Temporal shifts in endophyte bacterial community composition of sessile oak (Quercus petraea) are linked to foliar nitrogen, stomatal length, and herbivory.

Luigimaria Borruso,Sara Casagrande Bacchiocchi,Alessia Bani,Lorenzo Brusetti,Camilla Wellstein,Rita Tonin,Ania Margoni,Stefan Zerbe

doi:10.7717/peerj.5769

Luigimaria Borruso, Sara Casagrande Bacchiocchi + Show 6 more

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https://doi.org/10.7717/peerj.5769

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Journal: PeerJ	Publication Date: Oct 12, 2018
Citations: 9	License type: CC BY 4.0

Affiliation: Free University of Bozen-Bolzano

Abstract

We studied the relationship between plant functional foliar traits and the endophytic bacterial communities associated in trees, taking the example of sessile oak (Quercus petraea (Matt.) Liebl). Forty-five samples with replicates of eight leaves per sample were collected in spring, summer and autumn. Bacterial community diversity was analyzed via Automated Ribosomal Intergenic Spacer Analysis (ARISA). The leaf traits specific leaf area, level of herbivory, stomatal number, stomatal length, carbon and nitrogen concentration were measured for the leaves of each sample. For statistical analysis, linear mixed effect models, the Canonical Correlation Analysis (CCA) and Non-Parametric Multivariate Analysis of Variance (NPMANOVA) were applied. Herbivory, nitrogen and carbon concentration were significantly different in autumn compared to spring and summer (p value < 0.05), while stomatal length was differentiated between spring and the other two seasons (p value < 0.01). The seasonal differentiation of the bacterial community structure was explained by the first and second axes (29.7% and 25.3%, respectively) in the CCA. The bacterial community structure significantly correlated with herbivory, nitrogen concentration and stomatal length. We conclude that herbivory, nitrogen content, and size of stomatal aperture at the leaf level are important for endophyte colonization in oaks growth in alpine forest environments.

Highlights

One of the major interfaces of biological interaction is between microbiota and plants
Regarding which taxa contribute to the observed difference between seasons, even if the attribution of single Automated Ribosomal Intergenic Spacer Analysis (ARISA) peaks to specific taxa cannot be conclusive due to the real possibility that a peak could be represented by several taxa from different phyla, a putative raw taxon attribution could be done
In order to shed light on the processes behind community changes, we explored the role of leaf functional traits in bacterial structure dynamics

Summary

Introduction

One of the major interfaces of biological interaction is between microbiota and plants. While many integrative studies exist, regarding description of bacterial taxa related to host plants and linking bacterial and plant communities across different spatial scales (e.g., symbiosis), temporal scales remain less unexplored. Plant functional traits are increasingly used in ecological research and are a promising avenue to link plant characteristics to environmental factor in interdisciplinary researches (Cornwell et al, 2008; Wellstein et al, 2011). How to cite this article Borruso et al (2018), Temporal shifts in endophyte bacterial community composition of sessile oak (Quercus petraea) are linked to foliar nitrogen, stomatal length, and herbivory. In the context of the leaf environment of deciduous trees and inhabiting endophytic bacteria, intra-annual dynamics are of special interest

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