scholarly journals Effects of Jasmonic Acid, Ethylene, and Salicylic Acid Signaling on the Rhizosphere Bacterial Community of Arabidopsis thaliana

2011 ◽  
Vol 24 (4) ◽  
pp. 395-407 ◽  
Author(s):  
Rogier F. Doornbos ◽  
Bart P. J. Geraats ◽  
Eiko E. Kuramae ◽  
L. C. Van Loon ◽  
Peter A. H. M. Bakker
Keyword(s):  
Salicylic Acid ◽  
Bacterial Community ◽  
Induced Resistance ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Systemic Resistance ◽  
Culturable Bacteria ◽  
Wild Type ◽  
Defense Signaling ◽  
Rhizosphere Bacterial Community

Systemically induced resistance is a promising strategy to control plant diseases, as it affects numerous pathogens. However, since induced resistance reduces one or both growth and activity of plant pathogens, the indigenous microflora may also be affected by an enhanced defensive state of the plant. The aim of this study was to elucidate how much the bacterial rhizosphere microflora of Arabidopsis is affected by induced systemic resistance (ISR) or systemic acquired resistance (SAR). Therefore, the bacterial microflora of wild-type plants and plants affected in their defense signaling was compared. Additionally, ISR was induced by application of methyl jasmonate and SAR by treatment with salicylic acid or benzothiadiazole. As a comparative model, we also used wild type and ethylene-insensitive tobacco. Some of the Arabidopsis genotypes affected in defense signaling showed altered numbers of culturable bacteria in their rhizospheres; however, effects were dependent on soil type. Effects of plant genotype on rhizosphere bacterial community structure could not be related to plant defense because chemical activation of ISR or SAR had no significant effects on density and structure of the rhizosphere bacterial community. These findings support the notion that control of plant diseases by elicitation of systemic resistance will not significantly affect the resident soil bacterial microflora.

scholarly journals Induction of Systemic Resistance to Botrytis cinerea in Tomato by Pseudomonas aeruginosa 7NSK2: Role of Salicylic Acid, Pyochelin, and Pyocyanin

2002 ◽  
Vol 15 (11) ◽  
pp. 1147-1156 ◽  
Author(s):  
Kris Audenaert ◽  
Theresa Pattery ◽  
Pierre Cornelis ◽  
Monica Höfte
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Salicylic Acid ◽  
Botrytis Cinerea ◽  
Induced Resistance ◽  
Mammalian Cells ◽  
Cell Damage ◽  
Systemic Resistance ◽  
Wild Type ◽  
Induce Resistance

The rhizobacterium Pseudomonas aeruginosa 7NSK2 produces secondary metabolites such as pyochelin (Pch), its precursor salicylic acid (SA), and the phenazine compound pyocyanin. Both 7NSK2 and mutant KMPCH (Pch-negative, SA-positive) induced resistance to Botrytis cinerea in wild-type but not in transgenic NahG tomato. SA-negative mutants of both strains lost the capacity to induce resistance. On tomato roots, KMPCH produced SA and induced phenylalanine ammonia lyase activity, while this was not the case for 7NSK2. In 7NSK2, SA is probably very efficiently converted to Pch. However, Pch alone appeared not to be sufficient to induce resistance. In mammalian cells, Fe-Pch and pyocyanin can act synergistically to generate highly reactive hydroxyl radicals that cause cell damage. Reactive oxygen species are known to play an important role in plant defense. To study the role of pyocyanin in induced resistance, a pyocyanin-negative mutant of 7NSK2, PHZ1, was generated. PHZ1 is mutated in the phzM gene encoding an O-methyltransferase. PHZ1 was unable to induce resistance to B. cinerea, whereas complementation for pyocyanin production or co-inoculation with mutant 7NSK2-562 (Pch-negative, SA-negative, pyocyanin-positive) restored induced resistance. These results suggest that pyocyanin and Pch, rather than SA, are the determinants for induced resistance in wild-type P. aeruginosa 7NSK2.

