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Fungal endophyte Phomopsis liquidambari affects nitrogen transformation processes and related microorganisms in the rice rhizosphere.

Yang B, Wang XM, Ma HY, Yang T, Jia Y, Zhou J, Dai CC - Front Microbiol (2015)

Bottom Line: A significant increase in the available nitrate and ammonium contents was found in the rhizosphere soil of endophyte-infected rice under low N conditions.Moreover, P. liquidambari significantly increased the potential nitrification rates, affected the abundance and community structure of AOA, AOB, and diazotrophs under low N conditions in the S1 and S2 stages.Plant-soil feedback mechanisms may be mediated by the rice-endophyte interaction, especially in nutrient-limited soil.

View Article: PubMed Central - PubMed

Affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Nanjing China ; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing China.

ABSTRACT
The endophytic fungus Phomopsis liquidambari performs an important ecosystem service by assisting its host with acquiring soil nitrogen (N), but little is known regarding how this fungus influences soil N nutrient properties and microbial communities. In this study, we investigated the impact of P. liquidambari on N dynamics, the abundance and composition of N cycling genes in rhizosphere soil treated with three levels of N (urea). Ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and diazotrophs were assayed using quantitative real-time polymerase chain reaction and denaturing gradient gel electrophoresis at four rice growing stages (S0: before planting, S1: tillering stage, S2: grain filling stage, and S3: ripening stage). A significant increase in the available nitrate and ammonium contents was found in the rhizosphere soil of endophyte-infected rice under low N conditions. Moreover, P. liquidambari significantly increased the potential nitrification rates, affected the abundance and community structure of AOA, AOB, and diazotrophs under low N conditions in the S1 and S2 stages. The root exudates were determined due to their important role in rhizosphere interactions. P. liquidambari colonization altered the exudation of organic compounds by rice roots and P. liquidambari increased the concentration of soluble saccharides, total free amino acids and organic acids in root exudates. Plant-soil feedback mechanisms may be mediated by the rice-endophyte interaction, especially in nutrient-limited soil.

No MeSH data available.


Abundance of amoA [Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB)] and nifH (diazotroph) genes in the rhizosphere soil at four rice growing stages (S0, unplanted soil; S1, tillering; S2, grainfilling; S3, ripening). The values are the means ± SE from three biological replicates. ** indicates significant differences between E+ and E- plants (**P < 0.01). E+, endophyte infected; E-, endophyte uninfected; LN, low N; MN, medium N; HN, high N.
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Figure 2: Abundance of amoA [Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB)] and nifH (diazotroph) genes in the rhizosphere soil at four rice growing stages (S0, unplanted soil; S1, tillering; S2, grainfilling; S3, ripening). The values are the means ± SE from three biological replicates. ** indicates significant differences between E+ and E- plants (**P < 0.01). E+, endophyte infected; E-, endophyte uninfected; LN, low N; MN, medium N; HN, high N.

Mentions: The abundance of AOA, AOB, and diazotrophs was determined by quantifying the copy numbers of amoA and nifH genes. The copy numbers of the archaeal amoA (AOA) gene in the paddy soil, ranging from 2.1 × 106 to 4.9 × 106 g-1 dry weight of soil, were greater than those of the bacterial amoA (AOB) gene, ranging from 0.9 × 106 to 3.0 × 106 g-1 dry weight of soil, during all growing stages. The copy numbers of the nifH gene ranged from 2.9 × 105 to 7.0 × 105 g-1 dry weight of soil, during all growing stages (Figure 2). Compared with the rhizosphere soil of E- plants, the AOA amoA gene abundances in E+ treatments were 8.2% (P < 0.01) higher under low N conditions at the S1 stage, and there was no apparent difference between the E- and E+ treatments at the other three stages. Similarly, the AOB amoA gene abundances in the E+ treatments were 17.3% (P < 0.01) and 7.0% (P < 0.01) higher than that in E- treatments under low N conditions at the S1 and S2 stages, respectively. The nifH gene abundances in E+ treatments were 9.7% and (P < 0.01) and 6.3% (P < 0.01) higher than that in E- treatments under low and medium N conditions at the S1 stage and 3.3% (P < 0.01) higher than that in E- treatments under low N conditions at the S2 stage.


