Secondary metabolites produced by Microbacterium sp. LGMB471 with antifungal activity against the phytopathogen Phyllosticta citricarpa

• Published in: Folia microbiologica Vol. 64; no. 3; pp. 453 - 460
• Main Authors: Savi, Daiani Cristina, Shaaban, Khaled A., Gos, Francielly M. W., Thorson, Jon S., Glienke, Chirlei, Rohr, Jürgen
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.05.2019; Springer Nature B.V
• Subjects: Actinomycetales - chemistry; Actinomycetes; Antifungal activity; Antifungal agents; antifungal properties; Applied Microbiology; Ascomycota - drug effects; Asia; Biomedical and Life Sciences; Black spot; Brazil; Central America; Citrus; Citrus - microbiology; citrus black spot; Citrus fruits; Conidia; crops; Culture Media; Daidzein; Data processing; diketopiperazines; Diketopiperazines - isolation & purification; Diketopiperazines - pharmacology; Disease control; ecosystems; Endophytes; Environmental Engineering/Biotechnology; European Union; fruit diseases; Fruits; Fungicides; Fungicides, Industrial - isolation & purification; Fungicides, Industrial - pharmacology; Genistein; Guignardia citricarpa; Immunology; Isoflavones; Isoflavones - isolation & purification; Isoflavones - pharmacology; leaves; Lesions; Life Sciences; Medicinal plants; Metabolites; Microbacterium; Microbial Sensitivity Tests; Microbiology; Minimum inhibitory concentration; Original Article; Pantanal; Pesticides; Phyllosticta citricarpa; Plant Diseases - microbiology; Plant Leaves - microbiology; plant pathogens; quarantine; Quarantine regulations; Reproduction (biology); Secondary Metabolism; Secondary metabolites; Sexual reproduction; South America; Spores; Spores, Fungal - drug effects; subtropics; temperature; United States; Vochysia; Brazil; Asia; United States; Pantanal; South America; Central America
• ISSN: 0015-5632; 1874-9356; 1874-9356
• DOI: 10.1007/s12223-018-00668-x

The citrus black spot (CBS), caused by Phyllosticta citricarpa , is one of the most important citrus diseases in subtropical regions of Africa, Asia, Oceania, and the Americas, and fruits with CBS lesions are still subject to quarantine regulations in the European Union. Despite the high application of fungicides, the disease remains present in the citrus crops of Central and South America. In order to find alternatives to help control CBS and reduce the use of fungicides, we explored the antifungal potential of endophytic actinomycetes isolated from the Brazilian medicinal plant Vochysia divergens found in the Pantanal biome. Two different culture media and temperatures were selected to identify the most efficient conditions for the production of active secondary metabolites. The metabolites produced by strain Microbacterium sp. LGMB471 cultured in SG medium at 36 °C considerably inhibited the development of P. citricarpa . Three isoflavones and five diketopiperazines were identified, and the compounds 7- O -β- d -glucosyl-genistein and 7- O -β- d -glucosyl-daidzein showed high activity against P. citricarpa , with the MIC of 33 μg/mL and inhibited the production of asexual spores of P. citricarpa on leaves and citrus fruits. Compounds that inhibit conidia formation may be a promising alternative to reduce the use of fungicides in the control of CBS lesions, especially in regions where sexual reproduction does not occur, as in the USA. Our data suggest the use of Microbacterium sp. LGMB471 or its metabolites as an ecological alternative to be used in association with the fungicides for the control of CBS disease.