scholarly journals Isolation and Characterization of Rhizobacteria from Composts That Suppress the Severity of Bacterial Leaf Spot of Radish

2003 ◽  
Vol 93 (10) ◽  
pp. 1292-1300 ◽  
Author(s):  
M. S. Krause ◽  
T. J. J. De Ceuster ◽  
S. M. Tiquia ◽  
F. C. Michel ◽  
L. V. Madden ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Xanthomonas Campestris ◽  
Systemic Acquired Resistance ◽  
Systemic Disease ◽  
Acquired Resistance ◽  
Systemic Resistance ◽  
Induce Systemic Resistance ◽  
Bacterial Leaf Spot ◽  
Isolation And Characterization ◽  
Compost Amendments

Composts can induce systemic resistance in plants to disease. Unfortunately, the degree of resistance induced seems highly variable and the basis for this effect is not understood. In this work, only 1 of 79 potting mixes prepared with different batches of mature, stabilized composts produced from several different types of solid wastes suppressed the severity of bacterial leaf spot of radish caused by Xanthomonas campestris pv. armoraciae compared with disease on plants produced in a nonamended sphagnum peat mix. An additional batch of compost-amended mix that had been inoculated with Trichoderma hamatum 382 (T382), which is known to induce systemic resistance in plants, also suppressed the disease. A total of 11 out of 538 rhizobacterial strains isolated from roots of radish seedlings grown in these two compostamended mixes that suppressed bacterial leaf spot were able to significantly suppress the severity of this disease when used as inoculum in the compost-amended mixes. The most effective strains were identified as Bacillus sp. based on partial sequencing of 16S rDNA. These strains were significantly less effective in reducing the severity of this disease than T382. A combined inoculum consisting of T382 and the most effective rhizobacterial Bacillus strain was less effective than T382 alone. A drench applied to the potting mix with the systemic acquired resistance-inducing chemical acibenzolar-S-methyl was significantly more effective than T382 in several, but not all tests. We conclude that systemic suppression of foliar diseases induced by compost amendments is a rare phenomenon. Furthermore, inoculation of compost-amended potting mixes with biocontrol agents such as T382 that induce systemic resistance in plants can significantly increase the frequency of systemic disease control obtained with natural compost amendments.

scholarly journals Differential Effectiveness of Salicylate-Dependent and Jasmonate/Ethylene-Dependent Induced Resistance in Arabidopsis

2002 ◽  
Vol 15 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Jurriaan Ton ◽  
Johan A. Van Pelt ◽  
L. C. Van Loon ◽  
Corné M. J. Pieterse
Keyword(s):  
Induced Resistance ◽  
Xanthomonas Campestris ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Defense Responses ◽  
Alternaria Brassicicola ◽  
Systemic Resistance ◽  
Basal Resistance ◽  
Viral Pathogen ◽  
Differential Effectiveness

Salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) are each involved in the regulation of basal resistance against different pathogens. These three signals play important roles in induced resistance as well. SA is a key regulator of pathogen-induced systemic acquired resistance (SAR), whereas JA and ET are required for rhizobacteria-mediated induced systemic resistance (ISR). Both types of induced resistance are effective against a broad spectrum of pathogens. In this study, we compared the spectrum of effectiveness of SAR and ISR using an oomycete, a fungal, a bacterial, and a viral pathogen. In noninduced Arabidopsis plants, these pathogens are primarily resisted through either SA-dependent basal resistance (Peronospora parasitica and Turnip crinkle virus [TCV]), JA/ET-dependent basal resistance responses (Alternaria brassicicola), or a combination of SA-, JA-, and ET-dependent defenses (Xanthomonas campestris pv. armoraciae). Activation of ISR resulted in a significant level of protection against A. brassicicola, whereas SAR was ineffective against this pathogen. Conversely, activation of SAR resulted in a high level of protection against P. parasitica and TCV, whereas ISR conferred only weak and no protection against P. parasitica and TCV, respectively. Induction of SAR and ISR was equally effective against X. campestris pv. armoraciae. These results indicate that SAR is effective against pathogens that in noninduced plants are resisted through SA-dependent defenses, whereas ISR is effective against pathogens that in noninduced plants are resisted through JA/ET-dependent defenses. This suggests that SAR and ISR constitute a reinforcement of extant SA- or JA/ET-dependent basal defense responses, respectively.

