for the induction of resistance-related gene transcription. Overall, these elicitors of SQR9 could act synergistically to induce plant systemic resistance against different phytopathogens through different signaling pathway genes, and the bacterial antibiotics are major contributors to the induction.

scholarly journals The Plant Growth–Promoting Rhizobacterium Bacillus cereus AR156 Induces Systemic Resistance in Arabidopsis thaliana by Simultaneously Activating Salicylate- and Jasmonate/Ethylene-Dependent Signaling Pathways

2011 ◽  
Vol 24 (5) ◽  
pp. 533-542 ◽  
Author(s):  
Dong-Dong Niu ◽  
Hong-Xia Liu ◽  
Chun-Hao Jiang ◽  
Yun-Peng Wang ◽  
Qing-Ya Wang ◽  
...  
Keyword(s):  
Plant Growth ◽  
Bacillus Cereus ◽  
Signaling Pathways ◽  
Pseudomonas Syringae ◽  
Defense Responses ◽  
Systemic Resistance ◽  
Dependent Manner ◽  
Challenge Inoculation ◽  
Plant Growth Promoting ◽  
Growth Promoting

Bacillus cereus AR156 is a plant growth–promoting rhizobacterium that induces resistance against a broad spectrum of pathogens including Pseudomonas syringae pv. tomato DC3000. This study analyzed AR156-induced systemic resistance (ISR) to DC3000 in Arabidopsis ecotype Col-0 plants. Compared with mock-treated plants, AR156-treated ones showed an increase in biomass and reductions in disease severity and pathogen density in the leaves. The defense-related genes PR1, PR2, PR5, and PDF1.2 were concurrently expressed in the leaves of AR156-treated plants, suggesting simultaneous activation of the salicylic acid (SA)- and the jasmonic acid (JA)- and ethylene (ET)-dependent signaling pathways by AR156. The above gene expression was faster and stronger in plants treated with AR156 and inoculated with DC3000 than that in plants only inoculated with DC3000. Moreover, the cellular defense responses hydrogen peroxide accumulation and callose deposition were induced upon challenge inoculation in the leaves of Col-0 plants primed by AR156. Also, pretreatment with AR156 led to a higher level of induced protection against DC3000 in Col-0 than that in the transgenic NahG, the mutant jar1 or etr1, but the protection was absent in the mutant npr1. Therefore, AR156 triggers ISR in Arabidopsis by simultaneously activating the SA- and JA/ET-signaling pathways in an NPR1-dependent manner that leads to an additive effect on the level of induced protection.

scholarly journals Arabidopsis thaliana Seedlings Influence Bacillus subtilis Spore Formation

2019 ◽  
Vol 32 (9) ◽  
pp. 1188-1195 ◽  
Author(s):  
Vincent Charron-Lamoureux ◽  
Pascale B. Beauregard
Keyword(s):  
Arabidopsis Thaliana ◽  
Bacillus Subtilis ◽  
Systemic Resistance ◽  
Soil System ◽  
Beneficial Effects ◽  
Bacillus Subtilis Spore ◽  
Bacillus Spp ◽  
Plant Growth Promoting ◽  
Growth Promoting

Bacillus subtilis is a Gram-positive plant-growth-promoting rhizobacterium exerting many beneficial effects on plant health. Because they secrete antimicrobial compounds and elicit induced systemic resistance, B. subtilis and phylogenetically related species are of particular interest as antifungals in organic agriculture. These bacteria are also known for their capacity to differentiate phenotypically into endospores able to withstand many environmental stresses. However, although B. subtilis is often inoculated on plants as spores, dynamics of germination and sporulation on roots remain unexplored. Using a hydroponic culture system and a soil system for Arabidopsis thaliana, we observed that B. subtilis spores germinate rapidly on contact with plants. However, the vegetative cells are abundant on roots for only a few days before reversing back to spores. We observed that the germinant receptor GerK and sporulation kinases KinA and KinB identified in vitro control sporulation dynamics on plants. Surprisingly, when plants are inoculated with B. subtilis, free-living cells sporulate more rapidly than plant-associated cells. However, direct contact between plant and bacteria is required for the induction of sporulation in the surrounding B. subtilis. This study has fundamental implications for our understanding of interactions between Bacillus spp. and plants, and particularly for a more efficient usage of B. subtilis as a biofertilizer or biofungicide.

scholarly journals Insights into the Defense-Related Events Occurring in Plant Cells Following Perception of Surfactin-Type Lipopeptide from Bacillus subtilis

2009 ◽  
Vol 22 (4) ◽  
pp. 456-468 ◽  
Author(s):  
E. Jourdan ◽  
G. Henry ◽  
F. Duby ◽  
J. Dommes ◽  
J. P. Barthélemy ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Cyclic Peptide ◽  
Induced Defense ◽  
Plant Cells ◽  
Defense Responses ◽  
Growth Potential ◽  
Systemic Resistance ◽  
Extracellular Medium ◽  
Molecular Events ◽  
Bacillus Spp

