Comparison of the Behavior of Epiphytic Fitness Mutants of
            <i>Pseudomonas syringae</i>
            under Controlled and Field Conditions

Beattie, Gwyn A.; Lindow, Steven E.

doi:10.1128/aem.60.10.3799-3808.1994

Cited by 50 publications

(19 citation statements)

References 47 publications

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“…Populations of Pseudomonas spp. applied to aerial surfaces of plants under hot and dry conditions may decrease rapidly (3,4,68). The capacity to survive desiccation and osmotic stress are epiphytic fitness traits of P. syringae (26) and are also likely to influence the capacity of biological control agents like A506 to survive on aerial plant surfaces.…”

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confidence: 99%

Stress Tolerance and Environmental Fitness of Pseudomonas fluorescens A506, Which Has a Mutation in rpoS

Hagen¹,

Stockwell²,

Whistler³

et al. 2009

Phytopathology®

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Establishment of suppressive populations of bacterial biological control agents on aerial plant surfaces is a critical phase in biologically based management of floral diseases. Periodically, biocontrol agents encounter inhospitable conditions for growth on plants; consequently, tolerance of environmental stresses may contribute to their fitness. In many gram-negative bacteria, including strains of Pseudomonas spp., the capacity to survive environmental stresses is influenced by the stationary phase sigma factor RpoS. This study focused on the role of RpoS in stress response and epiphytic fitness of Pseudomonas fluorescens A506, a well-studied bacterial biological control agent. We detected a frameshift mutation in the rpoS of A506 and demonstrated that the mutation resulted in a truncated, nonfunctional RpoS. Using site-directed mutagenesis, we deleted a nucleotide from rpoS, which then encoded a full-length, functional RpoS. We compared the stress response and epiphytic fitness of A506 with derivative strains having the functional full-length RpoS or a disrupted, nonfunctional RpoS. RpoS had little effect on stress response of A506 and no consistent influence on epiphytic population size of A506 on pear or apple leaves or flowers. Although the capacity of strain A506 to withstand exposure to environmental stresses was similar to that of other fluorescent pseudomonads, this capacity was largely independent of rpoS.

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confidence: 99%

Stress Tolerance and Environmental Fitness of Pseudomonas fluorescens A506, Which Has a Mutation in rpoS

Hagen¹,

Stockwell²,

Whistler³

et al. 2009

Phytopathology®

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“…In this sense, lemA might be regarded as a field fitness gene. An extensive search by Lindow et al (2,3,23,24) for genes that affect epiphytic fitness of P. syringae has led to the identification of several genes that affect the fitness of P. syringae on bean plants in the laboratory. These epiphytic fitness mutants were derived from transposon mutagenesis of wild-type strain B728a, the same parent as for the lemA mutant NPS3136.…”

Section: Discussionmentioning

confidence: 99%

“…These epiphytic fitness mutants were derived from transposon mutagenesis of wild-type strain B728a, the same parent as for the lemA mutant NPS3136. Four of the Tn5-induced epiphytic mutants have also been shown to be affected in their abilities to grow and survive on primary leaves of field-grown bean plants (3). However, unlike NPS3136, all four epiphytic fitness mutants were also impaired to different degrees in their abilities to grow when infiltrated into bean leaves in laboratory assays (2).…”

Section: Discussionmentioning

confidence: 99%

Contribution of the Regulatory Gene lemA to Field Fitness of Pseudomonas syringae pv. syringae

Hirano¹,

Ostertag²,

Savage³

et al. 1997

Appl Environ Microbiol

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In Pseudomonas syringae pv. syringae, lemA is required for brown spot lesion formation on snap bean and for production of syringomycin and extracellular proteases (. Plant-Microbe Interact. 3:149-156, 1990). The lemA mutant NPS3136 (lemA1::Tn5) was previously found to be indistinguishable from its pathogenic parent B728a in its ability to grow when infiltrated into bean leaves of plants maintained under controlled environmental conditions (Willis et al., Mol. Plant-Microbe Interact. 3:149-156, 1990). We compared population sizes of NPS3136 and B728aN (a Nal r clone of wild-type B728a) in two field experiments to determine the effect of inactivation of lemA on the fitness of P. syringae pv. syringae. In one experiment, the bacterial strains were spray inoculated onto the foliage of 25-day-old bean plants. In the other, seeds were inoculated at the time of planting. In both experiments, the strains were inoculated individually and coinoculated in a 1:1 ratio. NPS3136 and B728aN achieved similar large population sizes on germinating seeds. However, in association with leaves, population sizes of NPS3136 were diminished relative to those of B728aN in both experiments. Thus, lemA contributed significantly to the fitness of P. syringae pv. syringae in association with bean leaves but not on germinating seeds under field conditions. When NPS3136 was coinoculated with B728aN, the mutant behaved as it did when inoculated alone. However, population sizes of B728aN in the coinoculation treatment were much lower than those when it was inoculated alone. Inactivation of the lemA gene appeared to have rendered the mutant suppressive to B728aN.

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“…Two model strains were used as immigrant bacteria: Pseudomonas syringae B728a ( Ps B728a) and P. fluorescens A506 ( Pf A506). Ps B728a is a foliar pathogen model strain that is the cause of brown spot on bean (24-26). Pf A506 is a model bio-control agent that is used against Erwinia amylovora : the cause of fire blight disease in pear and apple (27, 28).…”

Section: Introductionmentioning

confidence: 99%

Two-way microscale interactions between immigrant bacteria and plant leaf microbiota as revealed by live imaging

Steinberg

Beitelman

Grinberg

et al. 2019

Preprint

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The phyllosphere -the aerial parts of plants -is an important microbial habitat that is home to diverse microbial communities. The spatial organization of bacterial cells on leaf surfaces is non-random and correlates with leaf microscopic features. Yet the role of microscale interactions between cells therein is not well-understood. Here, we ask how interactions between immigrant bacteria and resident microbiota affect the spatial organization of the combined population. By means of live imaging on a simplified in vitro system, we studied the microscale spatial organization of the plant pathogen Pseudomonas syringae B728a and the bio-control agent P. fluorescens A506 when introduced to both native and non-native leaf microbiota (bean and pear). We revealed that both strains preferentially attach to the surface in locations adjacent to microbiota aggregates. Interestingly, preferential attachment of microbiota cells near newly formed P. fluorescens aggregates was also observed. Our results indicate that twoway immigrant bacteria -resident microbiota interactions affect the microscale spatial organization of leaf microbial communities; and that preferential attachmentpreviously suggested as a general strategy that increases fitness under periodic stressis a common surface colonization strategy. The implications of this study are likely relevant to other surface-associated microbial habitats. DiscussionIn summary, through live imaging and spatial analyses at microscale, we show that immigrant bacteria display a non-random spatial colonization pattern with respect to the spatial organization of natural resident leaf microbiota cells. This non-random organization is not necessarily observable by eye, but was revealed by a rigorous image and spatial analysis. As our simplified system excludes the heterogeneity of

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Comparison of the Behavior of Epiphytic Fitness Mutants of Pseudomonas syringae under Controlled and Field Conditions

Cited by 50 publications

References 47 publications

Stress Tolerance and Environmental Fitness of Pseudomonas fluorescens A506, Which Has a Mutation in rpoS

Stress Tolerance and Environmental Fitness of Pseudomonas fluorescens A506, Which Has a Mutation in rpoS

Contribution of the Regulatory Gene lemA to Field Fitness of Pseudomonas syringae pv. syringae

Two-way microscale interactions between immigrant bacteria and plant leaf microbiota as revealed by live imaging

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