Soil enzyme activities and soil microbial biomass
As shown in Table 2, the new planting treatments, the activities of β-Glucosidase and Aminopeptidase in tissue culture (TCN treatment) were all significantly higher than those of conventional (stem) propagation (CSN treatment) and background (BG treatments). However, the activity of Acid phosphatase was not significantly different between the TCN and CSN treatments. In addition, the ratoon canes, only the activity of Aminopeptidase in TCR treatment was significantly higher than those of CSR and BG treatments. Moreover, the activities of β-Glucosidase and Acid phosphatase in TCR and CSR treatments were all significantly higher than those of the BG treatment, however, they were not significant difference between each other. The results suggested that soil carbon and nitrogen cycles in rhizospheres of sugarcanes could be significantly improved by tissue culture propagation method which compared to conventional propagation method.
Table 2
Soil enzyme activities in rhizospheres of sugarcanes under different propagation methods (nmolg − 1 ·min− 1 ·30°C)).
Planting time | Treatments | β-Glucosidase | Aminopeptidase | Acid phosphatase |
Newly planted | TCN | 0.98 ± 0.02a | 15.54 ± 0.75a | 0.77 ± 0.71a |
CSN | 0.74 ± 0.06b | 10.20 ± 1.35b | 0.84 ± 0.10a |
BG | 0.24 ± 0.08c | 5.34 ± 0.96c | 0.68 ± 0.08b |
Ratoon | TCR | 0.57 ± 0.16a | 11.27 ± 1.26a | 0.53 ± 0.12a |
CSR | 0.52 ± 0.08a | 8.56 ± 0.53b | 0.65 ± 0.11a |
BG | 0.24 ± 0.08b | 5.31 ± 0.96b | 0.68 ± 0.08b |
Notes: All data are presented as mean ± standard deviation. Different letters in the same column indicate significant differences (two-tailed Duncan’s test) between treatments at P < 0.05. TCN: Tissue culture seedlings (Newly planted ); CSN: Conventional(stem) propagation(Newly planted ), TCR: Tissue culture propagation (ratoon cane); CSR: Conventional (stem ) propagation( ratoon cane);BG, background. |
As shown in Table 3, the new planting treatments, although soil microbial biomass carbon (MBC)and soil microbial biomass phosphorus (MBP) in TCN and CSN treatments were not significantly higher between each other, but they all significantly higher than those of BG. Additionally, only soil microbial biomass nitrogen (MBN) in the TCN treatment was significantly higher than those of the CSN treatment. Moreover, the ratoon treatments, soil microbial biomass carbon, nitrogen and phosphorus (MBC, MBN and MBP) in TCR and CSR treatments were all not significantly different between each other.
All above results related to soil enzymes activities, it indicated that soil fertility in rhizospheres of sugarcanes could be significantly improved by tissue culture propagation method which compared to conventional propagation method. Particularly, the improvement effect easily could be found in newly planted with tissue culture seedlings.
Table 3
Soil microbial biomass carbon (MBC), nitrogen (MBN) and phosphorus (MBP) in rhizospheres of sugarcanes under different propagation methods (mg.kg− 1).
