Figures (6)  Tables (4)

    • Figure 1. 

      (a) Variations of easily-extractable glomalin-related soil protein (EE-GRSP), and (b) total GRSP (T-GRSP) between different varieties of mulberry orchids across two soil layers. (c) Soil fertility index load chart in the rhizosphere soil of different varieties mulberry across two soil layers from Gao County and Ningnan County, Sichuan Province, China. Data (means ± SE, n = 3) followed by different letters (a, b, c, d) indicate significant differences among mulberry varieties within the same soil layer (p < 0.05) and different lowercase (x, y) means significant differences between different soil layers in mulberry fields of the same variety (p < 0.05). FT: FengTian; HY: HongYa; YS: YunSang; CS: ChuanSang; BY: BaiYou; QS: QiangSang.

    • Figure 2. 

      Variations in observed (a) mycelium colonization, (b) arbuscular colonization, and (c) vesicle colonization in different cultivars of mulberry orchards. Data (means ± SE, n = 3) followed by different letters (a, b, c, d) indicate significant differences among mulberry varieties (P < 0.05).

    • Figure 3. 

      (a) Composition of AMF communities in the rhizosphere soil of mulberry from Gao and Ningnan Counties, Sichuan Province. (b) Relative abundances of AMF genus in the rhizosphere soil of mulberry across two soil layers from Gao and Ningnan Counties, Sichuan Province. (c) Numbers of the Virtual taxa species in the rhizosphere soil of six different varieties mulberry. (d) Principal coordinate analysis (PCoA) based on OTUs results showing community dissimilarities between different mulberry varieties.

    • Figure 4. 

      Alpha diversity indices, (a) Chao 1, (b) observed species, (c) Simpson, and (d) Shannon of AMF in the rhizosphere soil of mulberry across two soil layers from Gao and Ningnan counties, Sichuan Province. Data (means ± SE, n = 3) followed by different letters (a, b, c, d) indicate significant differences among mulberry varieties within the same soil layer (p < 0.05) and different lowercase (x, y) means significant differences between different soil layers in mulberry fields of the same variety (p < 0.05).

    • Figure 5. 

      Hellinger transformation-based redundancy analysis (tbRDA) of AMF abundance with (a), (b) soil properties, and (c) variation partitioning.

    • Figure 6. 

      Structural equation model (SEM) showing direct and indirect effects of cultivar and AP, AK, SOC, and T-GRSP on AMF richness and diversity. The solid lines indicate significant effect; dashed lines indicate insignificant effect. The black and red lines indicate direct and indirect effect, respectively. The number on each line indicate path coefficients; and R2 values represent the proportion of variance explained for AMF richness and diversity (n = 36).

    • Varieties Location Taxonomic group
      BaiYou Gao County Morus alba L.
      ChuanSang 98-1 Gao County Morus alba L.
      QiangSang 1 Gao County Morus multicaulis Perr.
      HongYa Ningnan County Morus multicaulis Perr.
      YunSang 1 Ningnan County Morus multicaulis Perr.
      FengTian 5 Ningnan County Morus multicaulis Perr.

      Table 1. 

      Basic information of six mulberry varieties in Sichuan Province, southwest China.