scholarly journals dl-β-Aminobutyric Acid–Induced Resistance of Potato Against Phytophthora infestans Requires Salicylic Acid but Not Oxylipins

2010 ◽  
Vol 23 (5) ◽  
pp. 585-592 ◽  
Author(s):  
Lennart Eschen-Lippold ◽  
Simone Altmann ◽  
Sabine Rosahl
Keyword(s):  
Salicylic Acid ◽  
Phytophthora Infestans ◽  
Induced Resistance ◽  
Crop Plants ◽  
Aminobutyric Acid ◽  
Systemic Resistance ◽  
Lipoxygenase Pathway ◽  
Promising Alternative ◽  
Functional Analyses ◽  
Late Blight Pathogen

Inducing systemic resistance responses in crop plants is a promising alternative way of disease management. To understand the underlying signaling events leading to induced resistance, functional analyses of plants defective in defined signaling pathway steps are required. We used potato, one of the economically most-important crop plants worldwide, to examine systemic resistance against the devastating late blight pathogen Phytophthora infestans, induced by treatment with dl-β-aminobutyric acid (BABA). Transgenic plants impaired in either the 9-lipoxygenase pathway, which produces defense-related compounds, or the 13-lipoxygenase pathway, which generates jasmonic acid–derived signals, expressed wild-type levels of BABA-induced resistance. Plants incapable of accumulating salicylic acid (SA), on the other hand, failed to mount this type of induced resistance. Consistently, treatment of these plants with the SA analog 2,6-dichloroisonicotinic acid restored BABA-induced resistance. Together, these results demonstrate the indispensability of a functional SA pathway for systemic resistance in potato induced by BABA.

scholarly journals Induced Systemic Resistance in Arabidopsis thaliana Against Pseudomonas syringae pv. tomato by 2,4-Diacetylphloroglucinol-Producing Pseudomonas fluorescens

2012 ◽  
Vol 102 (4) ◽  
pp. 403-412 ◽  
Author(s):  
David M. Weller ◽  
Dmitri V. Mavrodi ◽  
Johan A. van Pelt ◽  
Corné M. J. Pieterse ◽  
Leendert C. van Loon ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pseudomonas Fluorescens ◽  
Induced Resistance ◽  
Pseudomonas Syringae ◽  
Induced Systemic Resistance ◽  
Signal Transduction Pathway ◽  
Systemic Resistance ◽  
Wild Type ◽  
Challenge Inoculation ◽  
Dependent Signal

Pseudomonas fluorescens strains that produce the polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are among the most effective rhizobacteria that suppress root and crown rots, wilts, and damping-off diseases of a variety of crops, and they play a key role in the natural suppressiveness of some soils to certain soilborne pathogens. Root colonization by 2,4-DAPG-producing P. fluorescens strains Pf-5 (genotype A), Q2-87 (genotype B), Q8r1-96 (genotype D), and HT5-1 (genotype N) produced induced systemic resistance (ISR) in Arabidopsis thaliana accession Col-0 against bacterial speck caused by P. syringae pv. tomato. The ISR-eliciting activity of the four bacterial genotypes was similar, and all genotypes were equivalent in activity to the well-characterized strain P. fluorescens WCS417r. The 2,4-DAPG biosynthetic locus consists of the genes phlHGF and phlACBDE. phlD or phlBC mutants of Q2-87 (2,4-DAPG minus) were significantly reduced in ISR activity, and genetic complementation of the mutants restored ISR activity back to wild-type levels. A phlF regulatory mutant (overproducer of 2,4-DAPG) had ISR activity equivalent to the wild-type Q2-87. Introduction of DAPG into soil at concentrations of 10 to 250 μM 4 days before challenge inoculation induced resistance equivalent to or better than the bacteria. Strain Q2-87 induced resistance on transgenic NahG plants but not on npr1-1, jar1, and etr1 Arabidopsis mutants. These results indicate that the antibiotic 2,4-DAPG is a major determinant of ISR in 2,4-DAPG-producing P. fluorescens, that the genotype of the strain does not affect its ISR activity, and that the activity induced by these bacteria operates through the ethylene- and jasmonic acid-dependent signal transduction pathway.

