title: Dynamics in the Strawberry Rhizosphere Microbiome in Response to Biochar andBotrytis cinereaLeaf Infection.
abstract: Adding biochar, the solid coproduct of biofuel production, to peat can enhance strawberry growth, and disease resistance against the airborne fungal pathogenBotrytis cinerea. Additionally, biochar can induce shifts in the strawberry rhizosphere microbiome. However, the moment that this biochar-mediated shift occurs in the rhizosphere is not known. Further, the effect of an above-ground infection on the strawberry rhizosphere microbiome is unknown. In the present study we established two experiments in which strawberry transplants (cv. Elsanta) were planted either in peat or in peat amended with 3% biochar. First, we established a time course experiment to measure the effect of biochar on the rhizosphere bacterial and fungal communities over time. In a second experiment, we inoculated the strawberry leaves withB. cinerea, and studied the impact of the infection on the rhizosphere bacterial community. The fungal rhizosphere community was stabilized after 1 week, except for the upcoming Auriculariales, whereas the bacterial community shifted till 6 weeks. An effect of the addition of biochar to the peat on the rhizosphere microbiome was solely measured for the bacterial community from week 6 of plant growth onwards. When scoring the plant development, biochar addition was associated with enhanced root formation, fruit production, and postharvest resistance of the fruits againstB. cinerea. We hypothesize that the bacterial rhizosphere microbiome, but also biochar-mediated changes in chemical substrate composition could be involved in these events. Infection of the strawberry leaves withB. cinereainduced shifts in the bacterial rhizosphere community, with an increased bacterial richness. This disease-induced effect was not observed in the rhizospheres of theB. cinerea-infected plants grown in the biochar-amended peat. The results show that an above-ground infection has its effect on the strawberry rhizosphere microbiome, changing the bacterial interactions in the root-substrate interface. This infection effect on the bacterial rhizosphere microbiome seems to be comparable to, but less pronounced than the effect of biochar-addition to the peat. The biological meaning of these observations needs further research, but this study indicates that biochar and an above-ground pathogen attack help the plant to recruit rhizosphere microbes that may aid them in their plant growth and health.
authors.affiliation: Plant Sciences Unit, Crop Protection, Institute of Agricultural and Fisheries ResearchMerelbeke, Belgium; Department of Applied Mathematics Computer Sciences and Statistics, Ghent UniversityGhent, Belgium.
authors.forename: Caroline
authors.initials: C
authors.lastname: De Tender
authors.affiliation: Plant Sciences Unit, Crop Protection, Institute of Agricultural and Fisheries Research Merelbeke, Belgium.
authors.forename: Annelies
authors.initials: A
authors.lastname: Haegeman
authors.affiliation: Plant Sciences Unit, Crop Husbandry and Environment, Institute of Agricultural and Fisheries Research Merelbeke, Belgium.
authors.forename: Bart
authors.initials: B
authors.lastname: Vandecasteele
authors.affiliation: Department of Applied Mathematics Computer Sciences and Statistics, Ghent UniversityGhent, Belgium; Bioinformatics Institute Ghent From Nucleotides to Networks, Ghent UniversityGhent, Belgium.
authors.forename: Lieven
authors.initials: L
authors.lastname: Clement
authors.affiliation: Plant Sciences Unit, Crop Protection, Institute of Agricultural and Fisheries ResearchMerelbeke, Belgium; Plant Sciences Unit, Crop Husbandry and Environment, Institute of Agricultural and Fisheries ResearchMerelbeke, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Cremelie
authors.affiliation: Department of Applied Mathematics Computer Sciences and Statistics, Ghent University Ghent, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Dawyndt
authors.affiliation: Plant Sciences Unit, Crop Protection, Institute of Agricultural and Fisheries Research Merelbeke, Belgium.
authors.forename: Martine
authors.initials: M
authors.lastname: Maes
authors.affiliation: Plant Sciences Unit, Crop Protection, Institute of Agricultural and Fisheries Research Merelbeke, Belgium.
authors.forename: Jane
authors.initials: J
authors.lastname: Debode
keywords: above-ground infection; bacteria; biochar; fungi; plant growth; rhizosphere