Planting time | Treatments | MBC | MBN | MBP |
Newly planted | TCN | 323.54 ± 31.20a | 19.52 ± 0.65a | 37.78 ± 18.32a |
CSN | 346.69 ± 21.79a | 15.33 ± 1.04b | 41.60 ± 11.49a |
BG | 155.16 ± 19.61b | 8.98 ± 1.80b | 26.03 ± 1.19b |
Ratoon | TCR | 153.71 ± 25.90a | 17.72 ± 1.23a | 38.78 ± 17.07a |
CSR | 138.58 ± 16.75a | 18.22 ± 2.63a | 41.33 ± 5.54a |
BG | 155.16 ± 19.61a | 8.98 ± 1.80b | 26.03 ± 1.19b |
Notes: All data are presented as mean ± standard deviation. Different letters in the same column indicate significant differences (two-tailed Duncan’s test) between treatments at P < 0.05. TCN: Tissue culture seedlings (Newly planted); CSN: Conventional(stem) propagation (Newly planted ), TCR: Tissue culture propagation(ratoon cane); CSR: Conventional (stem) propagation (ratoon cane);BG, background. |
Soil bacterial community structure in rhizospheres of sugarcanes under different propagation methods
In newly planted treatments, the Shannon indexes of soil bacteria in rhizospheres of sugarcanes were not significantly different between TCN and CSN. However, the Ace and Chao indices of soil bacteria in TCN treatment were significantly higher than those of the CSN and BG treatments(Fig. 1.a, b, c). Moreover, significant differences of soil bacterial compositions in rhizospheres of sugarcanes Between TCN and CSN treatments were also detected. (Fig. 1.d) Meanwhile, soil bacteria in rhizospheres of sugarcanes growing from newly planted tissue culture propagation (TCN) and conventional propagation (CSN) also clustered separately (Fig. 1. e). Moreover, the numbers of soil bacteria at OTU level in TCN, CSN and BG treatments were 3244, 2931 and 2953, respectively; also, the numbers of special bacteria at OTU level in TCN, CSN and BG treatments were 501, 337 and 351, respectively. (Fig. 1. f)
All above results suggested that soil bacterial compositions in rhizospheres of newly planted sugarcanes growing from different propagation methods were significant differences.
Similarly, in ratoon cane treatments, not only the Shannon indexes of soil bacteria in rhizospheres of sugarcanes growing from TCP treatments were also significantly higher than those of CSR treatments, but also their compositions under TCR and CSR and BG treatments were clustered separately (Fig. 1. g,h,i,j,k). Moreover, at the OTU level, the numbers of soil bacteria in TCR, CSR and BG treatments were 3424, 2852 and 2953, respectively; Also, the unique numbers of soil bacteria in rhizospheres of sugarcanes in TCR, CSR and BG were 486, 359 and 318, respectively (Fig. 1. l). It indicated that soil bacterial compositions in rhizospheres of ratoon canes growing from different propagation methods were also significant differences.
All above results suggested that soil bacterial community structure in rhizospheres of sugarcanes was significantly altered by different propagation methods. In comparison with conventional propagation, the abundance and numbers of soil bacteria in rhizospheres of sugarcanes could be significantly increased by tissue culture propagation method.
Additionally, at the phylum level, Actinobacteriota (30.32%), Proteobacteria (27.78%), Chloroflexi (15.93%), Acidobacteriota (10.68%), Bacteroidota (3.12%), Myxococcota (2.08%), Patescibacteria (1.95%), Gemmatimonadota (1.44%), Verrucomicrobiota (1.13%) and others (5.57%) were the soil dominant bacterial phyla (relative abundance were greater than 1%)in the newly planted tissue culture propagation (TCN) treatment; By contrast, Proteobacteria (29.16%), Actinobacteriota (25.88%), Chloroflexi (18.47%), Acidobacteriota (11.40%), Bacteroidota (2.48%), Patescibacteria (2.28%), WPS-2 (2.13%), Myxococcota (1.58%), Firmicutes (1.45%) and others (5.17%) were the soil dominant bacterial phyla in the newly planted conventional propagation (CSN) treatment. ༈ Fig. 2.a༉
