Factors affecting ethylene production by some plant pathogenic bacteria

Swanson, Bert T.; Wilkins, H. F.; Kennedy, B. W.

doi:10.1007/bf02205923

Cited by 22 publications

(6 citation statements)

References 18 publications

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“…Ethylene can either be spontaneously produced at trace amounts via oxidation of 2-keto-4-methylthiobutyric acid or it is generated from α-ketoglutarate and arginine by the ethylene-forming enzyme (EFE) (Eckert et al, 2014). Importantly, the non-enzymatic production of ethylene by Pseudomonas solanacearum is eliminated in the dark (Swanson et al, 1979). Assuming that this is also the case in the PBTS isolates, this would suggest that the observed ethylene production is enzyme-mediated.…”

Section: Pbts1 and Pbts2 Have The Potential To Modulate The Hormone Hmentioning

confidence: 99%

Functional Genomics Insights Into the Pathogenicity, Habitat Fitness, and Mechanisms Modifying Plant Development of Rhodococcus sp. PBTS1 and PBTS2

et al. 2020

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Pistachio Bushy Top Syndrome (PBTS) is a recently emerged disease that has strongly impacted the pistachio industry in California, Arizona, and New Mexico. The disease is caused by two bacteria, designated PBTS1 that is related to Rhodococcus corynebacterioides and PBTS2 that belongs to the species R. fascians. Here, we assessed the pathogenic character of the causative agents and examined their chromosomal sequences to predict the presence of particular functions that might contribute to the observed co-occurrence and their effect on plant hosts. In diverse assays, we confirmed the pathogenicity of the strains on "UCB-1" pistachio rootstock and showed that they can also impact the development of tobacco species, but concurrently inconsistencies in the ability to induce symptoms were revealed. We additionally evidence that fas genes are present only in a subpopulation of pure PBTS1 and PBTS2 cultures after growth on synthetic media, that these genes are easily lost upon cultivation in rich media, and that they are enriched for in an in planta environment. Analysis of the chromosomal sequences indicated that PBTS1 and PBTS2 might have complementary activities that would support niche partitioning. Growth experiments showed that the nutrient utilization pattern of both PBTS bacteria was not identical, thus avoiding co-inhabitant competition. PBTS2 appeared to have the potential to positively affect the habitat fitness of PBTS1 by improving its resistance against increased concentrations of copper and penicillins. Finally, mining the chromosomes of PBTS1 and PBTS2 suggested that the bacteria could produce cytokinins, auxins, and plant growth-stimulating volatiles and that PBTS2 might interfere with ethylene levels, in support of their impact on plant development. Subsequent experimentation supported these in silico predictions. Altogether, our data provide an explanation for the observed pathogenic behavior and unveil part of the strategies used by PBTS1 and PBTS2 to interact with plants.

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Section: Pbts1 and Pbts2 Have The Potential To Modulate The Hormone Hmentioning

confidence: 99%

Functional Genomics Insights Into the Pathogenicity, Habitat Fitness, and Mechanisms Modifying Plant Development of Rhodococcus sp. PBTS1 and PBTS2

et al. 2020

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“…It has also been found that methionine can be converted to the phytotoxin 3-methylthiopropionic acid by Xanthomonas campestris pv. manihotis (13) as well as to the phytohormone ethylene, such as by plant pathogens of the genera Pantoea, Pseudomonas, and Xanthomonas (49). Also, sulfur-containing amino acids, primarily methionine, were found to be required for the in vitro induction of genes involved in pathogenicity and the hypersensitive response (hrp genes) in Xanthomonas campestris pv.…”

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confidence: 99%

Molecular Characterization and Sequence of a Methionine Biosynthetic Locus from Pseudomonas syringae

