Fig 1.
The chemical structure of the repeated unit of salecan.
Table 1.
PCR primers and targeted microorganisms used in this study.
Fig 2.
Changes in soil bacteria community structure.
(a) Bacterial colony-forming units assessed using the culture plating method. All values are the means ± SD (n = 3). (b) Similarity dendrogram of the bacterial banding patterns of soil samples. The scale for 0.44–1.00 was the similarity coefficient among the samples. DGGE fingerprints of 16S rDNA sequences amplified using the primer pair 357fGC/518r from soil-extracted community DNA. Lanes 1, 2 and 3 show the results of soil samples without salecan treatment (C); lanes 4, 5 and 6 show the results of 0.02% salecan-treated samples; and lanes 7, 8 and 9 show the results of 0.2% salecan-treated samples. Seven changed DGGE bands (B1, B2, B3, B4, B5, B6, B7) are marked by arrows. (c) The phylogenetic relationship between the 16S rRNA gene sequences of the soil samples and the related organisms from the GenBank database. The dendrogram was generated using the neighbor-joining method, with 1000 bootstrap resamplings. The scale bar represented 0.02, estimated nucleotide changes per sequence position.
Fig 3.
Changes in the soil fungus community structure.
(a) Fungal colony-forming units assessed using the culture plating method. All values are the means ± SD (n = 3). *P < 0.05 vs 0% group. (b) Similarity dendrogram of the fungal banding patterns of the soil samples. The scale for 0.49–1.00 was the similarity coefficient among the samples. DGGE fingerprints of the 18S rDNA sequences amplified using the primer pair Fung-GC/NS1 from soil-extracted community DNA. Lanes 1, 2 and 3 show the results of soil samples treated without salecan (C); lanes 4, 5 and 6 show the results of 0.02% salecan-treated samples; and lanes 7, 8 and 9 show the results of 0.2% salecan-treated samples. Five changed DGGE bands (F1, F2, F3, F4, F5) are marked by vertical black lines. (c) The phylogenetic relationship between the 18S rRNA gene sequences from the soil samples and related organisms from the GenBank database. The dendrogram was generated using the neighbor-joining method with 1000 bootstrap resamplings. The scale bar represented 0.5, estimated nucleotide changes per sequence position.
Fig 4.
The relative abundances of the two fungal groups in soil samples treated with different concentrations of salecan, as estimated using qPCR assays. The results show DNA from Fusarium oxysporum (a) and Trichoderma spp. (b). All values are the means ± SD (n = 3). **P < 0.01 vs 0% group.
Fig 5.
β-1,3-Glucanase activity in soil samples treated with different amounts of salecan.
The soil β-1,3-glucanase activity was defined as the amount of enzyme required to release 1 mg of glucose per day per gram soil (mg/d/g). All values are the means ± SD (n = 3). *P < 0.05 vs 0% group.