Structure of xanthomonadin I, a novel dibrominated aryl-polyene pigment produced by the bacterium

Andrewes, A. G.; Jenkins, Christie L.; Starr, Mortimer P.; Shepherd, J.; Hope, H.

doi:10.1016/s0040-4039(00)92565-6

Cited by 52 publications

(27 citation statements)

References 3 publications

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“…oryzae strains was found to be monobrominated (molecular weight of 551), and a minor dibrominated fraction had a molecular weight of 631 (data not shown). The molecular weights obtained are in a range similar to that reported for the dibrominated form of xanthomonadin (molecular weight, 576) from X. juglandis (2). Therefore, although orf11 is homologous to halogenases, it does not appear to be essential for halogenation of xanthomonadin.…”

Section: Resultssupporting

confidence: 74%

Genetic Locus Encoding Functions Involved in Biosynthesis and Outer Membrane Localization of Xanthomonadin in Xanthomonas oryzae pv. oryzae

et al. 2002

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Xanthomonadins are membrane-bound, brominated, aryl-polyene pigments specific to the genus Xanthomonas. We have characterized a genetic locus (pig) from Xanthomonas oryzae pv. oryzae which contains four open reading frames (ORFs) that are essential for xanthomonadin production. Three of these ORFs are homologous to acyl carrier proteins, dehydratases, and acyl transferases, suggesting a type II polyketide synthase pathway for xanthomonadin biosynthesis. The fourth ORF has no homologue in the database. For the first time, we report that a putative cytoplasmic membrane protein encoded in the pig locus is required for outer membrane localization of xanthomonadin in X. oryzae pv. oryzae. We also report the identification of a novel 145-bp palindromic Xanthomonas repetitive intergenic consensus element that is present in two places in the pig locus. We estimate that more than 100 copies of this element might be present in the genome of X. oryzae pv. oryzae and other xanthomonads.Members of the genus Xanthomonas cause diseases in a wide range of host plants (25). Many of them can also survive and multiply on plant leaf surfaces as epiphytes without affecting the host (15,44). A characteristic feature of most xanthomonads is the production of yellow, membrane-bound (46), halogenated, aryl-polyene pigments (2, 3) called xanthomonadins, which serve as useful chemotaxonomic (45) and diagnostic markers (41). Xanthomonadin is not essential for in planta growth of bacterial cells (13,35,48). However, it is being established progressively that xanthomonadin protects bacteria against photooxidative damage. Pigment-deficient mutants of Xanthomonas juglandis (20), Xanthomonas oryzae pv. oryzae (37), and Xanthomonas campestris pv. campestris (33) are more susceptible to photooxidative damage than are wild-type strains. In vitro, xanthomonadin protects membrane lipids in egg-phosphatidylcholine liposomes against peroxidation (37). A transposon-induced xanthomonadin-deficient mutant of X. campestris pv. campestris has been recently shown to be 1,000-fold reduced for epiphytic survival in conditions of high light intensity (33). These observations suggest that xanthomonadin might aid the survival of xanthomonads on plant leaf surfaces by providing protection against photooxidative damage. In spite of their apparent importance, very little is known about the biosynthesis and mechanism of action of xanthomonadins.An 18.6-kb genomic region from X. campestris pv. campestris that contains seven transcriptional units (pig genes) required for xanthomonadin production has been isolated (34, 35). One of the transcriptional units, pigB, is involved in biosynthesis of a diffusible factor that affects the production of xanthomonadin as well as extracellular polysaccharide (34). The unavailability of nucleotide sequences for these transcriptional units, however, limits further insight into the mechanism of xanthomonadin biosynthesis. X. oryzae pv. oryzae mutants that are defective in shikimate dehydrogenase activity have been shown to be deficie...

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Section: Resultssupporting

confidence: 74%

Genetic Locus Encoding Functions Involved in Biosynthesis and Outer Membrane Localization of Xanthomonadin in Xanthomonas oryzae pv. oryzae

et al. 2002

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“…We also quantified the pigment by assuming that the structure and molar extinction coefficient of xanthomonadin from X. oryzae pv. oryzae are identical to those of a xanthomonadin from X. juglandis (3). Similar conclusions could be drawn by using either method for pigment estimation.…”

supporting

confidence: 74%

“…A characteristic feature of the genus Xanthomonas is the production of yellow, membrane-bound pigments called xanthomonadins (28). The xanthomonadins were initially thought to be carotenoids, but later they were characterized as a unique group of halogenated aryl polyene pigments (2,3). The functional role of xanthomonadins is poorly understood.…”

mentioning

confidence: 99%

Pigment and Virulence Deficiencies Associated with Mutations in the aroE Gene of Xanthomonas oryzae pv. oryzae

