The ultimate purpose of phytoextraction is not only to remove heavy metals from soil but also to improve soil quality.Here, we evaluated how the joint effect of Streptomyces pactum(strain Act12) and inorganic(Hoagland...The ultimate purpose of phytoextraction is not only to remove heavy metals from soil but also to improve soil quality.Here, we evaluated how the joint effect of Streptomyces pactum(strain Act12) and inorganic(Hoagland’s solution) and organic(humic acid and peat) nutrients affected the phytoextraction practice of cadmium(Cd) and zinc(Zn) by potherb mustard, and the microbial community composition within rhizosphere was also investigated.The results indicated that the nutrients exerted synergistically with Act12, all increasing the plant biomass and Cd/Zn uptakes.The inoculation of Act12 alone significantly increased dehydrogenase activity of rhizosphere soil(P<0.05), while urease and alkaline phosphatase activities varied in different dosage of Act12.Combined application of microbial strain with nutrients increased enzymatic activities with the elevated dosage of Act12.16S ribosomal RNA high-throughput sequencing analysis revealed that Act12 inoculation reduced the diversity of rhizosphere bacteria.The Act12 and nutrients did not change dominant phyla i.e.,Proteobacteria, Bacteroidetes, Gemmatimonadetes, Actinobacteria and Acidobacteria, but their relative abundance differed among the treatments with: Peat>Act12>Humic acid >Hoagland’s solution.Comparatively, Sphingomonas replaced Thiobacillus as dominant genus after Act12 application.The increase in the Sphingomonas and Flavisolibacter abundances under Act12 and nutrients treatments gave rise to growth-promoting effect on plant.Our results revealed the important role for rhizosphere microbiota in mediating soil biochemical traits and plant growth, and our approach charted a path toward the development of Act12 combined with soil nutrients to enhance soil quality and phytoextraction efficiency in Cd/Zn-contaminated soils.展开更多
采用琼脂块法及抑菌试验,研究了多功能放线菌Act12对6种常见土传病原真菌的拮抗作用;采用形态特征、生理生化特性及16 S rDNA序列分析,确定了Act12的分类地位。结果表明,Act12对6种供试土传病原真菌具有不同程度的拮抗作用,其中,对木贼...采用琼脂块法及抑菌试验,研究了多功能放线菌Act12对6种常见土传病原真菌的拮抗作用;采用形态特征、生理生化特性及16 S rDNA序列分析,确定了Act12的分类地位。结果表明,Act12对6种供试土传病原真菌具有不同程度的拮抗作用,其中,对木贼镰刀菌(Fusarium equiseti)和尖孢镰刀菌西瓜专化型(F.ox-ysporum f.sp.niveum)的拮抗圈直径分别达到20.5 mm和18.4 mm;培养48 h,Act12无菌发酵滤液对木贼镰刀菌的抑菌率达到83.2%。菌株显微形态、培养特征、生理生化特性及16 S rDNA序列分析结果表明,多功能放线菌Act12为链霉菌属的密旋链霉菌(Streptomyces pactum)。展开更多
基金supported by the Fundamental Research Funds for the Central Universities of China (Nos. 3102019JC007, G2021KY0601)。
文摘The ultimate purpose of phytoextraction is not only to remove heavy metals from soil but also to improve soil quality.Here, we evaluated how the joint effect of Streptomyces pactum(strain Act12) and inorganic(Hoagland’s solution) and organic(humic acid and peat) nutrients affected the phytoextraction practice of cadmium(Cd) and zinc(Zn) by potherb mustard, and the microbial community composition within rhizosphere was also investigated.The results indicated that the nutrients exerted synergistically with Act12, all increasing the plant biomass and Cd/Zn uptakes.The inoculation of Act12 alone significantly increased dehydrogenase activity of rhizosphere soil(P<0.05), while urease and alkaline phosphatase activities varied in different dosage of Act12.Combined application of microbial strain with nutrients increased enzymatic activities with the elevated dosage of Act12.16S ribosomal RNA high-throughput sequencing analysis revealed that Act12 inoculation reduced the diversity of rhizosphere bacteria.The Act12 and nutrients did not change dominant phyla i.e.,Proteobacteria, Bacteroidetes, Gemmatimonadetes, Actinobacteria and Acidobacteria, but their relative abundance differed among the treatments with: Peat>Act12>Humic acid >Hoagland’s solution.Comparatively, Sphingomonas replaced Thiobacillus as dominant genus after Act12 application.The increase in the Sphingomonas and Flavisolibacter abundances under Act12 and nutrients treatments gave rise to growth-promoting effect on plant.Our results revealed the important role for rhizosphere microbiota in mediating soil biochemical traits and plant growth, and our approach charted a path toward the development of Act12 combined with soil nutrients to enhance soil quality and phytoextraction efficiency in Cd/Zn-contaminated soils.
