title: Streptomyces araujoniae Produces a Multiantibiotic Complex with Ionophoric Properties to Control Botrytis cinerea.
abstract: A recently described actinomycete species (Streptomyces araujoniae ASBV-1(T)) is effective against many phytopathogenic fungi. In this study, we evaluated the capacity of this species to inhibit Botrytis cinerea development in strawberry pseudofruit, and we identified the chemical structures of its bioactive compounds. An ethyl acetate crude extract (0.1 mg ml(-1)) of ASBV-1(T) fermentation broth completely inhibited fungus growth in strawberry pseudofruit under storage conditions. The crude extract was fractionated by preparative high-performance liquid chromatography; the active fraction was further evaluated by tandem mass spectrometry. ASBV-1(T) produced a multiantibiotic complex with ionophoric properties. This complex contained members of the macrotetralides class (including monactin, dinactin, trinactin, and tetranactin) and the cyclodepsipeptide valinomycin, all of which were active against B. cinerea. Furthermore, the addition of 2 mM MgSO4 and 1 mM ZnSO4 enhanced macrotetralide and valinomycin production, respectively, in the culture broth. These compounds are considered to be the main active molecules that S. araujoniae produces to control B. cinerea. Their low to moderate toxicity to humans and the environment justifies the application of ASBV-1(T) in biological control programs that aim to mitigate the damage caused by this phytopathogen.
authors.forename: Leonardo José
authors.initials: LJ
authors.lastname: Silva
authors.forename: Eduardo José
authors.initials: EJ
authors.lastname: Crevelin
authors.forename: Wallace Rafael
authors.initials: WR
authors.lastname: Souza
authors.forename: Luiz Alberto Beraldo
authors.initials: LA
authors.lastname: Moraes
authors.forename: Itamar Soares
authors.initials: IS
authors.lastname: Melo
authors.forename: Tiago Domingues
authors.initials: TD
authors.lastname: Zucchi
mesh_terms: D000085:Acetates; D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D020171:Botrytis / Q000187:drug effects*; D031985:Fragaria / Q000382:microbiology*; D005638:Fruit / Q000382:microbiology; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000382:microbiology / Q000517:prevention & control*; D013302:Streptomyces / Q000737:chemistry* / Q000302:isolation & purification / Q000502:physiology
chemical_list: D000085:Acetates; D000890:Anti-Infective Agents; C007650:ethyl acetate