Physiological change alters endophytic bacterial community in clubroot of tumorous stem mustard infected by Plasmodiophora brassicae

Diandong Wang,Limei Pan,Tingting Sun,Xueliang Tian,Songyu Zhao,Hongfang Liu

doi:10.1186/s12866-020-01930-4

Diandong Wang, Limei Pan + Show 4 more

Open Access

https://doi.org/10.1186/s12866-020-01930-4

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Abstract

BackgroundEndophytic bacteria are considered as symbionts living within plants and are influenced by abiotic and biotic environments. Pathogen cause biotic stress, which may change physiology of plants and may affect the endophytic bacterial communiy. Here, we reveal how endophytic bacteria in tumorous stem mustard (Brassica juncea var. tumida) are affected by plant physiological changes caused by Plasmodiophora brassicae using 16S rRNA high-throughput sequencing.ResultsThe results showed that Proteobacteria was the dominant group in both healthy roots and clubroots, but their abundance differed. At the genus level, Pseudomonas was dominant in clubroots, whereas Rhodanobacter was the dominant in healthy roots. Hierarchical clustering, UniFrac-weighted principal component analysis (PCA), non-metric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM) indicated significant differences between the endophytic bacterial communities in healthy roots and clubroots. The physiological properties including soluble sugar, soluble protein, methanol, peroxidase (POD) and superoxide dismutase (SOD) significantly differed between healthy roots and clubroots. The distance-based redundancy analysis (db-RDA) and two-factor correlation network showed that soluble sugar, soluble protein and methanol were strongly related to the endophytic bacterial community in clubroots, whereas POD and SOD correlated with the endophytic bacterial community in healthy roots.ConclusionsOur results illustrate that physiologcial changes caused by P. brassicae infection may alter the endophytic bacterial community in clubroots of tumorous stem mustard.

Highlights

Endophytic bacteria are considered as symbionts living within plants and are influenced by abiotic and biotic environments
It is well known that endophytic bacteria are beneficial to plant growth and development because they synthesize plant hormones, solubilize phosphate and promote plant tolerance to biotic and abiotic stresses [3,4,5] by producing siderophores, competing with pathogens for space and nutrients, and modulating the plant resistance response [6, 7]
The endophytic bacterial community in grapevine and apple infected by phytoplasmas [12, 13] and in tomato infected by root knot nematode [14] changed compared with healthy plants

Summary

Introduction

Endophytic bacteria are considered as symbionts living within plants and are influenced by abiotic and biotic environments. Pathogen cause biotic stress, which may change physiology of plants and may affect the endophytic bacterial communiy. It is well known that endophytic bacteria are beneficial to plant growth and development because they synthesize plant hormones (indole3-acetic acid), solubilize phosphate and promote plant tolerance to biotic and abiotic stresses [3,4,5] by producing siderophores, competing with pathogens for space and nutrients, and modulating the plant resistance response [6, 7]. Endophytic bacteria often live in plant intercellular spaces, where they absorb carbohydrates, amino acids, and inorganic nutrients [8, 10, 11]. When endophytic bacteria survive in the intracellular environment, they must adapt to that environment and be compatible with a host. Pathogens in infected plants would compete with endophytic bacteria for space and nutrients. Which physiological changes may modify endophytic bacteria and how is unclear

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