Microbial Ecology

, Volume 62, Issue 2, pp 446–459

Purple-Pigmented Violacein-Producing Duganella spp. Inhabit the Rhizosphere of Wild and Cultivated Olives in Southern Spain

  • Sergio Aranda
  • Miguel Montes-Borrego
  • Blanca B. Landa
Plant Microbe Interactions

DOI: 10.1007/s00248-011-9840-9

Cite this article as:
Aranda, S., Montes-Borrego, M. & Landa, B.B. Microb Ecol (2011) 62: 446. doi:10.1007/s00248-011-9840-9

Abstract

Bacteria have evolved mechanisms that allow them to grow and survive in highly competitive environments like soil and the rhizosphere. Using classical microbiological, physiological, and genetic analyses, we isolated and identified for the first time Duganella spp. associated with the rhizosphere of woody plants in Mediterranean environments that are able to produce violacein, a blue–purple secondary metabolite of considerable biotechnological interest. Based on physiological and biochemical characterization and phylogenetic analysis of different genes including 16S rRNA, gyrB, and vioA (implicated in the synthesis of violacein), the seven Duganella spp. strains isolated and studied were differentiated according to their host of origin (wild versus cultivated olives) and potentially might belong to new species. All the Duganella spp. strains produced violacein in vitro, with natural production levels significantly higher than that previously reported for other violacein-producing bacteria without optimizing growing conditions. The important biological, medical, and industrial applications of violacein make these bacteria good candidates for their biotechnological exploitation because low violacein yields are considered as one of the main limitations of using wild-type strains for extensive exploitation and pigment production. Independent of violacein production, purple-pigmented strains from olives showed proteolytic and lipolytic activities and a weak siderophore production. No in vitro inhibitory activity was demonstrated for bacteria or crude violacein filtrates against plant-pathogenic Gram-negative bacteria and fungi, but they did inhibit Gram-positive bacteria.

Supplementary material

248_2011_9840_MOESM1_ESM.pdf (104 kb)
Fig. S1Cluster analysis of physiological data from Table 2 (a), API ZYM (b), and Biolog GN2 (c) results from Duganella spp. from wild and cultivated olives. The UPGMA algorithm was applied to the similarity matrix generated from each experiment by using the Dice (binary, Table 2 data, a) or pairwise Pearson’s product-moment correlation coefficient (API ZYM and Biolog data; b, c). Values on the nodes indicated the bootstrap support (PDF 104 kb)
248_2011_9840_MOESM2_ESM.doc (56 kb)
Table S1(DOC 56.5 kb)

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Sergio Aranda
    • 1
  • Miguel Montes-Borrego
    • 1
  • Blanca B. Landa
    • 1
  1. 1.Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC)CórdobaSpain

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