Meanwhile, Actinobacteriota (29.88%), Proteobacteria (24.33%), Chloroflexi (18.54%), Acidobacteriota (11.21%), Bacteroidota (2.41%), Myxococcota (1.65%), Patescibacteria (1.48%), Gemmatimonadota (1.48%), Firmicutes (1.28%), WPS-2 (1.28%), Planctomycetota: (1. 15%), Verrucomicrobiota (1. 13%), Cyanobacteria (1. 12%), Nitrospirota (1 .03%), and others (5.57%) were the soil dominant bacterial phyla in the ratoon tissue culture propagation (TCR) treatment; In contrast, Proteobacteria (32.30%), Actinobacteriota (34.23%), Chloroflexi (9.77%), Acidobacteriota (10.22%), Bacteroidota (3.09%), Patescibacteria (1.92%), Myxococcota (1.67%), and Verrucomicrobiota (1. 18%), Planctomycetota (1.04%), Gemmatimonadota (1.00%) and others (5.58%) were the soil dominant bacterial phyla in the ratoon conventional propagation (CSR) treatment; Moreover, Actinobacteriota (31.47%), Proteobacteria(21.87%), Chloroflexi(20.08%), Acidobacteriota (12.21%) Gemmatimonadota (2.76%), Myxococcota (1.86%), Firmicutes (1.59%), and Nitrospirota (1 .22%), Cyanobacteria (1.02%) and others (5.92%) were the soil dominant bacterial phyla in the background (BG) treatment.(Fig. 2.c)
At the genus level, the numbers of soil dominant bacterial genera (relative abundance were greater than 1%)obtained from the newly planted tissue culture propagation (TCN), conventional propagation (CSN) and BG treatments were 17, 17 and 22, respectively; Among them, norank_f_norank_o_Gaiellales, norank_ f_norank_o_norank_c_AD3, Bradyrhizobium, norank_f_norank_o_norank_c_TK10, Sphingomonas, Conexibacter, norank_f_norank_0_Acidobacteriales and Streptomyces norank_o_norank_C_TK10, Sphingomonas, Conexibacter, norank_ f_norank_0_Acidobacteriales and Streptomyces were the soil common dominant bacterial genera in the TCN, CSN and BG treatments. In comparison with conventional propagation (CSN), the proportions of norank _f_norank_o_Gaiellales, norank_ f_norank_ o_norank_c_ AD3, Bradyrhizobium, Sphingomonas, Streptomyces, Arthrobacter and Sinomonas increased;norank_f_norank_o_norank_c_TK10, Burkholderia-Caballeronia-Pareaburkholderia and Conexibacter declined in newly planted tissue culture propagation (TCN). Meanwhile, unclassifed_f_Intrasporangiaceae was the specific soil dominant bacterial genus in rhizospheres of sugarcanes under the TCN treatment. By contrast, unclassified_ f_ Ktedonobacteraceae, norank_ f_ norank_ o_ norank_ c_ norank_p_WPS-2 and norank_ Micropepsaceae were the unique soil dominant bacterial genera in rhizospheres of sugarcanes under the CSN treatment༈Fig. 2.b༉.
Furthermore, the numbers of soil dominant bacterial genera obtained from ratoon tissue culture propagation (TCR), conventional propagation (CSR) and background (BG) treatments were 26, 19 and 22, respectively. Among them, norank_f_norank_o_Gaiellales, norank_ f_norank_o_norank_c_AD3, Bradyrhizobium, norank_f_ norank_o_norank_c_TK10, Sphingomonas, Conexibacter, Bryobacter, norank_f_Xanthobacteraceae, unclassified_f_Micrococcaceae, Streptomyces, Candidatus_ Solibacter, Candidatus_Solibacter and Acidothermus were the soil common dominant bacterial genera in the TCR, CSR and BG treatments. In comparison with ratoon conventional propagation (CSR), the proportions of norank_ f_norank_ o_norank_c_AD3, norank_f_norank_o_norank_c_TK10, Conexibacter and norank_ f_Xanthobacteraceae incrased, but the proportions of norank_f_norank_o_Gaiellales, Bradyrhizobium, Burkholderia-Caballeronia-Pareaburkholderia, Mycobacterium and Acidothermus declined in rhizospheres of sugarcanes under ratoon tissue culture propagation (TCR). Moreover, unclassified_ f_Ktedonobacteraceae、norank_ f_ norank_ o_ norank_c_norank_p_WPS-2 and norank_ Micropepsaceae were the specific soil dominant bacterial genera in rhizospheres of sugarcane under to the TCR treatment. By contrast, Arthrobacter, unclassifed_f_ Intrasporangiaceae, Reyranella and Chujaibacter were the unique soil dominant bacterial genera in rhizospheres of sugarcane under the CSR treatment(Fig. 2.d).