scholarly journals Salicylic Acid Biosynthetic Genes Expressed in Pseudomonas fluorescens Strain P3 Improve the Induction of Systemic Resistance in Tobacco Against Tobacco Necrosis Virus

1998 ◽  
Vol 88 (7) ◽  
pp. 678-684 ◽  
Author(s):  
M. Maurhofer ◽  
C. Reimmann ◽  
P. Schmidli-Sacherer ◽  
S. Heeb ◽  
D. Haas ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Systemic Acquired Resistance ◽  
Biocontrol Agent ◽  
Acquired Resistance ◽  
Expression Vectors ◽  
Systemic Resistance ◽  
Tobacco Necrosis Virus ◽  
Induce Systemic Resistance ◽  
Necrosis Virus

Application of salicylic acid induces systemic acquired resistance in tobacco. pchA and pchB, which encode for the biosynthesis of salicylic acid in Pseudomonas aeruginosa, were cloned into two expression vectors, and these constructs were introduced into two root-colonizing strains of P. fluorescens. Introduction of pchBA into strain P3, which does not produce salicylic acid, rendered this strain capable of salicylic acid production in vitro and significantly improved its ability to induce systemic resistance in tobacco against tobacco necrosis virus. Strain CHA0 is a well-described biocontrol agent that naturally produces salicylic acid under conditions of iron limitation. Introduction of pchBA into CHA0 increased the production of salicylic acid in vitro and in the rhizosphere of tobacco, but did not improve the ability of CHA0 to induce systemic resistance in tobacco. In addition, these genes did not improve significantly the capacity of strains P3 and CHA0 to suppress black root rot of tobacco in a gnotobiotic system.

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 Bacterial Leaf Spot of Zinnia Caused by Xanthomonas campestris pv. zinniae, a New Disease in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 1064-1064 ◽  
Author(s):  
I.-S. Myung ◽  
J. Y. Lee ◽  
H. L. Yoo ◽  
J. M. Wu ◽  
H.-S. Shim
Keyword(s):  
Leaf Spot ◽  
Xanthomonas Campestris ◽  
Negative Control ◽  
Gyrb Gene ◽  
23S Rrna ◽  
Distilled Water ◽  
Bacterial Leaf Spot ◽  
Field Isolates ◽  
Sequence Identity ◽  
Physiological Tests

In September 2011, bacterial leaf spot was observed on zinnia plants (Zinnia elegans L.) grown in a garden in Suwon, Korea. Leaf symptoms included angular lesions that were yellow or brown-to-reddish brown in the center. Bacterial isolates (BC3293 to BC3299) were recovered on trypticase soy agar from lesions surface-sterilized in 70% ethyl alcohol for 1 min. Pathogenicity of the isolates was confirmed by spray inoculation with a bacterial suspension (106 CFU/ml) prepared in sterile distilled water and applied to zinnia plants at the four- to five-leaf growth stage (two plants per isolate). Sterile distilled water was used as the negative control. The inoculated plants were incubated in a greenhouse at 26 to 30°C and 95% relative humidity. Characteristic leaf spot symptoms developed on inoculated zinnia plants 5 days after inoculation. No symptoms were observed on the negative control plants. The bacterium reisolated from the inoculated leaves was confirmed through gyrB gene sequence analysis (3). All isolates were gram-negative, aerobic rods, each with a single flagellum. Isolates were positive for catalase and negative for oxidase. The biochemical and physiological tests for differentiation of Xanthomonas were performed using methods described by Shaad et al. (2). The isolates were positive for mucoid growth on yeast extract-dextrose-calcium carbonate agar, growth at 35°C, hydrolysis of starch and esculin, protein digestion, acid production from arabitol, and utilization of glycerol and melibiose. Colonies were negative for ice nucleation, and alkaline in litmus milk. The gyrB gene (870 bp) and the 16S-23S rRNA internal transcribed spacer (ITS) regions (884 bp) were sequenced to aid in identification of the original field isolates using published PCR primer sets Xgyr1BF/Xgyr1BR (3) and A1/B1 (1), respectively. Sequence of the gyrB gene (GenBank Accession Nos. JQ665732 to JQ665738) from the zinnia field isolates shared 100% sequence identity with the reference strain of Xanthomonas campestris pv. zinniae (GenBank Accession No. EU285210), and the ITS sequences (GenBank Accession Nos. JQ665725 to JQ665731) had 99.9% sequence identity with X. campestris pv. zinnia XCZ-1 (GenBank Accession No. EF514223). On the basis of the pathogenicity assays, biochemical and physiological tests, and sequence analyses, the isolates were identified as X. campestris pv. zinniae. To our knowledge, this is the first report of bacterial leaf spot of zinnia caused by X. campestris pv. zinniae in Korea. The disease is expected to result in economic and aesthetic losses to plants in Korean landscapes. Thus, seed treatment with bactericides will be required to control the bacterial leaf spot of zinnia before planting. References: (1) T. Barry et al. The PCR Methods Appl. 1:51, 1991. (2) N. W. Schaad et al. Page 189 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et al., eds. The American Phytopathological Society, St. Paul, MN, 2001. (3) J. M. Young et al. Syst. Appl. Microbiol. 31:366, 2008.

