Effects of Cr stress on bacterial community structure and diversity in rhizosphere soils of Iris pseudacorus

Abstract

Rhizosphere microorganisms play an important role in improving soil microenvironment, which contributes to plant growth under heavy metal stress. However, the effect of chromium (Cr) on plant rhizosphere bacterial community is still unknown. In this paper, sole-cultivated pattern, two-cultivated pattern and three-cultivated pattern, combined with 16S rRNA high-throughput sequencing technology, the effects of Cr stress on bacterial community structure and diversity in rhizosphere soil of Iris Pseudacorus were analyzed. The results showed that under Cr stress, I. Pseudacorus showed good tolerance and enrichment. However, under Cr stress, the Alpha diversity indices (Shannon, Chao and Sobs) of rhizosphere bacterial community decreased by 9.1%, 30.3% and 28.0% on average, respectively. The change of bacterial community was 22.6% due to Cr stress, and the common species of bacterial community decreased by 4.2%. Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes and Gemmatimonadetes accounted for more than 78.2% of the total sequence. With the increase of plant diversity, Bacteroides and Pseudomonas appeared successively, and the abundance of the dominant species increased obviously. Through the symbiotic network diagram, it was found that the synergistic effect between dominant species in two-cultivated pattern was significantly enhanced, and the soil microenvironment was significantly improved. In conclusion, the results of this study will provide a reference for understanding the response of rhizosphere bacterial community to heavy metal Cr and the interaction between wetland plants and rhizosphere bacteria during wetland phytoremediation.

Recruitment and metabolomics between Canna indica and rhizosphere bacteria under Cr stress

“…Previous studies have found that the increase in the abundance of Acidobacteriota can promote the absorption of Cd by plants because organic acids secreted by Acidobacterium can promote the release of Cd from soil colloids (Ganesh et al, 2022). In this study, with the passage of Cr stress time, the abundance of Acidobacteriota decreased to 3.82% in Group Cr21 (Figure 4E), which may be caused by the decrease of Cr content in the rhizosphere with the extension of Cr stress time (Wei et al, 2023c). Rhizosphere microorganisms can induce the production of flavonoid antioxidant substances in plants, thereby enhancing the resilience of plants to oxidative stress (Wang et al, 2022b).…”

“…In addition, during the seedling culture period, Hoagland solution (15 ml) and water (15 ml) were added into the soil culture pot every 15 and 3 days successively. If Cr was added to the stress experiment, the Hoagland nutrient solution was not required (Si et al, 2022;Wei et al, 2023c).…”

A comparative genomics study of the microbiome and freshwater resistome in Southern Pantanal

“…Longterm nitrogen deposition may also decrease the available organic matter of soil microorganisms, reducing microbial activity and diversity. Another study found that the presence of certain pollutants, such as chromium, can also reduce alpha diversity (Wei et al, 2023). Although we do not have data regarding nutrient and contaminant concentrations, bodies of water near farms often have high concentrations of these nutrients and heavy metals due to agricultural practices.…”