Ecotypes and Pathogenicity of Ice-Nucleation-Active<i>Pseudomonas syringae</i>Isolated from Deciduous Fruit Tree Orchards

Gross, Dennis C.; Cody, Y. S.; Proebsting, E. L.; Radamaker, Gary K.; Spotts, R. A.

doi:10.1094/phyto-74-241

Cited by 46 publications

(29 citation statements)

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“…In contrast, strain B301D did not cause disease symptoms in maize and showed insignificant multiplication in leaf tissue. This result for strain B301D is in sharp contrast to its ability to be highly virulent in immature cherry fruits (Scholz-Schroeder et al 2001a) and to cause bacterial canker disease in cherry and apricot orchards (Gross et al 1984).…”

Section: Resultsmentioning

confidence: 86%

“…The B728a ice nucleation gene (Psyr_1608, ~4 kb in size) that is associated with the formation of an outer membrane protein that serves as a nucleus for ice crystal formation is conserved in B301D (PsyrB_07820) (Gross et al. ). In contrast, the ice nucleation gene is truncated in HS191 (PsyrH_18495), whereby it is missing nearly 2 kb of sequence in the center of the open reading frame (ORF) as compared to the gene in B728a and B301D.…”

Section: Resultsmentioning

confidence: 99%

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Comparative genomics ofPseudomonas syringaepv.syringaestrains B301D andHS191 and insights into intrapathovar traits associated with plant pathogenesis

et al. 2015

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Pseudomonas syringae pv. syringae is a common plant-associated bacterium that causes diseases of both monocot and dicot plants worldwide. To help delineate traits critical to adaptation and survival in the plant environment, we generated complete genome sequences of P. syringae pv. syringae strains B301D and HS191, which represent dicot and monocot strains with distinct host specificities. Intrapathovar comparisons of the B301D (6.09 Mb) and HS191 (5.95 Mb plus a 52 kb pCG131 plasmid) genomes to the previously sequenced B728a genome demonstrated that the shared genes encompass about 83% of each genome, and include genes for siderophore biosynthesis, osmotolerance, and extracellular polysaccharide production. Between 7% and 12% of the genes are unique among the genomes, and most of the unique gene regions carry transposons, phage elements, or IS elements associated with horizontal gene transfer. Differences are observed in the type III effector composition for the three strains that likely influences host range. The HS191 genome had the largest number at 25 of effector genes, and seven effector genes are specific to this monocot strain. Toxin production is another major trait associated with virulence of P. syringae pv. syringae, and HS191 is distinguished by genes for production of syringopeptin SP25 and mangotoxin.

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Comparative genomics ofPseudomonas syringaepv.syringaestrains B301D andHS191 and insights into intrapathovar traits associated with plant pathogenesis

et al. 2015

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“…A common predisposing factor to infection of cherry by P. s. syringae is frost injury (Zeller and Schmidle, 1979;Gross et al, 1984). The occurrence of an injurious frost would lead not only to wounding of cherry tissues and leakage of nutrients but also to the sudden release of phenolic glycoside signals, the bulk of which are compart-mentalized in vacuoles (Hosel, 1981).…”

Section: Discussionmentioning

confidence: 99%

Analysis of Sweet cherry (Prunus avium L.) Leaves for Plant Signal Molecules That Activate the syrB Gene Required for Synthesis of the Phytotoxin, Syringomycin, by Pseudomonas syringae pv syringae

Geibel

Bonsall

et al. 1995

Plant Physiol.

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An important aspect of the interaction of Pseudomonas syringae pv syringae with plant hosts is the perception of plant signal molecules that regulate expression of genes, such as syrll, required for synthesis of the phytotoxin, syringomycin. I n this study, the leaves of sweet cherry (Prunus avium 1.) were analyzed to determine the nature of the syrB-inducing activity associated with tissues of a susceptible host. Crude leaf extracts yielded high amounts of total signal activity of more than 12,000 units g-' (fresh weight) based on activation of a syr6-lacZ fusion in strain B3AR132. l h e signal activity was fractionated by C,, reversed-phase high-performance liquid chromatography and found to be composed of phenolic glycosides, which were resolved i n three regions of the high-performance liquid chromatography profile, and sugars, which eluted with the void volume. Two flavonol glycosides, quercetin 3-rutinosyl-4'-glucoside and kaempferol 3-rutinosyl-4'-glucoside, and a flavanone glucoside, dihydrowogonin 7-glucoside, were identified. l h e flavonoid glycosides displayed similar specific signal activities and were comparable in signal activity to arbutin, a phenyl p-glucoside, giving rise to between 120 and 160 units of /3-galactosidase activity at 10 p~. Although o-fructose exhibits intrinsic low leve1 syrll-inducing signal activity, o-fructose enhanced by about 10-fold the signal activities of the flavonoid glycosides at low concentrations (e.g. 10 PM). This demonstrates that flavonoid glycosides, which represent a new class of phenolic plant signals sensed by P. s. syringae, are i n sufficient quantities in the leaves of P. avium to activate phytotoxin synthesis.Bacteria commonly detect in the plant environment specific phenolic compounds that serve as signals in regulating expression of genes critica1 to phytopathogenesis (Peters and Verma, 1990). This was first observed for Agrobacterium tumefaciens, which senses in wounded tissues