Goel

Rajagopal

Sonti

2001

Appl Environ Microbiol

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Xanthomonadins are yellow, membrane-bound pigments produced by members of the genus Xanthomonas. We identified an ethyl methanesulfonate-induced Xanthomonas oryzae pv. oryzae mutant (BXO65) that is deficient for xanthomonadin production and virulence on rice, as well as auxotrophic for aromatic amino acids (Pig ؊ Vir ؊ Aro ؊ ). Reversion analysis indicated that these multiple phenotypes are due to a single mutation. A genomic library of the wild-type strain was used to isolate a 7.0-kb clone that complements BXO65. By transposon mutagenesis, marker exchange, sequence analysis, and subcloning, the complementing activity was localized to a 849-bp open reading frame (ORF). This ORF is homologous to the aroE gene, which encodes shikimate dehydrogenase in various bacterial species. Shikimate dehydrogenase activity was present in the wild-type strain and the mutant with the complementing clone, whereas no activity was found in BXO65. This clone also complemented an Escherichia coli aroE mutant for prototrophy, indicating that aroE is functionally conserved in X. oryzae pv. oryzae and E. coli. The nucleotide sequence of the 2.9-kb region containing aroE revealed that a putative DNA helicase gene is located adjacent to aroE. Our results indicate that aroE is required for normal levels of virulence and xanthomonadin production in X. oryzae pv. oryzae.Xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. Worldwide at least 350 different plant diseases are known to be caused by various xanthomonads (17). A characteristic feature of the genus Xanthomonas is the production of yellow, membrane-bound pigments called xanthomonadins (28). The xanthomonadins were initially thought to be carotenoids, but later they were characterized as a unique group of halogenated aryl polyene pigments (2, 3). The functional role of xanthomonadins is poorly understood. The vast majority of pigment-deficient mutants that have been isolated from several xanthomonads are prototrophs (20, 29) and virulence proficient upon wound inoculation (9,20,29). Pigmentdeficient mutants of Xanthomonas juglandis and X. oryzae pv. oryzae have been reported to be more sensitive to photobiological damage than the wild-type strains are (13, 22), suggesting that the pigment may provide protection against photodamage.An 18.6-kb region containing seven transcriptional units required for xanthomonadin biosynthesis has been isolated from Xanthomonas campestris pv. campestris (20,21). One of the transcriptional units, pigB, encodes a diffusible factor that is involved in both pigment and extracellular polysaccharide production (21). The pigB mutants have also been shown to be impaired for epiphytic survival and host infection (22).We isolated an ethyl methanesulfonate (EMS)-induced pigment-deficient mutant of X. oryzae pv. oryzae that is also virulence deficient and auxotrophic for aromatic amino acids. A genomic clone that restores pigmentation, prototrophy, and virulence to this mutant was isolated by functional complementation. Characte...

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“…Andrewes et al (1,2) determined the chemical structure of the xanthomonadin pigments as mono-or dibromoarylpolyenes. Starr et al (51) showed that xanthomonadins occur exclusively within this genus.…”

Section: Resultsmentioning

confidence: 99%

Numerical Analysis of 295 Phenotypic Features of 266 Xanthomonas Strains and Related Strains and an Improved Taxonomy of the Genus

Mooter¹,

Swings²

1990

International Journal of Systematic Bacteriology

135

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An extensive phenotypic description and an improved classification and nomenclature of the genus Xanthomonas are presented. A total of 266 strains obtained from different geographical areas, including representative strains of all species of the genus Xanthomonas and most pathovars of Xanthomonas campestris, as well as strains which might be genetically related to the genus Xanthomonas, were examined for 295 morphological, biochemical, and physiological features. Similarities among the strains were expressed numerically by using the coefficient of Sokal and Michener. Clustering was performed by using the unweighted average pair group method. The conclusions described below were reached. (i) The genus Xanthomonas comprises at least the following eight phena: X. campestris, Xanthomonas albilineans, Xanthomonas axonopodis, Xanthomonas fragariae, Xanthomonas populi, Xanthomonas maltophilia, Xanthomonas oryzae Swings et al. 1990, and X. campestris pv. graminis Egli and Schmidt 1982 [not X. campestris pv. graminis (Egli et al. 1975) ISPP List 1980]. (ii) X. populi (Ridé 1958) Ridé and Ridé 1978 is a separate species. (iii) X. maltophilia Swings et al. 1983 forms a separate species. (iv) X. campestris pv. oryzae ISPP List 1980 can no longer be regarded as pathovar of X. campestris, and its recent reclassification as a new species, X. oryzae (Swings et al., Int. J. Syst. Bacteriol. 40:309-311, 1990), is supported. (v) X. campestris pv. graminis Egli and Schmidt 1982 [not X. campestris pv. graminis (Egli et al. 1975) ISPP List 1980] seems to form a separate complex of highly related pathovars obtained from members of the Poaceae; the taxonomic implications of this are discussed. (vi) Strains of nearly all X. campestris pathovars cluster together in the X. campestris phenon. Within this species we were able to differentiate some entities on phenotypic grounds; these groups sometimes corresponded to named pathovars (e.g., X. campestris pv. manihotis, X. campestris pv. cassavae, X. campestris pv. phlei). In several other cases, pathovars were found to be heterogeneous. (vii) A number of dubious Pseudomonas species were identified as members of or as being close to Xanthomonas species. Both Pseudomonas betle and Pseudomonas hibiscicola are synonyms of X. maltophilia. We also confirmed that Pseudomonas mangiferaeindicae, Pseudomonas vitiswoodrowii, and Pseudomonas gardneri belong to X. campestris. (viii) Forty phenotypic features allow the differentiation of the eight Xanthomonas phena. (ix) A number of additional features of the genera Xanthomonas and Xylophilus are described.

show abstract

Structure of xanthomonadin I, a novel dibrominated aryl-polyene pigment produced by the bacterium

Cited by 52 publications

References 3 publications

Genetic Locus Encoding Functions Involved in Biosynthesis and Outer Membrane Localization of Xanthomonadin in Xanthomonas oryzae pv. oryzae

Genetic Locus Encoding Functions Involved in Biosynthesis and Outer Membrane Localization of Xanthomonadin in Xanthomonas oryzae pv. oryzae

Pigment and Virulence Deficiencies Associated with Mutations in the aroE Gene of Xanthomonas oryzae pv. oryzae

Numerical Analysis of 295 Phenotypic Features of 266 Xanthomonas Strains and Related Strains and an Improved Taxonomy of the Genus

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