Meanwhile, at the phylum level, Bacteroidota significantly enriched and at the genus level, unclassified_f__Micrococcaceae, Bradyrhizobium, Arthrobacter, norank_f__Roseiflexaceae, unclassified_f__Intrasporangiaceae significantly enriched in the tissue culture propagation (TCN) treatment. By contrast, at the genus level, Burkholderia-Caballeronia-Paraburkholderia, Acidothermus, Conexibacter, norank_f__Micropepsaceae and Rhodanobacter significantly enriched in the conventional propagation (CSN) treatment. Moreover, at the phylum level, Gemmatimonadota and at the genus level, norank_f__norank_o__Gaiellales, Gaiella, norank_f_Gemmatimonadaceae, Bryobacter, unclassified_f__Micromonosporaceae, norank_f__norank_o__Elsterales significantly enriched in the BG treatment.( Fig. 2.e)
Furthermore, at phylum level, in comparison with TCR treatment, only Bacteroidota and Patescibacteria could be detected enriching in the CSR treatment, By contrast, Gemmatimonadota also significantly enriched in the BG treatment; At genus level, only Sinomonas significantly enriched in the TCR treatment; In contrast, Burkholderia-Caballeronia-Paraburkholderia, norank_f__ Micropepsaceae, Actinospica, unclassified_f__Intrasporangiaceae, Mucilaginibacter, Acidipila, Reyranella, Catenulispora and norank_f__LWQ8 significantly enriched in the CSR treatment; meanwhile, Gaiella, norank_f__Micromonosporaceae, norank_f__Roseiflexaceae and norank_f__Gemmatimonadaceae significantly enriched in the BG treatment (Fig. 2.f).
Soil fungal community structure in rhizospheres of sugarcanes under different propagation methods
The Shannon indices of soil fungi in rhizospheres of sugarcanes under newly planted tissue culture propagation (TCN) treatments were significantly higher than those of the conventional propagation (CSN) and background (BG). However, the Ace and Chao indices of soil fungi, there was no significant difference between the TCN and CSN treatments (Fig. 3. a, b, c). Additionally, significant differences of soil fungal composition in rhizospheres of sugarcanes were found between newly planted tissue culture propagation (TCN) and conventional propagation (CSN). (Fig. 3. d,) Meanwhile, soil fungi in rhizospheres of sugarcanes growing from newly planted tissue culture propagation (TCN) and conventional propagation (CSN) also clustered separately. It indicated that soil fungal community structure in rhizospheres of sugarcanes between TCN and CSN were significant differences (Fig. 3. e); Moreover, the numbers of soil fungi at the OTU level obtained from the TCN, CSN and BG treatments were 1502, 1324 and 1190, respectively; Furthermore, the numbers of unique soil fungi in TCN, CSN and BG treatments were 528, 325 and 278, respectively. (Fig. 3.f)
Similarly, in ratoon cane treatments, the Shannon indices of soil fungi in rhizospheres of sugarcane in TCR treatment were significantly higher than those of CSR treatment. And the Ace and Chao indices of soil fungi, they were also significantly higher in TCR and CSR treatments than those of BG treatments, but there was no significant difference between TCR and CSR treatments (Fig. 3. g,h,i). Also, soil fungal compositions in rhizospheres of sugarcanes under TCR, CSR and BG clustered separately. It suggested that soil fungal community structure between TCR and CSR were significant differences (Fig. 3. J,k). Furthermore, the numbers of soil fungi obtained from the TCR, CSR and BG treatments at OTU level were 1502, 1324 and 1190, respectively. Meanwhile, the special numbers of soil fungi in rhizospheres of sugarcanes at OTU level under TCR, CSR and BG were 528, 325 and 278, respectively (Fig. 3.l).
All above results indicated that soil fungal community structure in rhizospheres of sugarcanes was also significantly altered by different propagation methods. In comparison with conventional propagation, tissue culture propagation could significantly increase the diversity of soil fungi in rhizospheres of sugarcanes.