Fungal endophyte Phomopsis liquidambari affects nitrogen transformation processes and related microorganisms in the rice rhizosphere.

Yang B, Wang XM, Ma HY, Yang T, Jia Y, Zhou J, Dai CC - Front Microbiol (2015)

Abundance of amoA [Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB)] and nifH (diazotroph) genes in the rhizosphere soil at four rice growing stages (S0, unplanted soil; S1, tillering; S2, grainfilling; S3, ripening). The values are the means ± SE from three biological replicates. ** indicates significant differences between E+ and E- plants (**P < 0.01). E+, endophyte infected; E-, endophyte uninfected; LN, low N; MN, medium N; HN, high N.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4585018&req=5

Figure 2: Abundance of amoA [Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB)] and nifH (diazotroph) genes in the rhizosphere soil at four rice growing stages (S0, unplanted soil; S1, tillering; S2, grainfilling; S3, ripening). The values are the means ± SE from three biological replicates. ** indicates significant differences between E+ and E- plants (**P < 0.01). E+, endophyte infected; E-, endophyte uninfected; LN, low N; MN, medium N; HN, high N.
Mentions: The abundance of AOA, AOB, and diazotrophs was determined by quantifying the copy numbers of amoA and nifH genes. The copy numbers of the archaeal amoA (AOA) gene in the paddy soil, ranging from 2.1 × 106 to 4.9 × 106 g-1 dry weight of soil, were greater than those of the bacterial amoA (AOB) gene, ranging from 0.9 × 106 to 3.0 × 106 g-1 dry weight of soil, during all growing stages. The copy numbers of the nifH gene ranged from 2.9 × 105 to 7.0 × 105 g-1 dry weight of soil, during all growing stages (Figure 2). Compared with the rhizosphere soil of E- plants, the AOA amoA gene abundances in E+ treatments were 8.2% (P < 0.01) higher under low N conditions at the S1 stage, and there was no apparent difference between the E- and E+ treatments at the other three stages. Similarly, the AOB amoA gene abundances in the E+ treatments were 17.3% (P < 0.01) and 7.0% (P < 0.01) higher than that in E- treatments under low N conditions at the S1 and S2 stages, respectively. The nifH gene abundances in E+ treatments were 9.7% and (P < 0.01) and 6.3% (P < 0.01) higher than that in E- treatments under low and medium N conditions at the S1 stage and 3.3% (P < 0.01) higher than that in E- treatments under low N conditions at the S2 stage.

Bottom Line: A significant increase in the available nitrate and ammonium contents was found in the rhizosphere soil of endophyte-infected rice under low N conditions.Moreover, P. liquidambari significantly increased the potential nitrification rates, affected the abundance and community structure of AOA, AOB, and diazotrophs under low N conditions in the S1 and S2 stages.Plant-soil feedback mechanisms may be mediated by the rice-endophyte interaction, especially in nutrient-limited soil.

View Article: PubMed Central - PubMed

Affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Nanjing China ; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing China.

ABSTRACT
The endophytic fungus Phomopsis liquidambari performs an important ecosystem service by assisting its host with acquiring soil nitrogen (N), but little is known regarding how this fungus influences soil N nutrient properties and microbial communities. In this study, we investigated the impact of P. liquidambari on N dynamics, the abundance and composition of N cycling genes in rhizosphere soil treated with three levels of N (urea). Ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and diazotrophs were assayed using quantitative real-time polymerase chain reaction and denaturing gradient gel electrophoresis at four rice growing stages (S0: before planting, S1: tillering stage, S2: grain filling stage, and S3: ripening stage). A significant increase in the available nitrate and ammonium contents was found in the rhizosphere soil of endophyte-infected rice under low N conditions. Moreover, P. liquidambari significantly increased the potential nitrification rates, affected the abundance and community structure of AOA, AOB, and diazotrophs under low N conditions in the S1 and S2 stages. The root exudates were determined due to their important role in rhizosphere interactions. P. liquidambari colonization altered the exudation of organic compounds by rice roots and P. liquidambari increased the concentration of soluble saccharides, total free amino acids and organic acids in root exudates. Plant-soil feedback mechanisms may be mediated by the rice-endophyte interaction, especially in nutrient-limited soil.

No MeSH data available.