Characterization of the Erwinia chrysanthemi gan locus involved in galactan catabolism. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Bacteriology Année : 2007

Characterization of the Erwinia chrysanthemi gan locus involved in galactan catabolism.

Résumé

beta-1,4-galactan is a major component of the ramified regions of pectin. Analysis of the genome of the plant pathogenic bacteria Erwinia chrysanthemi revealed the presence of a cluster of eight genes encoding proteins potentially involved in galactan utilization. The predicted transport system would comprise a specific porin GanL and an ABC transporter made of four proteins GanFGK2. Degradation of galactans would be catalyzed by the periplasmic 1,4-beta-endogalactanase GanA which released oligogalactans from trimer to hexamer. After their transport through the inner membrane, oligogalactans would be degraded into galactose by the cytoplasmic 1,4-beta-exogalactanase GanB. Mutants affected for the porin or endogalactanase were unable to grow on galactans but they grew on galactose and on a mixture of galactotriose, galactotetraose, galactopentaose and galactohexaose. Mutants affected for the periplasmic galactan binding protein, the transporter ATPase or the exogalactanase were only able to grow on galactose. Thus, the phenotypes of these mutants confirmed the functionality of the gan locus in transport and catabolism of galactans. These mutations did not affect the virulence of E. chrysanthemi on chicory leaves, potato tubers or Saintpaulia ionantha, suggesting an accessory role of galactan utilization in the bacterial pathogeny.

Dates et versions

hal-00169016 , version 1 (31-08-2007)

Identifiants

Citer

Aurélie Delangle, Anne-France Prouvost, Virginie Cogez, Jean-Pierre Bohin, Jean-Marie Lacroix, et al.. Characterization of the Erwinia chrysanthemi gan locus involved in galactan catabolism.. Journal of Bacteriology, 2007, 189 (19), pp.7053-7061. ⟨10.1128/JB.00845-07⟩. ⟨hal-00169016⟩
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