Influence of functionalized graphene on the bacterial and fungal diversity of Vicia faba rhizosphere soil

功能化石墨烯对蚕豆根际土壤细菌和真菌多样性的影响

The effect of functionalized graphene on the growth and development of Vicia faba L.was investigated by analyzing its impact on the composition and diversity of the microbial community in rhizosphere peat soil.Seedlings of V.faba planted in this peat soil were treated with either distilled water(CK)or 25 mg·L^(−1)(G25)of functionalized graphene solution.Results showed that the height and root length of V.faba seedlings in the G25 group were significantly larger than those in CK group.The microbial com-munity was analyzed by amplifying and sequencing the 16S rRNA gene V_(3)-V_(4) region of bacteria and internal transcribed spacer re-gion of fungi in rhizosphere soil using Illumina MiSeq technology.Alpha and beta diversity analysis indicated that functionalized graphene increased the richness and diversity of bacteria and fungi in the V.faba rhizosphere peat soil.The abundances of three ni-trogen cycling-related bacteria,Hydrogenophaga,Sphingomonas and Nitrosomonadaceae,were also altered after treatment with the functionalized graphene.The relative abundance of Basilicum,related to soil phosphorus solubilization,decreased in the fungal com-munity,while the relative abundance of Clonostachys and Dimorphospora,which exhibited strong biological control over numerous fungal plant pathogens,nematodes and insects,increased in the soil after functionalized graphene treatment.Redundancy analysis re-vealed that the potential of hydrogen(pH),organic matter,and total phosphorus contributed the most to the changes in bacterial and fungal community composition in the rhizosphere soil.Overall,our findings suggested that the addition of functionalized graphene altered the relative abundances of nitrogen and phosphorus cycling-related microorganisms in peat soil,promoting changes in the physicochemical properties of the soil and ultimately leading to the improved growth of V.faba plants.

功能化石墨烯的亲水、吸附性能优异,在农业领域应用广泛。如用于农作物的缓释肥、鲜切花的抗菌剂、杀虫剂的载体等。本研究从功能化石墨烯对蚕豆根际泥炭土微生物群落组成和多样性的影响方面入手,探索功能化石墨烯对蚕豆生长发育的机理。利用蒸馏水和25 mg·L^(-1)的功能化石墨烯溶液培养种植于泥炭土的蚕豆幼苗。实验组蚕豆幼苗株高和根长显著高于空白组。利用高通量测序技术对土壤中细菌的16S rRNA基因(V_(3)–V_(4)区)和真菌内转录间隔区序列(ITS2区)进行扩增测序,聚类得到9144个细菌OTUs,归类于39个门及350个属;得到790个真菌OTUs,归类于18个门及156个属。根据alpha、beta多样性分析,功能化石墨烯可以增加蚕豆根际泥炭土中细菌和真菌的丰度和多样性,两组间细菌和真菌群落的差异显著,且真菌群落的差异大于细菌群落。细菌群落中噬氢菌属、鞘氨醇单胞菌属和亚硝化单胞菌科3种氮循环相关的细菌在经功能化石墨烯处理后,丰度发生改变,进而促进蚕豆生长。真菌群落中,与土壤溶磷功能相关的篮状菌属的相对丰度下降,而对多种植物真菌病原菌、线虫和昆虫具有较强的生物防治能力的真菌属Clonostachys、Dimorphospora相对丰度增加。最后通过冗余分析发现,pH值、有机质(OM)、全磷(TP)3个土壤理化因子对土壤中细菌和真菌群落组成改变的贡献最大。