<i>Epichloë</i> Endophyte Alters Bacterial Nitrogen-Cycling Gene Abundance in the Rhizosphere Soil of Perennial Ryegrass
Perennial ryegrass (<i data-eusoft-scrollable-element="1">Lolium perenne</i>), an important forage and turfgrass species, can establish a mutualistic symbiosis with the fungal endophyte <i data-eusoft-scrollable-element="1">Epichloë festucae</i> var. <i...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-07-01
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| Series: | Biology |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2079-7737/14/7/879 |
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| Summary: | Perennial ryegrass (<i data-eusoft-scrollable-element="1">Lolium perenne</i>), an important forage and turfgrass species, can establish a mutualistic symbiosis with the fungal endophyte <i data-eusoft-scrollable-element="1">Epichloë festucae</i> var. <i data-eusoft-scrollable-element="1">lolii.</i> Although the physiological and ecological impacts of endophyte infection on ryegrass have been extensively investigated, the response of the soil microbial community and nitrogen-cycling gene to this relationship has received much less attention. The present study emphasized abundance and diversity variation in the AOB-<i data-eusoft-scrollable-element="1">amoA</i>, <i data-eusoft-scrollable-element="1">nirK</i> and <i data-eusoft-scrollable-element="1">nosZ</i> functional genes in the rhizosphere soil of the endophyte–ryegrass symbiosis following litter addition. We sampled four times: at T<sub data-eusoft-scrollable-element="1">0</sub> (prior to first litter addition), T<sub data-eusoft-scrollable-element="1">1</sub> (post 120 d of 1st litter addition), T<sub data-eusoft-scrollable-element="1">2</sub> (post 120 d of 2nd litter addition) and T<sub data-eusoft-scrollable-element="1">3</sub> (post 120 d of 3rd litter addition) times. Real-time fluorescence quantitative PCR (qPCR) and PCR amplification and sequencing were used to characterize the abundance and diversity of the AOB-<i data-eusoft-scrollable-element="1">amoA</i>, <i data-eusoft-scrollable-element="1">nirK</i> and <i data-eusoft-scrollable-element="1">nosZ</i> genes in rhizosphere soils of endophyte-infected (E+) plants and endophyte-free (E−) plants. A significant enhancement of total Phosphorus (P), Soil Organic Carbon (SOC), Ammonium ion (NH<sub data-eusoft-scrollable-element="1">4</sub><sup data-eusoft-scrollable-element="1">+</sup>) and Nitrate ion (NO<sub data-eusoft-scrollable-element="1">3</sub><sup data-eusoft-scrollable-element="1">−</sup>) contents in the rhizosphere soil was recorded in endophyte-infected plants at different sampling times compared to endophyte-free plants (<i data-eusoft-scrollable-element="1">p</i> ≤ 0.05). The absolute abundance of the AOB-<i data-eusoft-scrollable-element="1">amoA</i> gene at T<sub data-eusoft-scrollable-element="1">0</sub> and T<sub data-eusoft-scrollable-element="1">1</sub> times was higher, as was the absolute abundance of the <i data-eusoft-scrollable-element="1">nosZ</i> gene at T<sub data-eusoft-scrollable-element="1">0</sub>, T<sub data-eusoft-scrollable-element="1">1</sub> and T<sub data-eusoft-scrollable-element="1">3</sub> times in the E+ plant rhizophere soils relative to E− plant rhizosphere soils. A significant change in relative abundance of the AOB-<i data-eusoft-scrollable-element="1">amoA</i> and <i data-eusoft-scrollable-element="1">nosZ</i> genes in the host rhizophere soils of endophyte-infected plants at T<sub data-eusoft-scrollable-element="1">1</sub> and T<sub data-eusoft-scrollable-element="1">3</sub> times was observed. The experiment failed to show any significant alteration in abundance and diversity of the <i data-eusoft-scrollable-element="1">nirK</i> gene, and diversity of the AOB-<i data-eusoft-scrollable-element="1">amoA</i> and <i data-eusoft-scrollable-element="1">nosZ</i> genes. Analysis of the abundance and diversity of the <i data-eusoft-scrollable-element="1">nirK</i> gene indicated that changes in soil properties accounted for approximately 70.38% of the variation along the first axis and 16.69% along the second axis, and soil NH<sub data-eusoft-scrollable-element="1">4</sub><sup data-eusoft-scrollable-element="1">+</sup> (<i data-eusoft-scrollable-element="1">p</i> = 0.002, 50.4%) and soil C/P ratio (<i data-eusoft-scrollable-element="1">p</i> = 0.012, 15.8%) had a strong effect. The changes in community abundance and diversity of the AOB-<i data-eusoft-scrollable-element="1">amoA</i> and <i data-eusoft-scrollable-element="1">nosZ</i> genes were mainly related to soil pH, N/P ratio and NH<sub data-eusoft-scrollable-element="1">4</sub><sup data-eusoft-scrollable-element="1">+</sup> content. The results demonstrate that the existence of tripartite interactions among the foliar endophyte <i data-eusoft-scrollable-element="1">E</i>. <i data-eusoft-scrollable-element="1">festucae</i> var. <i data-eusoft-scrollable-element="1">Lolii</i>, <i data-eusoft-scrollable-element="1">L. perenne</i> and soil nitrogen-cycling gene has important implications for reducing soil losses on N. |
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| ISSN: | 2079-7737 |