scholarly journals The Involvement of Jasmonic Acid, Ethylene, and Salicylic Acid in the Signaling Pathway of Clonostachys rosea-Induced Resistance to Gray Mold Disease in Tomato

2019 ◽  
Vol 109 (7) ◽  
pp. 1102-1114 ◽  
Author(s):  
Qiuying Wang ◽  
Xiuling Chen ◽  
Xinfeng Chai ◽  
Dongqi Xue ◽  
Wei Zheng ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Induced Resistance ◽  
Plant Pathogens ◽  
Gray Mold ◽  
Mitogen Activated Protein Kinase ◽  
Signal Molecules ◽  
Clonostachys Rosea ◽  
Tomato Production ◽  
Regulatory Pathways

Tomato gray mold disease caused by Botrytis cinerea is a serious disease that threatens tomato production around the world. Clonostachys rosea has been used successfully as a biocontrol agent against divergent plant pathogens, including B. cinerea. To understand the signal transduction pathway of C. rosea-induced resistance to tomato gray mold disease, the effects of C. rosea on gray mold tomato leaves along with changes in the activities of three defense enzymes (phenylalanine ammonialyase [PAL], polyphenol oxidase [PPO], and catalase [CAT]), second messengers (nitric oxide [NO], hydrogen peroxide [H2O2], and superoxide anion radical [O2−]), and stress-related genes (mitogen-activated protein kinase [MAPK], WRKY, Lexyl2, and atpA) in four different hormone-deficient (jasmonic acid [JA], ethylene [ET], salicylic acid [SA], and gibberellin) tomato mutants were investigated. The results revealed that C. rosea significantly inhibited the growth of mycelia and spore germination of B. cinerea. Furthermore, it reduced the incidence of gray mold disease, induced higher levels of PAL and PPO, and induced lower levels of CAT activities in tomato leaves. Moreover, it also increased NO, H2O2, and O2− levels and the gene expression levels of WRKY, MAPK, atpA, and Lexyl2. The incidence of gray mold disease in four hormone-deficient mutants was higher than that in the corresponding wild-type tomato plants. Among all of these hormone-deficient tomato mutants, JA had the most significant effect in regulating the different signal molecules. Additional study suggested that JA upregulated the expression of Lexyl2, MAPK, and WRKY but downregulated atpA. Furthermore, JA also enhanced the activity of PAL, PPO, and CAT and the production of NO and H2O2. SA downregulated CAT and PAL, whereas ET upregulated PAL but downregulated CAT. This study is of significance in understanding the regulatory pathways and biocontrol mechanism of C. rosea against B. cinerea.

scholarly journals Bacillus velezensis PEA1 Inhibits Fusarium oxysporum Growth and Induces Systemic Resistance to Cucumber Mosaic Virus

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1312 ◽  
Author(s):  
Ahmed Abdelkhalek ◽  
Said I. Behiry ◽  
Abdulaziz A. Al-Askar
Keyword(s):  
Antiviral Activity ◽  
Fusarium Oxysporum ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Mass Spectrometry Analysis ◽  
Systemic Resistance ◽  
Bacillus Velezensis ◽  
Antiviral Activities

