Control of Fusarium wilt by wheat straw is associated with microbial network changes in watermelon rhizosphere

Lili Tang,Jinming Kou,Kai Pan,Fengzhi Wu,Wenhui Li,Chao Fan,Ye Xia

doi:10.1038/s41598-020-69623-6

Abstract

Straw return is an effective strategy to alleviate soil-borne diseases. Though watermelon Fusarium wilt is a severe soil-borne disease, the effect of wheat straw on the disease remains unclear. Thus, we investigated the effects of wheat straw on soil bacterial and fungal communities by adding wheat straw to consecutive watermelon soil in the greenhouse condition. The microbiome changes were further investigated using network analysis based on 16S rDNA and internal transcribed spacer deep sequencing. Wheat straw addition increased the fungal community diversity, whereas the bacterial diversity was not affected. Compared to the control group, the relative abundance of some bacteria, including Actinobacteria, Chloroflexi, and Saccharibacteria, was increased with wheat straw addition. For fungi, the relative abundance of Fusarium was decreased with wheat straw addition. Microbial network analysis demonstrated that the fungal community has a more complex connection than the bacterial community. In addition, redundancy analysis indicated that the Fusarium genera were significantly related to the disease index. Taken together, the addition of wheat straw might affect the microbial community through increasing the relative abundance of phylum Actinobacteria, decreasing the relative abundance of Fusarium, and increasing the fungal network complexity to enhance the defense of watermelon against Fusarium wilt disease.

Highlights

Straw return is an effective strategy to alleviate soil-borne diseases
Wheat straw addition significantly increased the relative abundances of Actinobacteria, Chloroflexi, and Saccharibacteria, while significantly decreasing the relative abundance of Parcubacteria at both moments of sampling (P < 0.05) in the consecutive watermelon monoculture system
Our results showed that wheat straw addition could increase the relative abundance of Chloroflexi, Saccharibacteria, and Schizothecium, but reduce the relative abundance of the pathogen Fusarium

Summary

Introduction

Straw return is an effective strategy to alleviate soil-borne diseases. Though watermelon Fusarium wilt is a severe soil-borne disease, the effect of wheat straw on the disease remains unclear. The addition of wheat straw might affect the microbial community through increasing the relative abundance of phylum Actinobacteria, decreasing the relative abundance of Fusarium, and increasing the fungal network complexity to enhance the defense of watermelon against Fusarium wilt disease. Continuous cropping monoculture reduces soil microbial diversity, increases the accumulation of pathogens, and aggravates the occurrence of plant diseases[3]. Alteration of the soil microbial community structure had been identified as the key factor that leads to the accumulation of fungal pathogens under the continuous cropping monoculture system[3]. Network analysis by Shen et al.[15] revealed that the number of years of continuous monoculture cropping changed the microbial dominance from bacteria to fungi and from cooperative to competitive interactions. Network analysis could add substantial dimensions and provide insights into the combination of microorganisms for better understanding of the complex interactions among soil microbes, which is limited to the diversity and composition

Methods

Results

Discussion

Conclusion