Bacterial leaf spot of hemp caused by Xanthomonas campestris pv. cannabis in Japan

2013 ◽  
Vol 80 (2) ◽  
pp. 164-168 ◽  
Author(s):  
Osamu Netsu ◽  
Toshio Kijima ◽  
Yuichi Takikawa
Keyword(s):  
Leaf Spot ◽  
Xanthomonas Campestris ◽  
Bacterial Leaf Spot

scholarly journals Lack of Induced Systemic Resistance in Peanut to Late Leaf Spot Disease by Plant Growth-Promoting Rhizobacteria and Chemical Elicitors

Plant Disease ◽  
2001 ◽  
Vol 85 (8) ◽  
pp. 879-884 ◽  
Author(s):  
Shouan Zhang ◽  
M. S. Reddy ◽  
Nancy Kokalis-Burelle ◽  
Larry W. Wells ◽  
Stevan P. Nightengale ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Acquired Resistance ◽  
Plant Growth Promoting Rhizobacteria ◽  
Systemic Resistance ◽  
Leaf Spot Disease ◽  
Late Leaf Spot ◽  
Spot Disease ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Significant Disease

A disease assay was optimized for late leaf spot disease of peanut using Cercosporidium per-sonatum in the greenhouse, and this assay was used in attempts to elicit induced systemic resistance using strains of plant growth-promoting rhizobacteria (PGPR) and chemical elicitors. Nineteen strains of spore-forming bacilli PGPR, including strains of Paenibacillus macerans, Brevibacillus brevis, Bacillus laterosporus, B. subtilis, B. pumilus, B. amyloliquefaciens, B. sphaericus, B. cereus, and B. pasteurii, which previously elicited systemic disease control activity on other crops, were evaluated in greenhouse assays. Seven PGPR strains elicited significant disease reduction in a single experiment; however, none repeated significant protection achieved in the greenhouse assay, while significant protection consistently occurred with the fungicide chlorothalonil (Bravo). In other greenhouse trials, neither stem injections of C. personatum nor foliar sprays of chemicals, including salicylic acid, sodium salicylate, isonicotinic acid, or benzo[1,2,3]thiadiazole-7-carbothioc acid S-methyl ester (Actigard), which elicit systemic acquired resistance on other crops, elicited significant disease protection. In contrast, foliar sprays with DL-β-amino-n-butyric acid (BABA), which is an elicitor of localized acquired resistance, resulted in significantly less late leaf spot disease in one of two tests. Combination treatments of four PGPR strains with BABA in the greenhouse did not significantly protect peanut from late leaf spot. Field trials conducted over two growing seasons indicated that none of the 19 PGPR strains, applied as seed treatments at two concentrations, significantly reduced late leaf spot disease. The same chemical elicitors tested in the greenhouse, including BABA, did not elicit significant disease protection. Some combinations of four PGPR and BABA significantly reduced the disease at one but not at two sample times. Collectively, these results suggest that late leaf spot resistance in peanut is not systemically inducible in the same manner as is resistance to diseases in other crops by PGPR and chemical inducers.