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“…2). However, extensive drying for 16 h or longer lowered the MNT to slightly below -3°C, which was nearly 1°C lower than the MNT for stems dried for 4 or 8 h. Stems which had not been previously soaked but nevertheless dried for the same lengths of time also showed a similarly marked lowering of the MNT after 16 At temperatures of 40°C or less the wood-associated ice nuclei were highly stable, exhibiting an MNT of around -2.5°C (Fig. 3).…”

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confidence: 88%

Development, Distribution, and Characteristics of Intrinsic, Nonbacterial Ice Nuclei in Prunus Wood

Gross¹,

Proebsting²,

Maccrindle-Zimmerman³

1988

Plant Physiol.

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Ice nuclei active at approximately -2°C and intrinsic to woody tissues of Prunus spp. were shown to have properties distinct from bacterial ice nuclei. Soaking 5-centimeter peach stem sections in water for 4 hours lowered the mean ice nucleation temperature to below -4°C, nearly 2°C lower than stems inoculated with ice nucleation-active Pseudomonas syringae strain B301D. Ice nucleation activity in peach was fully restored by air-drying woody stem sections for a few hours. The ice nuclei in woody tissue were inactivated between 40 and 50°C, but unaffected by treatment with bacterial ice nucleation inhibitors (i.e. NaOCI, tartaric acid, Triton XQS-20), sulfhydryl reagents (i.e. p-hydroxymercuribenzoate and iodine) and Pronase. Ice nuclei could not be dislodged from stems by sonication and were shown to be equally distributed in peach bud and internodal stem tissue on a per unit mass basis; outer and inner stem tissues were also indistinguishable in ice nucleation activity. Development of ice nuclei in immature peach and sweet cherry stems did not occur until midsummer and their formation was essentially complete by late August. Once formed the ice nuclei intrinsic to woody stems were stable and unaffected by seasonal changes in growth. The apparent physiological function of the ice nuclei is discussed in relation to supercooling and mechanisms of cold hardiness in Prunus spp.Frost tender plants avoid intracellular ice formation and concomitant lethal injury because of the capacity of water in plant cells to supercool. Although pure water supercools to approximately -40°C before homogeneous ice nucleation occurs, ice generally forms at higher temperatures because exogenous ice nuclei order water molecules into a configuration conducive to growth of ice crystals (23, 29). An ice nucleus is active at a discrete threshold temperature, and only a few substances, primarily crystalline forms of organic compounds, show ice nucleation activity at temperatures above -5°C (14). Accordingly, water within the tissues of annual plants, such as beans, tomatoes and maize, has the capacity to supercool to temperatures below -5°C because these tissues lack intrinsic ice nuclei active at high freezing temperatures (23). Appreciable supercooling, however, does not occur in most woody plants such as Prunus spp., which begin freezing around -2°C apparently due to one or more types of constitutive ice nuclei within woody tissue (9, 17). Accordingly, water contained in dormant flower primordia supercools 'This report is based, in part, on research conducted and supported as a part of SAES Western

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Ecotypes and Pathogenicity of Ice-Nucleation-ActivePseudomonas syringaeIsolated from Deciduous Fruit Tree Orchards

Cited by 46 publications

References 0 publications

Comparative genomics ofPseudomonas syringaepv.syringaestrains B301D andHS191 and insights into intrapathovar traits associated with plant pathogenesis

Comparative genomics ofPseudomonas syringaepv.syringaestrains B301D andHS191 and insights into intrapathovar traits associated with plant pathogenesis

Analysis of Sweet cherry (Prunus avium L.) Leaves for Plant Signal Molecules That Activate the syrB Gene Required for Synthesis of the Phytotoxin, Syringomycin, by Pseudomonas syringae pv syringae

Development, Distribution, and Characteristics of Intrinsic, Nonbacterial Ice Nuclei in Prunus Wood

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