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Microorganisms

Title:		Olea europaea L. Root Endophyte Bacillus velezensis OEE1 Counteracts Oomycete and Fungal Harmful Pathogens and Harbours a Large Repertoire of Secreted and Volatile Metabolites and Beneficial Functional Genes
Author(s):		Cheffi M; Bouket AC; Alenezi FN; Luptakova L; Belka M; Vallat A; Rateb ME; Tounsi S; Triki MA; Belbahri L;
Address:		"Institut de l'Olivier Sfax, Sfax 3000, Tunisia. cheffimanel@gmail.com. Plant Protection Research Department, East Azarbaijan Agricultural and Natural Resources Research and Education Center, AREEO, Tabriz 5355179854, Iran. a.chenari@areeo.ac.ir. NextBiotech, 98 Rue Ali Belhouane, 3030 Agareb, Tunisia. Dr-Faizah@outlook.com. NextBiotech, 98 Rue Ali Belhouane, 3030 Agareb, Tunisia. Lenka.Luptakova@uvlf.sk. Department of Biology and Genetics, Institute of Biology, Zoology and Radiobiology, University of Veterinary Medicine and Pharmacy in Kosice, 04181 Kosice, Slovakia. Lenka.Luptakova@uvlf.sk. Department of Forest Pathology, Poznan University of Life Sciences, Wojska Polskiego 71c, 60-628 Poznan, Poland. marta.belka@up.poznan.pl. Department of Plant and Soil Science, Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, Aberdeen AB24 3UU, UK. marta.belka@up.poznan.pl. Neuchatel Platform of Analytical Chemistry, Institute of Chemistry, University of Neuchatel, 2000 Neuchatel, Switzerland. armelle.vallat@unine.ch. School of Computing, Engineering & Physical Sciences, University of the West of Scotland, Paisley PA1 2BE, UK. Mostafa.Rateb@uws.ac.uk. Laboratory of Biopesticides, Centre of Biotechnology of Sfax, Sfax 3000, Tunisia. slim.tounsi@cbs.rnrt.tn. Institut de l'Olivier Sfax, Sfax 3000, Tunisia. slim.tounsi@cbs.rnrt.tn. NextBiotech, 98 Rue Ali Belhouane, 3030 Agareb, Tunisia. lassaad.belbahri@unine.ch. Laboratory of Soil Biodiversity, University of Neuchatel, 2000 Neuchatel, Switzerland. lassaad.belbahri@unine.ch"
Journal Title:		Microorganisms
Year:		2019
Volume:		20190903
Issue:		9
Page Number:		-
DOI:		10.3390/microorganisms7090314
ISSN/ISBN:		2076-2607 (Print) 2076-2607 (Electronic) 2076-2607 (Linking)
Abstract:		"Oomycete and fungal pathogens, mainly Phytophthora and Fusarium species, are notorious causal agents of huge economic losses and environmental damages. For instance, Phytophthora ramorum, Phytophthora cryptogea, Phytophthora plurivora and Fusarium solani cause significant losses in nurseries and in forest ecosystems. Chemical treatments, while harmful to the environment and human health, have been proved to have little or no impact on these species. Recently, biocontrol bacterial species were used to cope with these pathogens and have shown promising prospects towards sustainable and eco-friendly agricultural practices. Olive trees prone to Phytophthora and Fusarium disease outbreaks are suitable for habitat-adapted symbiotic strategies, to recover oomycetes and fungal pathogen biocontrol agents. Using this strategy, we showed that olive trees-associated microbiome represents a valuable source for microorganisms, promoting plant growth and healthy benefits in addition to being biocontrol agents against oomycete and fungal diseases. Isolation, characterization and screening of root microbiome of olive trees against numerous Phytophthora and other fungal pathogens have led to the identification of the Bacillus velezensis OEE1, with plant growth promotion (PGP) abilities and strong activity against major oomycete and fungal pathogens. Phylogenomic analysis of the strain OEE1 showed that B. velezensis suffers taxonomic imprecision that blurs species delimitation, impacting their biofertilizers' practical use. Genome mining of several B. velezensis strains available in the GenBank have highlighted a wide array of plant growth promoting rhizobacteria (PGPR) features, metals and antibiotics resistance and the degradation ability of phytotoxic aromatic compounds. Strain OEE1 harbours a large repertoire of secreted and volatile secondary metabolites. Rarefaction analysis of secondary metabolites richness in the B. velezenis genomes, unambiguously documented new secondary metabolites from ongoing genome sequencing efforts that warrants more efforts in order to assess the huge diversity in the species. Comparative genomics indicated that B. velezensis harbours a core genome endowed with PGP features and accessory genome encoding diverse secondary metabolites. Gas Chromatography-Mass Spectrometry (GC-MS) analysis of OEE1 Volatile Organic Compounds (VOCs) and Liquid Chromatography High Resolution Mas Spectrometry (LC-HRMS) analysis of secondary metabolites identified numerous molecules with PGP abilities that are known to interfere with pathogen development. Moreover, B. velezensis OEE1 proved effective in protecting olive trees against F. solani in greenhouse experiments and are able to inhabit olive tree roots. Our strategy provides an effective means for isolation of biocontrol agents against recalcitrant pathogens. Their genomic analysis provides necessary clues towards their efficient implementation as biofertilizers"
Keywords:		Bacillus velezensis Fusarium solani abiotic stress antimicrobial activity endophytes plant growth promoting bacteria secondary metabolites;
Notes:		"PubMed-not-MEDLINECheffi, Manel Bouket, Ali Chenari Alenezi, Faizah N Luptakova, Lenka Belka, Marta Vallat, Armelle Rateb, Mostafa E Tounsi, Slim Triki, Mohamed Ali Belbahri, Lassaad eng Switzerland 2019/09/06 Microorganisms. 2019 Sep 3; 7(9):314. doi: 10.3390/microorganisms7090314"