Onion Leaf Blight Caused by Xanthomonas campestris: Alternative Hosts and Resistant Onion Genotypes

Tomato (Lycopersicon esculentum), pepper (Capsicum annuum), corn (Zea mays), French bean (Phaseolus vulgaris), soybean (Glycine max), winged bean (Psophocarpus tetragonolobus), lima bean (Phaseolus lunatus), field pea (Pisum sativum), moth bean (Phaseolus aconitifolins), and heliconia (Heliconia bihai) were evaluated as alternative hosts of Xanthomonas campestris, the causal agent of a leaf blight of onion (Allium cepa). On legumes, bacterial growth occurred in planta, and visible disease symptoms developed. From 19 commercial onion genotypes screened for leaf blight resistance, two cultivars, H-942 and H-508, were generally free of symptoms and had restricted bacterial growth in planta. These are the first known reports on alternative hosts of the bacterium and on resistance in onion to leaf blight.

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Xanthan Pyruvilation Is Essential for the Virulence of Xanthomonas campestris pv. campestris

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-06-16-0106-r ◽

2016 ◽

Vol 29 (9) ◽

pp. 688-699 ◽

Cited By ~ 11

Author(s):

María Isabel Bianco ◽

Laila Toum ◽

Pablo Marcelo Yaryura ◽

Natalia Mielnichuk ◽

Gustavo Eduardo Gudesblat ◽

...

Keyword(s):

Xanthomonas Campestris ◽

Defense Responses ◽

Plant Defense Responses ◽

In Planta ◽

Callose Deposition ◽

Disease Symptoms ◽

The Relationship ◽

Plant Surfaces ◽

Xanthomonas Campestris Pv Campestris ◽

Successful Colonization

Xanthan, the main exopolysaccharide (EPS) synthesized by Xanthomonas spp., contributes to bacterial stress tolerance and enhances attachment to plant surfaces by helping in biofilm formation. Therefore, xanthan is essential for successful colonization and growth in planta and has also been proposed to be involved in the promotion of pathogenesis by calcium ion chelation and, hence, in the suppression of the plant defense responses in which this cation acts as a signal. The aim of this work was to study the relationship between xanthan structure and its role as a virulence factor. We analyzed four Xanthomonas campestris pv. campestris mutants that synthesize structural variants of xanthan. We found that the lack of acetyl groups that decorate the internal mannose residues, ketal-pyruvate groups, and external mannose residues affects bacterial adhesion and biofilm architecture. In addition, the mutants that synthesized EPS without pyruvilation or without the external mannose residues did not develop disease symptoms in Arabidopsis thaliana. We also observed that the presence of the external mannose residues and, hence, pyruvilation is required for xanthan to suppress callose deposition as well as to interfere with stomatal defense. In conclusion, pyruvilation of xanthan seems to be essential for Xanthomonas campestris pv. campestris virulence.

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Pseudomonas viridiflava and P. syringae—Natural Pathogens of Arabidopsis thaliana

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2002.15.12.1195 ◽

2002 ◽

Vol 15 (12) ◽

pp. 1195-1203 ◽

Cited By ~ 60

Author(s):

Katrin Jakob ◽

Erica M. Goss ◽

Hitoshi Araki ◽

Tam Van ◽

Martin Kreitman ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Pseudomonas Syringae ◽

Bacterial Growth ◽

Symptom Development ◽

In Planta ◽

Isolation And Identification ◽

Disease Symptoms ◽

Pseudomonas Viridiflava ◽

Bacterial Growth Rates ◽

Plant Pathogen Interactions

We report the isolation and identification of two natural pathogens of Arabidopsis thaliana, Pseudomonas viridiflava and Pseudomonas syringae, in the midwestern United States. P. viridiflava was found in six of seven surveyed Arabidopsis thaliana populations. We confirmed the presence in the isolates of the critical pathogenicity genes hrpS and hrpL. The pathogenicity of these isolates was verified by estimating in planta bacterial growth rates and by testing for disease symptoms and hypersensitive responses to A. thaliana. Infection of 21 A. thaliana ecotypes with six locally collected P. viridiflava isolates and with one P. syringae isolate showed both compatible (disease) and incompatible (resistance) responses. Significant variation in response to infection was evident among Arabidopsis ecotypes, both in terms of symptom development and in planta bacterial growth. The ability to grow and cause disease symptoms on particular ecotypes also varied for some P. viridiflava isolates. We believe that these pathogens will provide a powerful system for exploring coevolution in natural plant-pathogen interactions.

