title: The genome analysis of Candidatus Burkholderia crenata reveals that secondary metabolism may be a key function of the Ardisia crenata leaf nodule symbiosis.
abstract: A majority of Ardisia species harbour Burkholderia sp. bacteria within specialized leaf nodules. The bacteria are transmitted hereditarily and have not yet been cultured outside of their host. Because the plants cannot develop beyond the seedling stage without their symbionts, the symbiosis is considered obligatory. We sequenced for the first time the genome of Candidatus Burkholderia crenata (Ca. B. crenata), the leaf nodule symbiont of Ardisia crenata. The genome of Ca. B. crenata is the smallest Burkholderia genome to date. It contains a large amount of insertion sequences and pseudogenes and displays features consistent with reductive genome evolution. The genome does not encode functions commonly associated with plant symbioses such as nitrogen fixation and plant hormone metabolism. However, we identified unique genes with a predicted role in secondary metabolism in the genome of Ca. B. crenata. Specifically, we provide evidence that the bacterial symbionts are responsible for the synthesis of compound FR900359, a cyclic depsipeptide with biomedical properties previously isolated from leaves of A. crenata.
authors.affiliation: Department of Microbiology, University of Zurich, CH-8008, Zurich, Switzerland.|Department of Microbiology, University of Ghent, 9000, Gent, Belgium.
authors.forename: Aurelien
authors.initials: A
authors.lastname: Carlier
authors.affiliation: Department of Microbiology, University of Zurich, CH-8008, Zurich, Switzerland.
authors.forename: Linda
authors.initials: L
authors.lastname: Fehr
authors.affiliation: Department of Microbiology, University of Zurich, CH-8008, Zurich, Switzerland.
authors.forename: Marta
authors.initials: M
authors.lastname: Pinto-Carbó
authors.affiliation: Institute for Pharmaceutical Biology, University of Bonn, 53115, Bonn, Germany.
authors.forename: Till
authors.initials: T
authors.lastname: Schäberle
authors.affiliation: Institute for Pharmaceutical Biology, University of Bonn, 53115, Bonn, Germany.
authors.forename: Raphael
authors.initials: R
authors.lastname: Reher
authors.affiliation: Plant Conservation and Population Biology, KU Leuven, 3001, Leuven, Belgium.|National Botanic Garden of Belgium, 1860, Meise, Belgium.
authors.forename: Steven
authors.initials: S
authors.lastname: Dessein
authors.affiliation: Institute for Pharmaceutical Biology, University of Bonn, 53115, Bonn, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: König
authors.affiliation: Department of Microbiology, University of Zurich, CH-8008, Zurich, Switzerland.
authors.forename: Leo
authors.initials: L
authors.lastname: Eberl
mesh_terms: D031644:Ardisia / Q000378:metabolism* / Q000382:microbiology*; D001483:Base Sequence; D005075:Biological Evolution; D001692:Biological Transport / Q000235:genetics; D019117:Burkholderia / Q000145:classification / Q000235:genetics*; D050260:Carbohydrate Metabolism / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D047630:Depsipeptides / Q000096:biosynthesis*; D016680:Genome, Bacterial / Q000235:genetics; D018515:Plant Leaves / Q000382:microbiology*; D064210:Secondary Metabolism / Q000235:genetics; D036226:Seedlings; D017422:Sequence Analysis, DNA; D013559:Symbiosis / Q000235:genetics / Q000502:physiology
chemical_list: D004269:DNA, Bacterial; D047630:Depsipeptides; C000607068:FR900359