|Van Horn, Christopher|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 6/3/2019
Publication Date: 12/12/2019
Citation: Van Horn, C.R., Mazzola, M. 2019. Apple rootstock genotype influences endophyte and rhizosphere microbial community. Phytopathology. 109(11):S3.2.
Technical Abstract: Apple replant disease (ARD) negatively impacts tree health and productivity in new orchard plantings. Use of disease tolerant rootstocks can diminish growth limiting effects of ARD, however the effect of rootstock genotype on modulating the endophytic and rhizosphere microbiome enabling ARD tolerance is not understood. In this study a series of tolerant and susceptible rootstock cultivars were consecutively planted into orchard replant soil containing a known pathogen complex. Growth measurements, rhizosphere soil and root samples were taken over time. Amplicon sequencing was used to determine simultaneously a broad taxonomic range of organisms and their abundances. T-RFLP data indicated that rootstocks G.41 and G.890 recruit dissimilar rhizosphere bacterial communities from each other and the M.9 and M.26 rootstocks. Endophytic and rhizosphere microbial communities differed for all rootstocks. Several genera known to form ectomycorrhizal associations with other plants were identified as apple root endophytes for the first time in this study. Furthermore, VAM fungal genera represented >20% of OTUs in G.890, G.935 and M.9 endophytic communities. Results from this study will have broad implications for providing guidance to apple rootstock breeding programs in selecting desired traits for soil biotic adaptations. Differences in composition of microbial communities during early stages of rootstock growth may offer insight into ARD tolerance and disease development.