At the phylum level, Ascomycota (77. 36%), Basidiomycota (16 34%), unlasifed_K_ Fungi (3.24%), Mortierellomycota (1.91%) and others (1.14%) were the soil dominant fungal phyla in rhizospheres of sugarcanes under the TCN treatment; In contrast, Ascomycota (70.83%), Basidiomycota (21.37%), unlasifed_k_Fungi (5.56%), Mortierellomycota (1.18%) and others (1.06%) were the soil dominant fungal phyla in rhizospheres of sugarcanes under the CSN treatment; And Ascomycota ( 55.54%), Basidiomycota (38.39%), unlasifed_k_ Fungi (3.54%) and Mortierellomycota (1.66%) were the soil dominant fungal phyla in the BG treatment. (Fig. 4.a)
In addition, Ascomycota (55.81%), unlasifed_k_ Fungi (26.73%), Basidiomycota (15.11%) and Mortierellomycota (1.84%) were the soil dominant fungal phyla in the tissue culture propagation (TCR) method with ratoon canes; By contrast, Ascomycota (55.81%), unlasifed_k_Fungi (26.73%), Basidiomycota (15.11%) and Mortierellomycota (1.84%) were the soil dominant fungal phyla in the conventional propagation (CSR)method with ratoon canes; Meanwhile, Ascomycota (55.54%), Basidiomycota (38.39%), unlasifed_k_Fungi (3.54%) and Mortierellomycota (1.66%) were the soil dominant fungal phyla in the BG treatment( Fig. 4.b).
At the genus level, the numbers of soil dominant fungal genera obtained for the newly planted tissue culture propagation (TCN), conventional propagation (CSN) and BG treatments were 28, 20 and 22, respectively. Among them, unclassified_ k_ Fungi, Saitozyma, Trichoderma, Talaromyces, Chaetomium, unclassified_c_ Sordariomycetes, Fusarium, Peinicllium, unclasifed_p_Ascomycota, Mortierella, Trichocladium and Coniosporium were the common soil dominant fungal genera in rhizospheres under the TCN, CSN and BG treatments. Additionally, Sarocladium, unclassified_o_Pleosporales, Sistotrema, Exophiala, Rhizoctonia, unclassified_o_Eurotiales, Trechispora, Poaceascoma, Psathyrella, Aspergillus, Wongia, Cercophora and Pseudorobillarda were the special soil dominant fungal genera in rhizospheres of sugarcanes under the TCN treatment; By contrast, Gonytrichum, unclassified_o_Chaetothyriales, Papiliotrema, Cercophora, Ramophialophora, Phialocephala were the unique soil dominant fungal genera in rhizospheres of sugarcanes under the CSN treatment; Meanwhile, Ceratobasidium, Micropsalliota were the specific soil dominant fungal genera in BG treatment ( Fig. 4.c).
Moreover, the numbers of soil dominant fungal genera in rhizospheres of sugarcanes obtained from the TCR, CSR and BG treatments were 19, 20 and 22, respectively. Among them, unclassified_ k_ Fungi, Saitozyma, Trichoderma, Talaromyces, Chaetomium, unclassified_ c_ Sordariomycetes, Fusarium, Peinicllium, unclasifed_p_Ascomycota, Trichocladium and Coniosporium were the common soil dominant fungal genera in rhizospheres of sugarcanes under the TCR, CSR and BG treatments; And unclassified_o_ Pleosporales, unclassified_f_Agaricaceae, Sistotrema and unclassified _ c_ Agaricomycetes were the specific soil dominant fungal genera in rhizospheres of sugarcanes under the TCR treatments; In contrast, Caopialophora, Chaetosphaeria, Gonytrichum, unclassified_ o__ Trechisporales, Nigrospora, Clonostachys and unclassified_ o__ Chaetothyriales were the unique soil dominant fungal genera in rhizospheres of sugarcanes under the CSR treatment; Ceratobasidium, Micropsalliota were the specific soil dominant fungal genera in the BG treatment (Fig. 4.d).
