title: AnIn vitroStudy of Bio-Control and Plant Growth Promotion Potential of Salicaceae Endophytes.
abstract: Microbial communities in the endosphere of Salicaceae plants, poplar (Populus trichocarpa) and willow (Salix sitchensis), have been demonstrated to be important for plant growth promotion, protection from biotic and abiotic stresses, and degradation of toxic compounds. Our study aimed to investigate bio-control activities of Salicaceae endophytes against various soil borne plant pathogens includingRhizoctonia solaniAG-8,Fusarium culmorum, Gaeumannomyces graminisvar.tritici, andPythium ultimum. Additionally, different plant growth promoting traits such as biological nitrogen fixation (BNF), indole-3-acetic acid (IAA) biosynthesis, phosphate solubilization, and siderophore production were assessed in all bio-control positive strains.Burkholderia, Rahnella, Pseudomonas, andCurtobacteriumwere major endophyte genera that showed bio-control activities in thein-vitroassays. The bio-control activities ofBurkholderiastrains were stronger across all tested plant pathogens as compared to other stains. Genomes of sequencedBurkholderiastrains WP40 and WP42 were surveyed to identify the putative genes involved in the bio-control activities. TheocfandhcnABCgene clusters responsible for biosynthesis of the anti-fungal metabolites, occidiofungin and hydrogen cyanide, are present in the genomes of WP40 and WP42. Nearly all endophyte strains showing the bio-control activities produced IAA, solubilized tricalcium phosphate, and synthesized siderophores in the culture medium. Moreover, some strains reduced acetylene into ethylene in the acetylene reduction assay, a common assay used for BNF. Salicaceae endophytes could be useful for bio-control of various plant pathogens, and plant growth promotion possibly through the mechanisms of BNF, IAA production, and nutrient acquisition.
authors.affiliation: School of Environmental and Forest Sciences, College of the Environment, University of Washington Seattle, WA, USA.
authors.forename: Shyam L
authors.initials: SL
authors.lastname: Kandel
authors.affiliation: Department for Innovation in Biological, Agro-Food and Forest Systems, University of Tuscia Viterbo, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Firrincieli
authors.affiliation: Department of Biology, University of Washington Seattle, WA, USA.
authors.forename: Pierre M
authors.initials: PM
authors.lastname: Joubert
authors.affiliation: Wheat Health, Genetics and Quality Research Unit, USDA-ARS Pullman, WA, USA.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Okubara
authors.affiliation: Department of Plant Pathology, Washington State University Pullman, WA, USA.
authors.forename: Natalie D
authors.initials: ND
authors.lastname: Leston
authors.affiliation: Department of Plant Pathology, Washington State University Pullman, WA, USA.
authors.forename: Kendra M
authors.initials: KM
authors.lastname: McGeorge
authors.affiliation: Department for Innovation in Biological, Agro-Food and Forest Systems, University of Tuscia Viterbo, Italy.
authors.forename: Giuseppe S
authors.initials: GS
authors.lastname: Mugnozza
authors.affiliation: Department for Innovation in Biological, Agro-Food and Forest Systems, University of Tuscia Viterbo, Italy.
authors.forename: Antoine
authors.initials: A
authors.lastname: Harfouche
authors.affiliation: School of Environmental and Forest Sciences, College of the Environment, University of Washington Seattle, WA, USA.
authors.forename: Soo-Hyung
authors.initials: SH
authors.lastname: Kim
authors.affiliation: School of Environmental and Forest Sciences, College of the Environment, University of Washington Seattle, WA, USA.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Doty
keywords: Burkholderia; Salicaceae endophytes; bio-control; soil borne plant pathogens