Rhizosphere and non-rhizosphere bacterial characteristics analysis of young Taxodium ‘Zhongshanshan 118’ in Huaihe Plain of North Anhui

Abstract

In order to explore the effects of ecological landscaping tree species Taxodium ‘Zhongshanshan 118’ on soil microbial ecosystem in Huaihe Plain of north Anhui Province, the differences in soil nutrients levels, microbial communities structures and their influencing factors between the rhizosphere (R) and non-rhizosphere (NR) were analyzed. The results were as follows: (1) The 4-year-old Taxodium ‘Zhongshanshan 118’ rhizosphere had a low enrichment capacity for macronutrients, resulting in a deficiency of hydrolyzable nitrogen and available phosphorus. The R had similar levels of total nitrogen, and lower levels of total phosphorus, total potassium and available potassium than the NR soil. The R had a strong enrichment ability for microelements (iron, copper, manganese). And the available manganese content in the R was significantly higher than that in the NR. Both the R and the NR soils of Taxodium ‘Zhongshanshan 118’ were alkaline. The R had a slightly lower pH and a higher electrical conductivity than the NR. The R had a certain degree of enrichment for available sodium, available magnesium and available calcium, as well as for organic carbon and organic matter. (2) Based on the Anosim analysis of community structure between groups, the R value was 0.224 (P=0.022), which was significantly greater than 0, indicating significant differences between the bacterial communities of the R and the NR of Taxodium ‘Zhongshanshan 118’. The total number of OTUs in the R and the NR was 5 283. There were 1 307 unique OTUs in R and 1 265 OTUs in NR. (3) The R had a slightly lower bacterial diversity than the NR. The dominant phylum in both the R and the NR were Firmicutes, Proteobacteria, Acidobacteriota, Bacteroidetes, Chloroflexi, Myxococcota, Actinobacteria, and Crenarchaeota. Among them, only Acidobacteriota showed a significant positive correlation with available phosphorus. The R had higher abundances of Firmicutes (17.94%) and Bacteroidetes (5.21%) than the NR (1.84% and 3.90%), respectively. Neither of them had a significant correlation with environmental factors. The R had higher abundances of Clostridia, Bacteroidia and Bacilli than the NR by 14.05%, 1.32% and 2.06%, respectively. (4) The UPGMA clustering analysis showed that R4 was isolated from the other samples. NR4 and NR5 formed a cluster, NR1, NR2 and NR3 clusted with R1, R2, R3 and R5. R4 had lower species diversity and abundance than the other samples, and had an uneven distribution of taxa. In conclusion, despite the weak rhizosphere effect of young Taxodium ‘Zhongshanshan 118’, it was the main factor for the enrichment of Firmicutes and Bacteroidetes in the rhizosphere. And more microelements and a moderate amount of macroelements should be applied in the cultivation process.

Keywords

• taxodium ‘zhongshanshan 118’
• rhizosphere
• non-rhizosphere
• bacterial
• soil nutrients
• high throughput sequencing