Effect of soil management systems on the rhizosphere bacterial community structure of tobacco: Continuous cropping vs. paddy-upland rotation

Abstract

Rhizosphere bacteria play important role in soil nutrient cycling and plant growth, and their richness and diversity are influenced by soil management systems. However, the specific changes in tobacco rhizosphere bacterial community structure in continuous and tobacco-rice rotation cropping systems remain uninvestigated. In this study, soil properties and the composition of the rhizosphere bacterial community in tobacco monocropping and tobacco-rice rotation cropping systems were analyzed. Moreover, the comparison of rhizosphere bacterial community structure between tobacco continuous and tobacco-rice rotation cropping systems was performed via high-throughput sequencing. The changes in the composition of the rhizosphere bacterial community were investigated at different tobacco growth stages. The results showed that continuous tobacco cropping increased the soil soluble organic carbon (SOC), total nitrogen (TN), and the content of other nutrients (e.g., available phosphorus and available potassium) compared to tobacco-rice rotation cropping. However, monocropping decreased bacterial alpha-diversity and altered the community composition when compared to the rotation cropping system. At the phylum level, the relative abundance of Proteobacteria, Gemmatimonadetes, and Bacteroidetes increased in the continuous cropping soil, while that of Acidobacteria, Firmicutes, and Actinobacteria decreased. At the genera level, the average abundance of the dominant genus Bacillus varied from 12.96% in continuous cropping libraries to 6.33% in the rotation cropping libraries (p < 0.05). Additionally, several other taxa, such as o_Acidobacteriales and Candidatus_Solibacter decreased from 7.63 to 6.62% (p < 0.05) and 4.52 to 2.91% (p < 0.05), respectively. However, the relative abundance of f_Gemmatimonadaceae and c_Subgroup_6 showed an increase of 1.46% (p < 0.05) and 1.63% (p < 0.05) in the tobacco-rice rotation cropping system, respectively. The results of NMDS indicated that the rhizobacteria community structure differed in the two cropping systems. In tobacco, the rhizosphere bacterial community structure showed no significant changes in the prosperous long-term stage and topping stage, but the composition changed significantly in the mature stage.

The composition and diversity of soil microbial community were changed by introducing Phallus impudicus into a Gastrodia elata Bl.-based soil

“…S2). The response of Bacillus in our study are in line with previous ndings in which the relative abundance of genus Bacillus was signi cantly decreased in tobacco-rice rotation cropping system [33]. As far as we know, elements such as potassium, zinc, magnesium, and calcium are easily accessible for soil microorganisms and are prone to change the activity and composition of the microbial community [34].…”

Root exudates and rhizosphere microbiota in responding to long-term continuous cropping of tobacco

“…Rhizosphere microbial community respond to these plantderived metabolites, which in turn feedback on the soil and plant properties 25,38 . Continuous cropping is well known to alter the soil microbial community 5,20,42 , which was also found in our study (Figs. 3 and 4).…”

The succession of rhizosphere microbial community in the continuous cropping soil of tobacco

“…The AP content was relatively low compared to previous studies (10.30 mg/kg-93.90 mg/kg), with only 4.46 mg/kg to 15.58 mg/kg. The AP content was also relatively low compared to previous studies (15.61 mg/kg-98.10 mg/kg), with only 5.05 mg/kg to 15.12 mg/kg (Wang et al, 2020;Wang et al, 2022b;Wang et al, 2022c). The corresponding properties of the control sample CC1Y were basically at the lowest level.…”