Genetic and Biochemical Characterization of the Pathway in Pantoea citrea Leading to Pink Disease of Pineapple

Abstract

Pink disease of pineapple, caused by Pantoea citrea, is characterized by a dark coloration on fruit slices after autoclaving. This coloration is initiated by the oxidation of glucose to gluconate, which is followed by further oxidation of gluconate to as yet unknown chromogenic compounds. To elucidate the biochemical pathway leading to pink disease, we generated six coloration-defective mutants of P. citrea that were still able to oxidize glucose into gluconate. Three mutants were found to be affected in genes involved in the biogenesis of c-type cytochromes, which are known for their role as specific electron acceptors linked to dehydrogenase activities. Three additional mutants were affected in different genes within an operon that probably encodes a 2-ketogluconate dehydrogenase protein. These six mutants were found to be unable to oxidize gluconate or 2-ketogluconate, resulting in an inability to produce the compound 2,5-diketogluconate (2,5-DKG). Thus, the production of 2,5-DKG by P. citrea appears to be responsible for the dark color characteristic of the pink disease of pineapple.

Molecular Properties of Membrane-Bound FAD-ContainingD-Sorbitol Dehydrogenase from ThermotolerantGluconobacter frateuriiIsolated from Thailand

“…From bacteria other than acetic acid bacteria, membrane-bound GADH and 2KGDH from E. cypripedii 32) and P. agglomerans or P. citrea 33) respectively have been reported to contain similar cytochrome c subunits. These cytochrome c subunits show high identity to each other in amino acid sequence (Fig.…”

A Conserved Histidine in Cytochrome c Maturation Permease CcmB of Shewanella putrefaciens Is Required for Anaerobic Growth below a Threshold Standard Redox Potential

“…Pseudomonas fluorescens CcmC mutants are unable to complete synthesis of the siderophore pyoverdine (2). CcmC mutants of Pantoea citrea, Gluconacetobacter diazotrophicus, and Pseudomonas putida are unable to oxidize gluconate and 2-ketogluconate, synthesize indole-3-acetic acid, or isomerize (cis-trans) unsaturated fatty acids, respectively (28,36,51). The seemingly unrelated Ccm mutant phenotypes are postulated to reflect improper redox homeostasis in the periplasm (2,8).…”

A FAFLP system for the improved identification of plant-pathogenic and plant-associated species of the genus Pantoea

“…Pantoea agglomerans is best known for causing crown and root gall of Gypsophila paniculata [6] and Pantoea ananatis causes a range of diseases on a wide variety of agricultural crops, the most recent including rice [8], Eucalyptus [9], maize [14] and sudangrass [3]. Pantoea citrea is associated with citrus fruit and causes pink disease of pineapple [11] and [15]. Although Pantoea dispersa, Pantoea punctata and Pantoea terrea have been isolated from the environment, they have not been found to be associated with diseases of plants.…”