Spatial Distribution of the Pepper Blight (Phytophthora capsici) Suppressive Microbiome in the Rhizosphere.

Huixiu Li,Guo-Chun Ding,Ning Wang,Xiaoyan Ding,Yingjie Liu,Jia Ding,Ji Li,Yuquan Wei

doi:10.3389/fpls.2021.748542

Huixiu Li, Guo-Chun Ding + Show 6 more

Open Access

https://doi.org/10.3389/fpls.2021.748542

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Abstract

The properties of plant rhizosphere are dynamic and heterogeneous, serving as different habitat filters for or against certain microorganisms. Herein, we studied the spatial distribution of bacterial communities in the rhizosphere of pepper plants treated with a disease-suppressive or non-suppressive soil. The bacterial richness was significantly (p < 0.05) higher in plants treated with the disease-suppressive soil than in those treated with the non-suppressive soil. Bacterial richness and evenness greatly differed between root parts, with decrease from the upper taproot to the upper fibrous root, the lower taproot, and the lower fibrous root. As expected, the bacterial community in the rhizosphere differed between suppressive and non-suppressive soil. However, the spatial variation (36%) of the bacterial community in the rhizosphere was much greater than that explained by soils (10%). Taxa such as subgroups of Acidobacteria, Nitrosospira, and Nitrospira were known to be selectively enriched in the upper taproot. In vitro Bacillus antagonists against Phytophthora capsici were also preferentially colonized in the taproot, while the genera such as Clostridium, Rhizobium, Azotobacter, Hydrogenophaga, and Magnetospirillum were enriched in the lower taproot or fibrous root. In conclusion, the spatial distribution of bacterial taxa and antagonists in the rhizosphere of pepper sheds light on our understanding of microbial ecology in the rhizosphere.

Highlights

The abundance and diversity of microorganisms that inhabit the rhizosphere of plants play key roles in maintaining plant nutrients and health (Berg and Smalla, 2009; Mendes et al, 2011, 2013; Faria et al, 2020; Yu et al, 2020)
We focused on two main questions: (1) What is the spatial distribution of the bacterial community and the antagonists in the rhizosphere of peppers plants? (2) To which level such spatial distributions might be influenced by different soil microbiomes?
The bacterial richness was significantly (p < 0.05) higher in plants treated with the diseasessuppressive soil than in those treated with the non-suppressive soil (Figure 1B)

Summary

Introduction

The abundance and diversity of microorganisms that inhabit the rhizosphere of plants play key roles in maintaining plant nutrients and health (Berg and Smalla, 2009; Mendes et al, 2011, 2013; Faria et al, 2020; Yu et al, 2020). Rhizospheric microbiomes may increase crop nutrients acquisition and resistance to environmental stresses (Ahkami et al, 2017), decreasing the excessive use of chemical fertilizers or pesticides. Several biotic and abiotic factors, such as plant species and development (Bell et al, 2015; Ma et al, 2019), soil animals (Jiang et al, 2017), viruses (Pratama et al, 2020), inoculation of microbial consortia (Zhang et al, 2019), invasion of pathogens (Yin et al, 2021), land use (Wang C. et al, 2021), fertilization (Ding et al, 2020), and tillage (Li et al, 2021), may cause changes in the composition and functions of microbial communities inhabiting the rhizosphere. The interactions among rhizospheric microorganisms may influence the recruitment of beneficial plant microorganisms (Tao et al, 2020)

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