LEfSe analysis showed that Ascomycota, and Exophiala, Rhizoctonia, Chaetosphaeria, Wongia, Sarocladium, Psathyrella, Aspergillus, Monocillium, Acremonium significantly enriched in rhizospheres of sugarcanes under newly planted tissue culture propagation (TCN) method. By contrast, Talaromyces, Trichoderma, Cladophialophora, unclassified_f__Pezizaceae and unclassified_p__Rozellomycota significantly enriched in rhizospheres of sugarcanes under conventional propagation (CSN) method; Basidiomycota, and Micropsalliota, Fusarium, Pseudallescheria, unclassified_o__Sordariales and Neocosmospora significantly enriched in BG treatment. (Fig. 4.e)
In addition, unclassified_k__Fungi, at phylum level, and Acremonium, unclassified_c__Agaricomycetes, Sarocladium, unclassified_f__Glomeraceae, Paraconiothyrium, Penicillium, Coniophora, at genus level, significantly enriched in rhizospheres of sugarcanes under the TCR treatment; In contrast, Trechispora, Chaetosphaeria, Trichoderma, Talaromyces, unclassified_o__ Trechisporales, Fonsecaea,Zopfiella, Clitopilus, Phialophora, Phallus, Psathyrella, unclassified_o__Eurotiales and Chalara significantly enriched in rhizospheres of sugarcanes under the CSR treatment; Moreover, Chaetomium, Coniosporium, unclassified_o__Chaetothyriales, Lipomyces and Scleroderma significantly enriched in the BG treatment. (Fig. 4.f)
Overall structure of cane root metabolites across samples
To verify the effect of different propagation methods on the expression of cane root metabolites, PCA analysis was performed to show a clear separation between the TCN and SSN treatments (Fig. 5.a), and the TCR and SSR treatments (Fig. 5.d). At seen at the Fig. 5.a and d, the expressions of cane root metabolites, not only at newly planted canes, but also the ratoon canes root metabolites were significantly influenced by different propagation methods.
Outliers, also can be detected and excluded using the OPLS-DA model. The OPLS-DA model showed that significant separations could be found between the TCN and CSN groups (R2X = 0.421, R2Y = 0.999, Q2 = 0.945, Fig. 5. b,c), and the TCR and CSR groups (R2X = 0.505, R2Y = 0.998, Q2 = 0.892, Fig. 5. e,f) .
Using the VIP threshold 2 (P < 0.05), we obtained 146 and 117 metabolic differentials in the newly planted treatment and the ratoon treatment, respectively. In addition, to visualize differences in the metabolome of sugarcane roots between the two propagation methods, we performed a hierarchical cluster analysis (HCA) with heat maps. The results showed that 10 different metabolites clusters were formed between the newly planted and the ratoon treatments. (Fig. 6a). Among them, cluster 4, 5, 7, 8 and 9 up-regulated in the TCN treatment which compared to the CSN. Also, cluster 1, 4, 5, 8 and 9 up-regulated in the TCR treatment which compared to the CSR, too (Fig. 6b). It also suggested that cane root metabolites were also significantly altered by different propagation methods too.
The above metabolites were assigned to the Kyoto Encyclopedia of Genes and Genomes (KEGG) database (kegg_v2021.09.18). Of these, 11 and 13 KEGG secondary pathways were obtained in the newly planted canes (TCN vs CSN)and the ratoon canes༈TCR vs CSR༉, respectively. In newly planted canes ༈TCN vs CSN༉, the most important metabolism was Biosynthesis of other secondary metabolites, followed by Amino acid metabolism, Metabolism of cofactors and vitamins, Metabolism of terpenoids and polyketides and Carbohydrate metabolism (Fig. 7.a,d). By contrast, In ratoon canes༈TCR vs CSR༉, the most important metabolism was also the Biosynthesis of other secondary metabolites, followed by Amino acid metabolism, Lipid metabolism, Nucleotide metabolism and Carbohydrate metabolism.
