Two Distinct Soil Disinfestations Differently Modify the Bacterial Communities in a Tomato Field

Masaru Nakayasu,Shinichi Yamazaki,Yuichi Aoki,Haruhiko Washida,Kazufumi Yazaki,Kyoko Ikeda,Akifumi Sugiyama

doi:10.3390/agronomy11071375

Masaru Nakayasu, Shinichi Yamazaki + Show 5 more

Open Access

https://doi.org/10.3390/agronomy11071375

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Abstract

Reductive soil disinfestation (RSD) and soil solarization (SS) were evaluated based on environmental factors, microbiome, and suppression of Fusarium oxysporum in a tomato field soil. Soil environmental factors (moisture content, electric conductivity, pH, and redox potential (RP)) were measured during soil disinfestations. All factors were more strongly influenced by RSD than SS. 16S rRNA amplicon sequencing of RSD- and SS-treated soils was performed. The bacterial communities were taxonomically and functionally distinct depending on treatment methods and periods and significantly correlated with pH and RP. Fifty-four pathways predicted by PICRUSt2 (third level in MetaCyc hierarchy) were significantly different between RSD and SS. Quantitative polymerase chain reaction demonstrated that both treatments equally suppressed F. oxysporum. The growth and yield of tomato cultivated after treatments were similar between RSD and SS. RSD and SS shaped different soil bacterial communities, although the effects on pathogen suppression and tomato plant growth were comparable between treatments. The existence of pathogen-suppressive microbes, other than Clostridia previously reported to have an effect, was suggested. Comparison between RSD and SS provides new aspects of unknown disinfestation patterns and the usefulness of SS as an alternative to RSD.

Highlights

IntroductionIncreasing food production is one of the most important challenges to meet the global population growth of the 21st century
The Mantel test was used to assess the relationships between soil bacterial communities and environmental factors. It showed that soil redox potential (RP) and pH were significantly correlated with the bacterial communities (p < 0.05; Figure 3). These results suggested that the difference of changes in bacterial communities depends on the soil disinfestation methods and that fluctuation of environmental factors affects the communities
Fusarium wilt is a major soil-borne tomato disease caused by FOL [52] and is difficult to prevent without pesticides

Summary

Introduction

Increasing food production is one of the most important challenges to meet the global population growth of the 21st century. Chemical fertilizers and synthetic pesticides have been used for stable crop growth, pest control, and yield increase worldwide [1]. The management system limiting chemical fertilizers and synthetic pesticides, is a promising solution for these negative impacts. Recent studies propose that organic farming can provide adequate food to the world population in 2050 if consumption of food waste and animal products is reduced [9,10] and that a complete shift to organic farming would be difficult because of global nitrogen deficiency [11]. As soilborne diseases cause severe damage in crops, the appropriate disease management is important, especially in organic farming in which the use of chemical pesticides is restricted. The establishment of the organic farming method is required for its prevalence

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