Elevated Atmospheric CO2 and Nitrogen Fertilization Affect the Abundance and Community Structure of Rice Root-Associated Nitrogen-Fixing Bacteria
Autor: | Jumei Liu, Jingjing Han, Chunwu Zhu, Weiwei Cao, Ying Luo, Meng Zhang, Shaohua Zhang, Zhongjun Jia, Ruihong Yu, Ji Zhao, Zhihua Bao |
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Rok vydání: | 2021 |
Předmět: |
Microbiology (medical)
0303 health sciences Rhizosphere Rhizobiaceae biology 030306 microbiology food and beverages nitrogen fertilization biology.organism_classification Microbiology QR1-502 Rhizobiales elevated atmospheric CO2 03 medical and health sciences Horticulture rice paddy growth stages Methylocystaceae Nitrogen fixation Rhizobium Diazotroph plant-associated nitrogen-fixing bacteria Relative species abundance 030304 developmental biology |
Zdroj: | Frontiers in Microbiology, Vol 12 (2021) |
ISSN: | 1664-302X |
Popis: | Elevated atmospheric CO2 (eCO2) results in plant growth and N limitation, yet how root-associated nitrogen-fixing bacterial communities respond to increasing atmospheric CO2 and nitrogen fertilization (eN) during the growth stages of rice is unclear. Using the nifH gene as a molecular marker, we studied the combined effect of eCO2 and eN on the diazotrophic community and abundance at two growth stages in rice (tillering, TI and heading, HI). Quantitative polymerase chain reaction (qPCR) showed that eN had no obvious effect on nifH abundance in rice roots under either ambient CO2 (aCO2) or eCO2 treatment at the TI stage; in contrast, at the HI, nifH copy numbers were increased under eCO2 and decreased under aCO2. For rhizosphere soils, eN significantly reduced the abundance of nifH under both aCO2 and eCO2 treatment at the HI stage. Elevated CO2 significantly increased the nifH abundance in rice roots and rhizosphere soils with nitrogen fertilization, but had no obvious effect without N addition at the HI stage. There was a significant interaction [CO2 × N fertilization] effect on nifH abundance in root zone at the HI stage. In addition, the nifH copy numbers in rice roots were significantly higher at the HI stage than at the TI stage. Sequencing analysis indicated that the root-associated diazotrophic community structure tended to cluster according to the nitrogen fertilization treatment and that Rhizobiales were the dominant diazotrophs in all root samples at the HI stage. Additionally, nitrogen fertilization significantly increased the relative abundance of Methylosinus (Methylocystaceae) under eCO2 treatment, but significantly decreased the relative abundance of Rhizobium (Rhizobiaceae) under aCO2 treatment. Overall, the combined effect of eN and eCO2 stimulates root-associated diazotrophic methane-oxidizing bacteria while inhibits heterotrophic diazotrophs. |
Databáze: | OpenAIRE |
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