1998

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Two methionine biosynthetic genes in Pseudomonas syringae pv. syringae, metX andmetW, were isolated, sequenced, and evaluated for their roles in methionine biosynthesis and bacterial fitness on leaf surfaces. The metXW locus was isolated on a 1.8-kb DNA fragment that was required for both methionine prototrophy and wild-type epiphytic fitness. Sequence analysis identified two consecutive open reading frames (ORFs), and in vitro transcription-translation experiments provided strong evidence that the ORFs encode proteins with the predicted molecular masses of 39 and 22.5 kDa. The predicted amino acid sequence of MetX (39 kDa) showed homology to several known and putative homoserineO-acetyltransferases. This enzyme is the first enzyme in the methionine biosynthetic pathway of fungi, gram-negative bacteria of the genus Leptospira, and several gram-positive bacterial genera. Both metX andmetW were required for methionine biosynthesis, and transcription from both genes was not repressed by methionine. MetW (22.5 kDa) did not show significant homology to any known protein, including prokaryotic and eukaryotic methionine biosynthetic enzymes. Several classes of methionine auxotrophs, includingmetX and metW mutants, exhibit reduced fitness on leaf surfaces, indicating a requirement for methionine prototrophy in wild-type epiphytic fitness. This requirement is enhanced under environmentally stressful conditions, suggesting a role for methionine prototrophy in bacterial stress tolerance.

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“…In presence of methionine Agrobacterium rhizogenes, a bacterial species seemingly closely related to strain TNAU 14 (Benckiser et al, 2005), enhances the C 2 H 4 -concentration in the soil air. Agrobacterium rhizogenes shares the conversion of methionine into C 2 H 4 by the 2-keto-4-methylthiobutyric acid pathway with various other bacterial strains (De Bont, 1976) and uses not only methionine as carbon source but also the conversion-product C 2 H 4 (Swanson et al, 1979;Ince and Knowles, 1985;Kepczynska et al, 2003). After C 2 H 4 -consumption the growth of A. rhizogenes and probably that of other C 2 H 4 releasing and degradating bacterial species stops (de Bont, 1976;Arshad and Frankenberger, 1990;Kepczynska et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

Growth, denitrification and nitrate ammonification of the rhizobial strain TNAU 14 in presence and absence of C2H4 and C2H2

Benckiser

2007

Ann. Microbiol.

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initiates as far as a threshold concentration is surpassed manifold physiological reactions on N 2 -fixation. Organic N and ammonium oxidised to NO 3 -means oxygen depletion. Plants suffering under O 2 or infection stress start to excrete ethylene (C 2 H 4 ). C 2 H 4 widens the root intercellulars that O 2 -respiration will continue. Now microbes may more easily enter the plant interior by transforming the reached methionine into C 2 H 4 . Surplus nitrate and C 2 H 4 inhibit nodulation of leguminous plants. Excess NO 3 -in the nodulesphere could be diminished by N 2 -fixing bacteria which in addition can denitrify or ammonify nitrate. Consequently, it was asked whether C 2 H 4 interferes with the potential of N 2 -fixing bacteria to reduce nitrate. The groundnut-nodule isolate TNAU 14, from which it was known that it denitrifies and ammonifies nitrate, served as inoculum of a KNO 3 -mannitol-medium that was incubated under N 2 -, 1% (v/v) N 2 -C 2 H 4 -, and 1% (v/v) N 2 -C 2 H 2 -atmosphere in the laboratory. C 2 H 2 was included into the experiments because it is frequently used to quantify N 2 -fixing potentials (acetylene reduction array, ARA). Gene-16S rDNA-sequencing and physiological tests revealed a high affiliation of strain TNAU 14 to Rhizobium radiobacter and Rhizobium tumefaciens. Strain TNAU 14 released N 2 O into the bottle headspace in all treatments, surprisingly significantly less in presence of C 2 H 2 . Nitrate-ammonification was even completely blocked by C 2 H 2 . C 2 H 4 , in contrast , rather stimulated growth, denitrification, and nitrate-ammonification of strain TNAU 14 which consumed the released NH 4 + during continuing incubation.

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Factors affecting ethylene production by some plant pathogenic bacteria

Cited by 22 publications

References 18 publications

Functional Genomics Insights Into the Pathogenicity, Habitat Fitness, and Mechanisms Modifying Plant Development of Rhodococcus sp. PBTS1 and PBTS2

Functional Genomics Insights Into the Pathogenicity, Habitat Fitness, and Mechanisms Modifying Plant Development of Rhodococcus sp. PBTS1 and PBTS2

Molecular Characterization and Sequence of a Methionine Biosynthetic Locus from Pseudomonas syringae

Growth, denitrification and nitrate ammonification of the rhizobial strain TNAU 14 in presence and absence of C2H4 and C2H2

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