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Effect of Reactive Oxygen Species on Plant Pathogens in planta and on Disease Symptoms

Acta Phytopathologica et Entomologica Hungarica ◽

10.1556/aphyt.39.2004.4.2 ◽

2004 ◽

Vol 39 (4) ◽

pp. 325-345 ◽

Cited By ~ 15

Author(s):

H. M. El-Zahaby ◽

Y. M. Hafez ◽

Z. Király

Keyword(s):

Reactive Oxygen Species ◽

Plant Pathogens ◽

Reactive Oxygen ◽

Oxygen Species ◽

In Planta ◽

Disease Symptoms

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Effect of C6-Volatiles on Bioluminescent Plant Pathogens

HortScience ◽

10.21273/hortsci.33.3.557d ◽

1998 ◽

Vol 33 (3) ◽

pp. 557d-557

Author(s):

Jennifer Warr ◽

Fenny Dane ◽

Bob Ebel

Keyword(s):

Biological Activity ◽

Bacterial Growth ◽

Xanthomonas Campestris ◽

Plant Pathogens ◽

Genetically Engineered ◽

The Other ◽

Computer Assisted ◽

Signal Molecules ◽

Low Concentrations

C6 volatile compounds are known to be produced by the plant upon pathogen attack or other stress-related events. The biological activity of many of these substances is poorly understood, but some might produce signal molecules important in host–pathogen interactions. In this research we explored the possibility that lipid-derived C6 volatiles have a direct effect on bacterial plant pathogens. To this purpose we used a unique tool, a bacterium genetically engineered to bioluminesce. Light-producing genes from a fish-associated bacterium were introduced into Xanthomonas campestris pv. campestris, enabling nondestructive detection of bacteria in vitro and in the plant with special computer-assisted camera equipment. The effects of different C6 volatiles (trans-2 hexanal, trans-2 hexen-1-ol and cis-3 hexenol) on growth of bioluminescent Xanthomonas campestris were investigated. Different volatile concentrations were used. Treatment with trans-2 hexanal appeared bactericidal at low concentrations (1% and 10%), while treatments with the other volatiles were not inhibitive to bacterial growth. The implications of these results with respect to practical use of trans-2 hexanal in pathogen susceptible and resistant plants will be discussed.

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Nucellus and Endosperm in the Seed of Lima Bean (Phaseolus lunatus L.)

Bulletin of the Torrey Botanical Club ◽

10.2307/2482393 ◽

1955 ◽

Vol 82 (1) ◽

pp. 39 ◽

Cited By ~ 6

Author(s):

Clarence Sterling

Keyword(s):

Lima Bean ◽

Phaseolus Lunatus

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The Effect of Fusarium verticillioides Fumonisins on Fatty Acids, Sphingolipids, and Oxylipins in Maize Germlings

International Journal of Molecular Sciences ◽

10.3390/ijms22052435 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2435

Author(s):

Marzia Beccaccioli ◽

Manuel Salustri ◽

Valeria Scala ◽

Matteo Ludovici ◽

Andrea Cacciotti ◽

...

Keyword(s):

Fatty Acids ◽

Fusarium Verticillioides ◽

Fungal Growth ◽

Defense Responses ◽

Ceramide Synthase ◽

Ear Rot ◽

In Planta ◽

Disease Symptoms ◽

The Impact

Fusarium verticillioides causes multiple diseases of Zea mays (maize) including ear and seedling rots, contaminates seeds and seed products worldwide with toxic chemicals called fumonisins. The role of fumonisins in disease is unclear because, although they are not required for ear rot, they are required for seedling diseases. Disease symptoms may be due to the ability of fumonisins to inhibit ceramide synthase activity, the expected cause of lipids (fatty acids, oxylipins, and sphingolipids) alteration in infected plants. In this study, we explored the impact of fumonisins on fatty acid, oxylipin, and sphingolipid levels in planta and how these changes affect F. verticillioides growth in maize. The identity and levels of principal fatty acids, oxylipins, and over 50 sphingolipids were evaluated by chromatography followed by mass spectrometry in maize infected with an F. verticillioides fumonisin-producing wild-type strain and a fumonisin-deficient mutant, after different periods of growth. Plant hormones associated with defense responses, i.e., salicylic and jasmonic acid, were also evaluated. We suggest that fumonisins produced by F. verticillioides alter maize lipid metabolism, which help switch fungal growth from a relatively harmless endophyte to a destructive necrotroph.