    • Variables Soil depth (cm) Gao County Ningnan County F p
      BaiYou ChuanSang 98-1 QiangSang 1 FengTian 5 HongYa YunSang 1
      pH 0−10 5.3 ± 0.2b, y 5.5 ± 0.1b, x 4.9 ± 0.2b, x 7.2 ± 0.2a, x 7.4 ± 0.2a, x 7.2 ± 0.2a, x 97.60 < 0.001
      10−30 6.3 ± 0.1b, x 5.4 ± 0.2c, x 5.0 ± 0.2c, x 7.4 ± 0.3a, x 6.9 ± 0.2a, x 6.7 ± 0.2a, y 145.16 < 0.001
      SOC (g/kg)
      		0−10 9.7 ± 0.1e, x 8.0 ± 0.6f, x 17.5 ± 0.7b, x 118.7 ± 28.6a, x 10.5 ± 0.1d, x 14.3 ± 0.1c, x 41.95 < 0.001
      10−30 9.3 ± 0.2c, x 7.1 ± 0.2c, y 15.4 ± 0.3b, y 69.6 ± 10.9a, y 7.8 ± 0.3d, y 6.9 ± 0.2d, y 93.88 < 0.001
      AN (mg/kg) 0−10 123.0 ± 3.7a, x 136.0 ± 11.0a, x 115.7 ± 3.0b, x 88.5 ± 5.9d, x 104.2 ± 6.5c, x 84.3 ± 12.5d, x 15.89 < 0.001
      10−30 83.0 ± 4.7b, y 107.5 ± 10.6a, y 63.6 ± 6.1b, y 79.8 ± 11.4b, x 52.5 ± 15.4c, y 38.3 ± 10.3c, y 14.55 < 0.001
      AP (mg/kg) 0−10 62.2 ± 4.5d, x 136.1 ± 14.6c, x 25.9 ± 2.6e, x 170.9 ± 16.4a, x 166.0 ± 8.3c, x 257.8 ± 11.2b, x 227.76 < 0.001
      10−30 32.7 ± 2.0d, y 112.2 ± 2.7b, y 16.7 ± 3.1e, y 95.5 ± 5.3a, y 50.7 ± 1.6c, y 25.9 ± 3.3d, y 785.51 < 0.001
      AK (mg/kg) 0−10 47.7 ± 2.1d, x 37.7 ± 0.6e, x 52.3 ± 1.5d, x 179.7 ± 7.5a, x 102.0 ± 2.0c, x 115.3 ± 2.1b, x 741.98 < 0.001
      10−30 40.0 ± 1.0e, y 34.7 ± 1.5f, y 46.3 ± 1.5d, y 126.5 ± 2.6a, y 82.3 ± 0.6c, y 94.7 ± 2.1b, y 1371.3 < 0.001
      Sucrase (mg/g/h) 0−10 0.41 ± 0.10c, x 0.15 ± 0.16d, x 0.11 ± 0.00d, x 2.55 ± 0.21a, x 1.53 ± 0.30b, x 2.81 ± 0.42a, x 30.94 < 0.001
      10−30 0.10 ± 0.08c, y 0.05 ± 0.00c, y 0.06 ± 0.01c, y 1.58 ± 0.23a, y 1.38 ± 0.06a, x 0.80 ± 0.06b, y 48.96 < 0.001
      Urease (mg/g/h) 0−10 0.05 ± 0.00c, x 0.04 ± 0.00d, x 0.03 ± 0.00d, x 0.14 ± 0.00b, x 0.14 ± 0.00b, x 0.20 ± 0.00a, x 87.63 < 0.001
      10−30 0.04 ± 0.00d, x 0.04 ± 0.00d, x 0.04 ± 0.00d, x 0.12 ± 0.01a, y 0.08 ± 0.01b, y 0.06 ± 0.01c, y 92.78 < 0.001
      Values are the means ± SE, n = 3. Different lowercase letters (a, b, c, d) mean significant differences among mulberry varieties within the same soil layer (p < 0.05) and different lowercase letters (x, y) mean significant differences between different soil layers in mulberry fields of the same variety (p < 0.05).

      Table 2. 

      Variations in soil chemical properties and enzymatic activities within the rhizosphere of different varieties mulberry across two soil layers.

    • Group F model R2 Padj
      QiangSang 1 BaiYou 1.94 0.16 0.045
      ChuanSang 98-1 2.00 0.17 0.075
      HongYa 2.55 0.20 0.015
      YunSang 1 2.31 0.19 0.045
      FengTian 5 2.26 0.18 0.045
      BaiYou ChuanSang 98-1 1.88 0.16 0.18
      HongYa 2.75 0.22 0.03
      YunSang 1 2.44 0.20 0.015
      FengTian 5 2.21 0.18 0.105
      ChuanSang 98-1 HongYa 2.26 0.18 0.195
      YunSang 1 2.10 0.17 0.045
      FengTian 5 2.14 0.18 0.21
      HongYa YunSang 1 1.12 0.10 1
      FengTian 5 1.43 0.13 1
      YunSang 1 FengTian 5 1.62 0.14 0.165

      Table 3. 

      PERMANOVA statistical results of AMF communities among six mulberry varieties.

    • Explaining variable RDA model explained
      By variety and soil R2 = 0.507 By soil R2 = 0.350
      Variance F Pr (> F) Variance F Pr (> F)
      Variety 0.115 1.25 0.006 − − −
      AK 0.019 1.05 0.34 0.037 1.94 0.003
      T-GRSP 0.020 1.09 0.28 0.032 1.67 0.003
      Urease 0.023 1.27 0.07 0.023 1.18 0.147
      AP 0.016 0.85 0.85 0.031 1.63 0.004
      EE-GRSP 0.018 0.95 0.60 0.024 1.24 0.100
      SOC 0.021 1.13 0.22 0.027 1.38 0.023
      pH 0.022 1.19 0.14 0.021 1.08 0.292
      Sucrase 0.020 1.11 0.24 0.020 1.02 0.401
      AN 0.022 1.17 0.14 0.021 1.10 0.233

      Table 4. 

      Monte Carlo permutation tests were used to detect the variance explained by varieties and soil properties.