Bacillus velezensis manifests robust biocontrol activity against fungal plant pathogens; however, its antiviral activity has rarely been investigated. Bacillus velezensis strain PEA1 was isolated, characterized, and evaluated for antifungal and antiviral activities against Fusarium oxysporum MT270445 and cucumber mosaic virus (CMV) MN594112. Our findings proved that strain PEA1 had intense antagonist activity against F.oxysporum. Under greenhouse conditions, the antiviral activities (protective, curative, and inactivation) of PEA1-culture filtrate (CF) on Datura stramonium plants were assayed, using a half-leaf method. The inactivation treatment exhibited the highest inhibition rate (97.56%) and the most considerable reduction of CMV-CP accumulation levels (2.1-fold) in PEA1-CF-treated plants when compared with untreated plants (26.9-fold). Furthermore, PEA1-CF induced systemic resistance with significantly elevated transcriptional levels of PAL, CHS, HQT, PR-1, and POD genes in D. stramonium leaves after all treatments. Gas chromatography‒mass spectrometry analysis showed that pyrrolo[1,2-a]pyrazine-1,4-dione is the main compound in the PEA1-CF ethyl acetate extract, which may act as an elicitor molecule that induces plant systemic resistance and inhibits both fungal growth and viral replication. Consequently, B. velezensis can be considered as a potential source for the production of bioactive compounds for the management of plant diseases. To our knowledge, this is the first report of the antiviral activity of B. velezensis against plant viral infection.

scholarly journals Biological Control of Plant Diseases with Composts

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 698b-698
Author(s):  
Harry A.J. Hoitink ◽  
Alex G. Stone ◽  
David Y. Han ◽  
Weidzheng Zhang ◽  
Warren A. Dick
Keyword(s):  
Plant Pathogens ◽  
Plant Diseases ◽  
Plant Roots ◽  
Systemic Resistance ◽  
Decomposition Level ◽  
Loading Rates ◽  
Plant Parts ◽  
Root Rots ◽  
Compost Plant ◽  
Degree Of Control

Compost offers the potential to suppress root rots and vascular wilts caused by soilborne plant pathogens, as well as plant diseases affecting aerial plant parts. Many factors affect the degree of control obtained. They include the decomposition level (stability) of the compost, the types of microorganisms colonizing the organic matter after peak heating of the compost, plant nutrients released by the compost (fertility), its salinity, loading rates, and other factors. Biocontrol agents in composts induce suppression through various mechanisms, including competition, antibiosis, hyperparasitism, and the induction of systemic resistance in the plant (roots as well as foliage) to pathogens. Examples of each of the effects are reviewed.

scholarly journals Effect of the Nanoparticle Exposures on the Tomato Bacterial Wilt Disease Control by Modulating the Rhizosphere Bacterial Community

2021 ◽  
Vol 23 (1) ◽  
pp. 414
Author(s):  
Hubiao Jiang ◽  
Luqiong Lv ◽  
Temoor Ahmed ◽  
Shaomin Jin ◽  
Muhammad Shahid ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Metal Oxide ◽  
Relative Abundance ◽  
Bacterial Wilt ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Early Stage ◽  
Shannon Index ◽  
Rhizosphere Bacterial Community ◽  
Tomato Bacterial Wilt

Ralstonia Solanacearum is one of the most infectious soil-borne bacterial plant pathogens, causing tomato bacterial wilt (TBW). Nanotechnology is an emerging area of research, particularly the application of nanoparticles (NPs) as nanopesticides to manage plant disease is gaining attention nowadays. However, the interaction between NPs and rhizosphere bacterial communities remains largely elusive. This study indicated that metal NPs (CuO, ZnO, and FeO) reduced the incidence of bacterial wilt to varying degrees and affected the composition and structure of the rhizosphere bacterial community. The results revealed that the application of metal oxide NPs can improve the morphological and physiological parameters of TBW infected tomato plants. Among all, CuONPs amendments significantly increase the Chao1 and Shannon index. In the early stage (the second week), it significantly reduces the relative abundance of pathogens. However, the relative abundance of beneficial Streptomyces bacteria increased significantly, negatively correlated with the relative abundance of pathogenic bacteria. In addition, the nano-treatment group will enrich some potential beneficial bacteria such as species from Sphingomonadaceae, Rhizobiaceae, etc. In general, our research provides evidence and strategies for preventing and controlling soil-borne disease tomato bacterial wilt with metal oxide NPs.