scholarly journals Overexpression of a Rice NPR1 Homolog Leads to Constitutive Activation of Defense Response and Hypersensitivity to Light

2005 ◽  
Vol 18 (6) ◽  
pp. 511-520 ◽  
Author(s):  
Mawsheng Chern ◽  
Heather A. Fitzgerald ◽  
Patrick E. Canlas ◽  
Duroy A. Navarre ◽  
Pamela C. Ronald
Keyword(s):  
Systemic Acquired Resistance ◽  
Environmental Changes ◽  
Acquired Resistance ◽  
Northern Analysis ◽  
Wild Type ◽  
Defense Genes ◽  
Isolation And Characterization ◽  
Broad Spectrum Resistance ◽  
Resistance Pathway

Arabidopsis NPR1/NIM1 is a key regulator of systemic acquired resistance (SAR), which confers lasting broad-spectrum resistance. Previous reports indicate that rice has a disease-resistance pathway similar to the Arabidopsis SAR pathway. Here we report the isolation and characterization of a rice NPR1 homologue (NH1). Transgenic rice plants overexpressing NH1 (NH1ox) acquire high levels of resistance to Xanthomonas oryzae pv. oryzae. The resistance phenotype is heritable and correlates with the presence of the transgene and reduced bacterial growth. Northern analysis shows that NH1ox rice spontaneously activates defense genes, contrasting with NPR1-overexpressing Arabidopsis, where defense genes are not activated until induction. Wild-type NH1, but not a point mutant corresponding to npr1-1, interacts strongly with the rice transcription factor rTGA2.2 in yeast two-hybrid. Greenhouse-grown NH1ox plants develop lesion-mimic spots on leaves at preflowering stage although no other developmental effects are observed. However, when grown in growth chambers (GCs) under low light, NH1ox plants are dwarfed, indicating elevated sensitivity to light. The GC-grown NH1ox plants show much higher salicylic acid (SA) levels than the wild type, whereas greenhouse-grown NH1ox plants contain lower SA. These results indicate that NH1 may be involved in the regulation of SA in response to environmental changes.

scholarly journals N-hydroxy-pipecolic acid is a mobile signal that induces systemic disease resistance in Arabidopsis

2018 ◽  
Author(s):  
Yun Chu Chen ◽  
Eric C. Holmes ◽  
Jakub Rajniak ◽  
Jung-Gun Kim ◽  
Sandy Tang ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Systemic Acquired Resistance ◽  
Systemic Disease ◽  
Acquired Resistance ◽  
Bacterial Pathogen ◽  
Pipecolic Acid ◽  
In Planta ◽  
Global Response ◽  
Promising Target ◽  
Pathogenesis Related

AbstractSystemic acquired resistance (SAR) is a global response in plants induced at the site of infection that leads to long-lasting and broad-spectrum disease resistance at distal, uninfected tissues. Despite the importance of this priming mechanism, the identity of the mobile defense signal that moves systemically throughout plants to initiate SAR has remained elusive. In this paper, we describe a new metabolite, N-hydroxy-pipecolic acid (N-OH-Pip), and provide evidence that this molecule is a mobile signal that plays a central role in initiating SAR signal transduction in Arabidopsis thaliana. We demonstrate that FLAVIN-DEPENDENT MONOOXYGENASE 1 (FMO1), a key regulator of SAR-associated defense priming, can synthesize N-OH-Pip from pipecolic acid in planta, and exogenously applied N-OH-PIP moves systemically in Arabidopsis and can rescue the SAR-deficiency of fmo1 mutants. We also demonstrate that N-OH-Pip treatment causes systemic changes in the expression of pathogenesis-related genes and metabolic pathways throughout the plant, and enhances resistance to a bacterial pathogen. This work provides new insight into the chemical nature of a mobile signal for SAR and also suggests that the N-OH-Pip pathway is a promising target for metabolic engineering to enhance disease resistance.

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