Multiple strains of Bacillus subtilis were demonstrated to stimulate plant defense responses, and cyclic lipopeptides may be involved in the elicitation of this induced systemic resistance phenomenon. Here, we further investigated molecular events underlying the interaction between such lipopeptides and plant cells. Addition of surfactin but not fengycin or iturin in the micromolar range to tobacco cell suspensions induced defense-related early events such as extracellular medium alkalinization coupled with ion fluxes and reactive oxygen species production. Surfactin also stimulated the defense enzymes phenylalanine ammonia lyase and lipoxygenase and modified the pattern of phenolics produced by the elicited cells. The occurrence of these surfactin-elicited early events is closely related to Ca2+ influx and dynamic changes in protein phosphorylation but is not associated with any marked phytotoxicity or adverse effect on the integrity and growth potential of the treated tobacco cells. Reduced activity of some homologues also indicates that surfactin perception is dictated by structural clues in both the acyl moiety and cyclic peptide part. Our results suggest that these molecules could interact without irreversible pore formation but in a way sufficient to induce disturbance or transient channeling in the plasma membrane that can, in turn, activate a biochemical cascade of molecular events leading to defensive responses. The present study sheds new light not only on defense-related events induced following recognition of amphiphilic lipopeptides from Bacillus spp. but also more globally on the way elicitors from beneficial bacteria can be perceived by host plant cells.

PHÂN LẬP VÀ TUYỂN CHỌN CÁC CHỦNG BACILLUS ỨC CHẾ VI KHUẨN VIBRIO PARAHAEMOLYTICUS GÂY BỆNH TÔM CHẾT SỚM Ở TỈNH THỪA THIÊN HUẾ

2015 ◽  
Vol 100 (1) ◽  
Author(s):  
Nguyễn Thị Bích Đào ◽  
Trần Quang Khánh Vân ◽  
Nguyễn Văn Khanh ◽  
Nguyễn Quang Linh
Keyword(s):  
Bacillus Subtilis ◽  
Vibrio Parahaemolyticus ◽  
Bacillus Amyloliquefaciens ◽  
Bacillus Spp ◽  
Bacillus Subtilis B1

Khi tình hình bệnh hội chứng tôm chết sớm (EMS) đã gây thiệt hại vô cùng to lớn đối với Nuôi trồng thủy sản thì các giải pháp được đề nghị và áp dụng nhằm hạn chế dịch bệnh. Trong đó, việc tìm hiểu và đưa vi khuẩn có lợi để cạnh tranh và ức chế loài vi khuẩn gây bệnh rất được quan tâm, được cho là giải pháp có nhiều triển vọng phù hợp với điều kiện môi trường, đảm bảo sức khỏe cho con người, cũng như hạn chế được dịch bệnh. Đặc biệt, đưa vi khuẩn Bacillus spp. qua đường tiêu hóa của tôm ngay từ khi mới thả đã hạn chế được mật độ vi khuẩn Vibrio. Nghiên cứu này đã phân lập được các chủng Bacillus subtilis B1, Bacillus subtilis B2, Bacillus amyloliquefaciens B4và thử khả năng đối kháng với vi khuẩn Vibrio parahaemolyticus V1 ở các nồng độ 103, 104, 105, 106 CFU theo dõi ở các thời điểm 6h, 12h, 24h, 48h và 72h. Kết quả cho thấy cả ba chủng vi khuẩn Bacillus trên phân lập được đều có khả năng ức chế tốt vi khuẩn Vibrio parahaemolyticus V1, trong đó vi khuẩn Bacillus amyloliquefaciens B4 làtốt nhất với đường kính vòng kháng khuẩn 52,67 ± 4,31mm ở thời điểm 48h; hai chủng Bacillus subtilis B1, Bacillus subtilis B2 lầnlượt là  49,67 ± 3,15 mm, 44,07 ± 5,19 mm, với mức sai số có ý nghĩa thống kê p < 0,05.

Isolation and Characterization of Broad-Spectrum Disease-Resistant Arabidopsis Mutants

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1661-1671
Author(s):  
Klaus Maleck ◽  
Urs Neuenschwander ◽  
Rebecca M Cade ◽  
Robert A Dietrich ◽  
Jeffery L Dangl ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Constitutive Expression ◽  
Firefly Luciferase ◽  
Marker Genes ◽  
Arabidopsis Mutants ◽  
Isolation And Characterization ◽  
Firefly Luciferase Gene