scholarly journals Control of A Tomato Plant Root-Knot Nematode By Induced Resistance Of Oxalic Acid Derived From Aspergillus Niger

2021 ◽  
Author(s):  
Jehyeong Yeon ◽  
Ae Ran Park ◽  
MinKyu-Kang ◽  
Van Thi Nguyen ◽  
Yookyung Lee ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Oxalic Acid ◽  
Induced Resistance ◽  
Tomato Plant ◽  
Field Experiments ◽  
Plant Root ◽  
Foliar Spray ◽  
Plant Diseases ◽  
Systemic Resistance ◽  
Soil Drench

Abstract Aspergillus niger F22 producing oxalic acid (OA) as a nematicidal component is currently used as a microbial nematicide. OA is known to induce systemic resistance in plant diseases caused by fungi, bacteria, and viruses, but the induced resistance of OA has not yet been elucidated in plant diseases caused by root-knot nematodes (RKNs). In this study, we investigated the functional mechanism of induced resistance of A. niger F22 formulation (Nemafree, 20% SC) and OA in tomato plant RKN disease caused by Meloidogyne incognita and analyzed their effectiveness against the disease. Foliar spray and soil drench treatments of Nemafree and OA were effective in the management of M. incognita in tomato plant in-pot experiments. When Nemafree and OA were applied 4 days before inoculation of M. incognita eggs, the treatments of Nemafree (4,000-fold dilution) and OA (0.22 mM) reduced root gall formation by more than 50%. The soil drench treatment also effectively suppressed RKN disease in field experiments. Moreover, the treatments of Nemafree and OA enhanced the transcriptional expression of pathogenesis-related 1 gene, plant proteinase inhibitor-II, and polyphenol oxidase genes and improved the production of total phenols, flavonoids, and lignin in the tomato plants infected with M. incognita. These results demonstrate that RKN diseases can be effectively controlled by induced resistance even at low concentrations of Nemafree or OA. Accordingly, our study provides evidence for more economical and efficient application strategies of microbial nematicides that control RKNs under field conditions.

scholarly journals Nanogram Amounts of Salicylic Acid Produced by the Rhizobacterium Pseudomonas aeruginosa 7NSK2 Activate the Systemic Acquired Resistance Pathway in Bean

1999 ◽  
Vol 12 (5) ◽  
pp. 450-458 ◽  
Author(s):  
Geert De Meyer ◽  
Kristof Capieau ◽  
Kris Audenaert ◽  
Antony Buchala ◽  
Jean-Pierre Métraux ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Salicylic Acid ◽  
Induced Resistance ◽  
Phenylalanine Ammonia Lyase ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Systemic Resistance ◽  
Resistance Pathway ◽  
Lyase Activity ◽  
Phenylalanine Ammonia Lyase Activity

Root colonization by specific nonpathogenic bacteria can induce a systemic resistance in plants to pathogen infections. In bean, this kind of systemic resistance can be induced by the rhizobacterium Pseudomonas aeruginosa 7NSK2 and depends on the production of salicylic acid by this strain. In a model with plants grown in perlite we demonstrated that Pseudomonas aeruginosa 7NSK2-induced resistance is equivalent to the inclusion of 1 nM salicylic acid in the nutrient solution and used the latter treatment to analyze the molecular basis of this phenomenon. Hydroponic feeding of 1 nM salicylic acid solutions induced phenylalanine ammonia-lyase activity in roots and increased free salicylic acid levels in leaves. Because pathogen-induced systemic acquired resistance involves similar changes it was concluded that 7NSK2-induced resistance is mediated by the systemic acquired resistance pathway. This conclusion was validated by analysis of phenylalanine ammonia-lyase activity in roots and of salicylic acid levels in leaves of soil-grown plants treated with Pseudomonas aeruginosa. The induction of systemic acquired resistance by nanogram amounts of salicylic acid is discussed with respect to long-distance signaling in systemic acquired resistance.

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