Abstract
Chloropicrin is widely used to control ginger wilt in China, which have an enormous impact on soil microbial diversity. However, little is known on the possible legacy effects on soil microbial community composition with continuous fumigation over different years. In this report, we used high throughput Illumina sequencing and Biolog ECO microplates to determine the bacterial community and microbial metabolic activity in ginger harvest fields of non-fumigation (NF), chloropicrin-fumigation for 1 year (F_1) and continuous chloropicrin-fumigation for 3 years (F_3). The results showed that microbial richness and diversity in F_3 were the lowest, while the metabolic activity had no significant difference. With the increase of fumigation years, the incidence of bacterial wilt was decreased, the relative abundance of Actinobacteria and Saccharibacteria were gradually increased. Using LEfSe analyses, we found that Saccharibacteria was the most prominent biomarker in F_3. Eight genera associated with antibiotic production in F_3 were screened out, of which seven belonged to Actinobacteria, and one belonged to Bacteroidetes. The study indicated that with the increase of fumigation years, soil antibacterial capacity may be increased (possible reason for reduced the incidence of bacterial wilt), and Saccharibacteria played a potential role in evaluating the biological effects of continuous fumigation.
Highlights
Soil fumigants are used extensively to control soil-borne pests including nematodes, pathogens, and weeds, so that increasing the yields of many crops (Mao et al 2013; Wang et al 2014; Ibekwe 2004)
The average read length was 438 bp. These bacterial Operational taxonomic units (OTUs) were assigned to 38 different phyla
The relative abundance of phyla Saccharibacteria and Actinobacteria were increased as the fumigation years increased
Summary
Soil fumigants are used extensively to control soil-borne pests including nematodes, pathogens, and weeds, so that increasing the yields of many crops (Mao et al 2013; Wang et al 2014; Ibekwe 2004). Bacterial wilt on ginger, caused by the soil-borne bacterial pathogen Ralstonia solanacearum, is a major disease responsible for enormous yield losses (Yang et al 2012). Without soil fumigation, it can cause an 80% crop failure in ginger (Li et al 2014). Rhizosphere bacteria are antagonistic to soil-borne pathogens by preventing their infection on hosts (Latz et al 2012). It is possible to bring back the soil suppressive status in a way changing the composition of rhizosphere bacteria (van Agtmaal et al 2015)
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