nifH Gene Sequencing Reveals the Effects of Successive Monoculture on the Soil Diazotrophic Microbial Community in Casuarina equisetifolia Plantations

Abstract

The growth and productivity of Casuarina equisetifolia is negatively impacted by planting sickness under long-term monoculture regimes. In this study, Illumina MiSeq sequencing targeting nifH genes was used to assess variations in the rhizospheric soil diazotrophic community under long-term monoculture rotations. Principal component analysis and unweighted pair-group method with arithmetic means (UPGMA) clustering demonstrated distinct differences in diazotrophic community structure between uncultivated soil (CK), the first rotation plantation (FCP), the second rotation plantation (SCP), and the third rotation plantation (TCP). Taxonomic analysis showed that the phyla Proteobacteria increased while Verrucomicrobia decreased under the consecutive monoculture (SCP and TCP). The relative abundance of Paraburkholderia, Rhodopseudomonas, Bradyrhizobium, Geobacter, Pseudodesulfovibrio, and Frankia increased significantly while Burkholderia, Rubrivivax, and Chlorobaculum declined significantly at the genus level under consecutive monoculture (SCP and TCP). Redundancy analysis (RDA) showed that Burkholderia, Rubrivivax, and Chlorobaculum were positively correlated with total nitrogen and available nitrogen. In conclusion, continuous C. equisetifolia monoculture could change the structure of diazotrophic microbes in the rhizosphere, resulting in the imbalance of the diazotrophic bacteria population, which might be a crucial factor related to replanting disease in this cultivated tree species.

Depth-dependent influence of biochar application on the abundance and community structure of diazotrophic under sugarcane growth

“…This process serves as a major source of N, accounting for about 97% into the environment [25]. Recently, a molecular marker of nifH gene family which encodes for the nitrogenase reductase subunit has been used to analyze diazotrophic community structures [25,26]. N2 fixer is sensitive to soil amendment practices.…”

The diversity and structure of diazotrophic communities in the rhizosphere of coastal saline plants is mainly affected by soil physicochemical factors but not host plant species

“…They were also found in the rhizospheric soils of plants grown on Ebinur Lake Wetlands, but not in the paddy fields (Davis et al, 2011;Wang et al, 2020;Zhang et al, 2021). In coastal alkaline soil, Ectothiorhodospira attached to anoxygenic purple sulfur bacteria and played a role in the process of N fixation (Tourova et al, 2014;Zhou et al, 2021). We observed that the community structure of diazotrophic microbes in the tested rhizospheric soil samples were significantly affected by the types of halophytes, and as indicated by the high throughput sequencing analysis, Ectothiorhodospira was significantly different in the diazotrophic microbial community of halophyte rhizosphere (Table 2; Figures 5A-C).…”

Effects of continuous monoculture on rhizosphere soil nutrients, growth, physiological characteristics, hormone metabolome of Casuarina equisetifolia and their interaction analysis

“…These studies have shown that there was an increase in the number of pathogenic microorganisms in rhizosphere soil, and a concurrent decrease in the number of probiotic bacteria. Furthermore, continuous planting results in a reduction in the number of microorganisms involved in the nutrient cycle of C. equisetifolia in rhizosphere soil, a decrease in the expression levels of relevant genes, and a decline in soil available nutrients, ultimately leading to reduced nutrient absorption and accumulation in C. equisetifolia [ [9] , [10] , [11] ].…”