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Defects in Mitochondrial and Peroxisomal β-Oxidation Influence Virulence in the Maize Pathogen Ustilago maydis

Eukaryotic Cell ◽

10.1128/ec.00129-12 ◽

2012 ◽

Vol 11 (8) ◽

pp. 1055-1066 ◽

Cited By ~ 27

Author(s):

Matthias Kretschmer ◽

Jana Klose ◽

James W. Kronstad

Keyword(s):

Ustilago Maydis ◽

Short Chain Fatty Acids ◽

Phytopathogenic Fungi ◽

Metabolic Adaptation ◽

In Planta ◽

Gene Encoding ◽

Disease Symptoms ◽

Content Type ◽

C Terminus ◽

Fungal Phytopathogens

ABSTRACTAn understanding of metabolic adaptation during the colonization of plants by phytopathogenic fungi is critical for developing strategies to protect crops. Lipids are abundant in plant tissues, and fungal phytopathogens in the phylum basidiomycota possess both peroxisomal and mitochondrial β-oxidation pathways to utilize this potential carbon source. Previously, we demonstrated a role for the peroxisomal β-oxidation enzyme Mfe2 in the filamentous growth, virulence, and sporulation of the maize pathogenUstilago maydis. However,mfe2mutants still caused disease symptoms, thus prompting a more detailed investigation of β-oxidation. We now demonstrate that a defect in thehad1gene encoding hydroxyacyl coenzyme A dehydrogenase for mitochondrial β-oxidation also influences virulence, although its paralog,had2, makes only a minor contribution. Additionally, we identified a gene encoding a polypeptide with similarity to the C terminus of Mfe2 and designated it Mfe2b; this gene makes a contribution to virulence only in the background of anmfe2Δ mutant. We also show that short-chain fatty acids induce cell death inU. maydisand that a block in β-oxidation leads to toxicity, likely because of the accumulation of toxic intermediates. Overall, this study reveals that β-oxidation has a complex influence on the formation of disease symptoms byU. maydisthat includes potential metabolic contributions to proliferationin plantaand an effect on virulence-related morphogenesis.

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Comparison of bacterial growth and activity of glucanase and chitinase in pepper leaf and flower tissue infected with Xanthomonas campestris pv. vesicatoria

Physiological and Molecular Plant Pathology ◽

10.1016/s0885-5765(05)80075-x ◽

1994 ◽

Vol 45 (3) ◽

pp. 181-188 ◽

Cited By ~ 5

Author(s):

L.W. O'Garro ◽

E. Charlemange

Keyword(s):

Bacterial Growth ◽

Xanthomonas Campestris ◽

Flower Tissue

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Considerations for Verticillium Wilt Resistance Evaluation in Potato

Plant Disease ◽

10.1094/pdis-91-4-0360 ◽

2007 ◽

Vol 91 (4) ◽

pp. 360-367 ◽

Cited By ~ 14

Author(s):

K. E. Frost ◽

D. I. Rouse ◽

S. H. Jansky

Keyword(s):

Disease Severity ◽

Verticillium Wilt ◽

Yield Loss ◽

Control Culture ◽

In Planta ◽

Disease Symptoms ◽

Accuracy And Precision ◽

Population Sizes ◽

Pathogen Colonization ◽

Time Accuracy

Verticillium wilt (Vw), caused by the soilborne fungi Verticillium dahliae and V. albo-atrum, is an important disease of potato (Solanum tuberosum). Host plant resistance is a promising method of Vw control. Culture-based methods that quantify the pathogen in host tissue often are used for Vw resistance screening. To evaluate the processing time, accuracy, and precision of these methods, 46 clones were planted in a field naturally infested with V. dahliae to collect data on visual disease symptoms, pathogen colonization, and yield. In 2002, disease severity explained 4.34% of the variability of yield loss, but the linear relationship between stem colonization and yield loss was not significant. In 2003, stem colonization explained 57.5% of the variability of yield loss, whereas disease severity explained 1.7% of the variability of yield loss. Correlations comparing clone ranks from repeated pathogen measurements indicated that culturing sap from individual stems or bulked stems generated more repeatable clone rankings than culturing dried stems. Clone rankings were more repeatable between years if pathogen measurements were made earlier in the growing season. The results indicate a need to characterize the effect of the environment on the relationship among pathogen population sizes in planta, disease symptoms, and yield loss.

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