Abstract To identify Arabidopsis mutants that constitutively express systemic acquired resistance (SAR), we constructed reporter lines expressing the firefly luciferase gene under the control of the SAR-inducible PR-1 promoter (PR-1/luc). After EMS mutagenesis of a well-characterized transgenic line, we screened 250,000 M2 plants for constitutive expression of the reporter gene in vivo. From a mutant collection containing several hundred putative mutants, we concentrated on 16 mutants lacking spontaneous hypersensitive response (HR) cell death. We mapped 4 of these constitutive immunity (cim) mutants to chromosome arms. Constitutive expression of disease resistance was established by analyzing responses to virulent Peronospora parasitica and Pseudomonas syringae strains, by RNA blot analysis for endogenous marker genes, and by determination of salicylic acid levels in the mutants. The variety of the cim phenotypes allowed us to define distinct steps in both the canonical SAR signaling pathway and a separate pathway for resistance to Erysiphe cichoracearum, active in only a subset of the mutants.

scholarly journals An efficient direct screening system for microorganisms that activate plant immune responses based on plant–microbe interactions using cultured plant cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mari Kurokawa ◽  
Masataka Nakano ◽  
Nobutaka Kitahata ◽  
Kazuyuki Kuchitsu ◽  
Toshiki Furuya
Keyword(s):  
Immune Responses ◽  
Plant Defense ◽  
Pseudomonas Syringae ◽  
Large Scale ◽  
Plant Cells ◽  
Defense Responses ◽  
Root Tip ◽  
General Strategy ◽  
Plant Defense Responses ◽  
Microbe Interactions

AbstractMicroorganisms that activate plant immune responses have attracted considerable attention as potential biocontrol agents in agriculture because they could reduce agrochemical use. However, conventional methods to screen for such microorganisms using whole plants and pathogens are generally laborious and time consuming. Here, we describe a general strategy using cultured plant cells to identify microorganisms that activate plant defense responses based on plant–microbe interactions. Microbial cells were incubated with tobacco BY-2 cells, followed by treatment with cryptogein, a proteinaceous elicitor of tobacco immune responses secreted by an oomycete. Cryptogein-induced production of reactive oxygen species (ROS) in BY-2 cells served as a marker to evaluate the potential of microorganisms to activate plant defense responses. Twenty-nine bacterial strains isolated from the interior of Brassica rapa var. perviridis plants were screened, and 8 strains that enhanced cryptogein-induced ROS production in BY-2 cells were selected. Following application of these strains to the root tip of Arabidopsis seedlings, two strains, Delftia sp. BR1R-2 and Arthrobacter sp. BR2S-6, were found to induce whole-plant resistance to bacterial pathogens (Pseudomonas syringae pv. tomato DC3000 and Pectobacterium carotovora subsp. carotovora NBRC 14082). Pathogen-induced expression of plant defense-related genes (PR-1, PR-5, and PDF1.2) was enhanced by the pretreatment with strain BR1R-2. This cell–cell interaction-based platform is readily applicable to large-scale screening for microorganisms that enhance plant defense responses under various environmental conditions.

Enhanced immune responses, PI3K/AKT and JAK/STAT signaling pathways following hepatitis C virus eradication by direct-acting antiviral therapy among Egyptian patients: a case control study

2021 ◽  
Author(s):  
Haidi Karam-Allah Ramadan ◽  
Gamal Badr ◽  
Nancy K Ramadan ◽  
Aml Sayed
Keyword(s):  
Immune Response ◽  
Liver Cirrhosis ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Immune Responses ◽  
Signaling Pathways ◽  
Liver Diseases ◽  
Stat Signaling ◽  
Chronic Hcv ◽  
Direct Acting

Abstract The use of direct-acting antivirals (DAAs) therapy for the treatment of hepatitis C virus (HCV) results in a high sustained virological response (SVR) and subsequently alters liver immunologic environment. However, hepatocellular carcinoma (HCC) may occur after DAAs treatment. We aimed to clarify changes of immune responses, PI3K/AKT and JAK/STAT signaling pathways in HCV-induced liver diseases and HCC following DAAs treatment. Four cohorts are classified as chronic HCV patients, HCV-related cirrhosis without HCC, HCV-related cirrhosis and HCC, and healthy control group. The patient groups were further divided into treated or untreated with DAAs with SVR12. Increased percentages of CD3, CD8 and CD4, decreased CD4/FoxP3/CD25, CD8/PD-1 and CD19/PDL-1 were found in DAAs-treated patients in the three HCV groups. Following DAAs therapy, the levels of ROS, IL-1β, IL-6, IL-8 and TNF-α were significantly decreased in the three HCV groups. Treated HCV patients showed up regulation of p-AKT and p-STAT5 and down regulation of p-STAT3, HIF-1α and COX-2. In conclusion, DAAs enhance the immune response in chronic HCV and liver cirrhosis, hence our study is the first to show change in PI3K/AKT and JAK/STAT signaling pathways in different HCV-induced liver diseases after DAAs. In chronic HCV, DAAs have better impact on the immune response while in liver cirrhosis not all immune changes were prominent.

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.

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