KEGG topology analysis was also used to determine the biological pathways involved in differentially expressed metabolites in different propagation methods. The results showed that three metabolic pathways effect values were greater than 0.3 in both the newly planted (TCN vs CSN)and ratoon treatments༈TCR vs CSR༉, respectively. Three significantly related metabolic pathways (metabolites involved in this metabolic pathway) between TCN and CSN treatments were Phenylalanine, tyrosine and tryptophan biosynthesis (L-Tryptophane, Shikimic acid 3-phosphate Prephenate, Chorismate, L-Tryptophan and 3-Dehydroquinic acid), Flavone and flavonol biosynthesis (Isoquercitroside, Kaempferol-3-O-rutinoside, Syringetin, Rutinoside) and Syringetin, Rutin, Kaempferol and Lampranthin II) and lsoflavonoid biosynthesis (Medicocarpin, Xenognosin B, Naringenin, Daidzein and Genistein)(Fig. 7.b), respectively. PICRUSt results also showed that Flavone and flavonol biosynthesis function was upregulated in TCN treatment which compared to CSN treatment (Fig. 7.c).
In addition, three significantly related metabolic pathways (metabolites involved in this metabolic pathway) between TCR and CSR treatments were Alanine, aspartate and glutamate metabolism (L-Alanine, Argininosuccinic acid, L-Glutamine and Aspartic Acid), Sphingolipid metabolism (Sphinganine, Sphingosine, Dihydroceramide, Phytosphingosine and L-Serine) and Glycine, serine and threonine metabolism (4-Acetamido-2-aminobutanoic acid, L-Tryptophane, L-Aspartate-semialdehyde, L-Threonine, L-Tryptophan, L-Serine and Aspartic Acid)(Fig. 7e), respectively. Similarly, Alanine, aspartate and glutamate metabolisms were upregulated in the TCR treatment which compared to the CSN treatment(Fig. 7.f).
Correlation analysis between microbial and metabolite characteristics can contribute to understand the microbial community composition and function. To elucidate the relationship between soil microbes in rhizospheres of sugarcanes and root metabolites, spearman correlation analysis between top abundance 15 microbes and metabolites at the genus level was performed. The results showed that a strong correlation between root metabolites and soil microorganisms in rhizospheres of sugarcanes was found under different propagation methods.
Additionally, in comparison with CSN treatment, Arthrobacter, Bradyrhizobium, norank_f_Roseiflexaceae, Exophiala, Rhizoctonia and Chaetosphaeria significantly enriched in the TCN treatment (Fig. 7a.b).Of these, Arthrobacter was positively correlated with 3-Dehydroquinic acid and negatively correlated with Rutin; Bradyrhizobium was positively correlated with Shikimic acid 3-phosphate and Genistein; Meanwhile, it was negatively correlated with L-Tryptophan ; Moreover, norank_f_Roseiflexaceae was positively correlated with Naringenin, Prephenate, 3-Dehydroquinic acid, Isoquercitroside, LampranthinII, Chorismate and Kaempferol, and L -Tryptophan and Kaempferol-3-O-rutinoside were negatively correlated. Furthermore, Exophiala was positively correlated with Prephenate, 3-Dehydroquinic acid, Lampranthin II, Chorismate and Kaempferol, and it was also negatively correlated with Daidzein and Kaempferol-3-O- rutinoside; Rhizoctonia was positively correlated with Prephenate, Naringenin, Isoquercitroside, 3-Dehydroquinic acid, Lampranthin II, Chorismate and Kaempferol, and negatively correlated with L -Tryptophane, L-Tryptophan and Daidzein; in addition, Chaetosphaeria was positively correlated with Syringetin and it was negatively correlated with Rutin.
Similarly, in comparison with CSR treatment, unclassified_k_Fungi and Acremonium significantly enriched in the TCR treatment. Among them, unclassified_k_Fungi was positively correlated with Rutin, Kaempferol-3-O-rutinoside and Daidzein and it was also negatively correlated with Prephenate; Acremonium was positively correlated with Argininosuccinic acid, L-Alanine, L Serin and Phytosphingosinee.