Diversity of rhizosphere and endophytic fungi in Atractylodes macrocephala during continuous cropping.

Bo Zhu,Qiaoyan Zhang,Jiayan Yu,Shihui Dong,Qingyong Ji,Luping Qin,Wei Wu,Jianjun Wu

doi:10.7717/peerj.8905

Abstract

Rhizospheric and endophytic fungi are key factors which influence plant fitness and soil fertility. Atractylodes macrocephala is one of the best-known perennial herbs used in traditional Chinese medicine. Continuous cropping has been shown to have a negative effect on its growth and renders it more susceptible to microbial pathogen attacks. In this study, we investigated the effects of continuous cropping on the endophytic and rhizospheric fungi associated with A. macrocephala using culture-independent Illumina MiSeq. Continuous cropping was found to decrease fungal diversity inside plant roots, stems, leaves and tubers. Additionally, we found that the structure and diversity of rhizospheric and endophytic fungal communities were altered by root-rot disease. Fusarium was overrepresented among root-rot rhizospheric and endophytic fungi, indicating that it has a major negative impact on plant health during A. macrocephala monocropping. Canonical correspondence analysis of the control and diseased samples revealed that pH, hydrolysis N, electrical conductivity and Hg content were well-correlated with fungal community composition during continuous cropping. Taken together, these results highlight the ecological significance of fungal communities in maintaining plant fitness and will guide the development strategies to attenuate the negative impacts of A. macrocephala continuous cropping.

Highlights

Plants and rhizospheric soil are colonized by fungal communities that can impact their fitness by influencing nutrient acquisition, causing soil-borne diseases and affecting the activity of plant pathogens (Tan et al, 2017a)
Electrical conductivity, total P, total K, hydrolysis N, available P, and available K contents were much higher in the continuous cropping soil relative to the S_CK, while organic matter and total N contents were higher in the S_CK than in continuous cropping soil samples
Electrical conductivity is associated with soil salinity and our results suggest it may be an important predictor of fungal community compositions in continuous cropping soils of A. macrocephala

Summary

Introduction

Plants and rhizospheric soil are colonized by fungal communities that can impact their fitness by influencing nutrient acquisition, causing soil-borne diseases and affecting the activity of plant pathogens (Tan et al, 2017a). Many previous studies have shown that studying plant-microorganism interactions can lead to improvements in several agronomic processes, including crop rotation and tillage (Somenahally et al, 2018), pesticide application (Regar et al, 2019), irrigation (Dang et al, 2019), fertilizer application (Nguyen et al, 2018) and continuous cropping (Ali et al, 2019; Xiong et al, 2015). Diversity of rhizosphere and endophytic fungi in Atractylodes macrocephala during continuous cropping. Studies have shown that continuous cropping leads to compromised growth, yield loss, disease susceptibility and quality deterioration (Hontoria et al, 2019). The detrimental effects of continuous cropping have been demonstrated in a variety of crop species, including Atractylodes macrocephala (Zheng et al, 2018)

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