Variation in Bacterial Community Structure in Rhizosphere and Bulk Soils of Different Halophytes in the Yellow River Delta

Abstract

Soil microorganisms play the important role in driving biogeochemical cycles. However, it is still unclear on soil microbial community characteristics and microbial driving mechanism in rhizosphere and bulk soils of different halophyte species. In this study, we analyzed bacterial communities in the rhizosphere and bulk soils of three typical halophytes in the Yellow River Delta, i.e., Phragmites communis, Suaeda salsa, and Aeluropus sinensis, by high-throughput sequencing. The contents of total carbon, total nitrogen, and available phosphorus in rhizosphere soils of the three halophytes were significantly higher than those in bulk soils, which suggested a nutrient enrichment effect of the rhizosphere. Rhizosphere soil bacterial α-diversity of P. communis was higher than that in bulk soil, whereas bacterial α-diversity in rhizosphere soil of S. salsa and A. sinensis was lower than those in bulk soil. The dominant bacterial phyla were Proteobacteria, Actinobacteria, Chloroflexi, and Bacteroidetes, which accounted for 31, 20.5, 16.3, and 10.3%, respectively. LDA effect size (LEfSe) analysis showed that the bacterial species with significant differences in expression abundance was obviously different in the rhizosphere and bulk soil of three halophytes. The principal component analysis (PCoA) showed that bacterial community composition was greatly different between rhizosphere and bulk soils of P. communis and S. salsa, while no difference in A. sinensis. Changed bacterial community composition was mainly ascribed to salinity in rhizosphere and bulk soils. Additionally, salinity was positively correlated with Bacteroidetes and negatively correlated with Actinobacteria and Acidobacteria. Our study clarified the variation in bacterial community structure between rhizosphere and bulk soils with soil physicochemical properties, which proved a biological reference to indicate the characteristics of saline and alkaline land.

Effects of nitrogen and phosphorus imbalance input on rhizosphere and bulk soil bacterial community of Suaeda salsa in the Yellow River Delta

“…Plant root secretion of mucus, shed cells and tissues, and soluble products of ruptured cells all contribute to the TC and SOM of rhizosphere soil (Zhao et al, 2022). In addition, sugars and amino acids secreted by plant roots increase N availability in the soil (Zhao et al, 2022). In this study, the rhizosphere soil contained higher TN, SOM, and TC content compared to the bulk soil, which is evidence that the plant rhizosphere effect is at work.…”

“…Plant root secretion of mucus, shed cells and tissues, and soluble products of ruptured cells all contribute to the TC and SOM of rhizosphere soil (Zhao et al, 2022). In addition, sugars and amino acids secreted by plant roots increase N availability in the soil (Zhao et al, 2022).…”

“…At the CK and N0P treatment, the AP content showed higher in the rhizosphere than in bulk soil. This may be due to the root secretion in the rhizosphere soil, which promoted the P activation and availability (Zhao et al, 2022). This may be caused by plant uptake of P. The addition of N reduces the availability of soil P (Yang et al, 2015).…”

Associative bacterial diversity of pangolão, a stressresilient tropical grass

“…Out of the 325 isolates, 315 amplified the BOX elements, forming bands from 228 to 1,736 bp, which identified 243 strains (Table 2), 78% of which were isolated at a single time, which indicates high diversity. This high diversity was also observed when plant parts or sampling areas were compared through the diversity indexes (Table 2), while dominance, equability, and high Margalef 's richness indexes confirmed that the strains were equally abundant, which usually indicates greater stability and resistance to environmental stresses (Zhao et al 2022). Considering the overall environments, Araripina had the most isolates and higher Shannon's (5.241), Simpson's (0.99) and Margalef 's (7.502) indexes, followed by Nazaré da Mata and Gravatá.…”

Impacts of salinization caused by sea level rise on the biological processes of coastal soils - A review

“…The consequent increase of evapotraspiration further enhances salt accumulation (with the exception of the very dry season where leaf stomata close and traspiration is reduced), exacerbating the process of soil salinization and increasing especially Na + levels in the soil. Moreover, vegetation cover is reduced in halophytic compared to riparian communities, entailing an increase in soil temperature that further boosts salt accumulation due to evaporation (Liu et al, 2019) and causes changes in bacterial community structure (Zhao et al, 2022). Finally, plants can not avoid the passive accumulation of salt in their tissues: this salt is returned to the soil at the end of the growing season, during leaf/root renewal or plant death, supplying salt-enriched litter to the soil and altering OM decomposition.…”