黄土高原旱作区马铃薯连作根际土壤微生物群落变化特征

Characteristics of microbial community in the rhizosphere soil of continuous potato cropping in arid regions of the Loess Plateau

本文探讨了土壤微生物对马铃薯连作的响应,旨在揭示连作土壤退化的微生物特征。采用盆栽试验和MiSeq高通量测序技术相结合的方法,以休耕(CK)和轮作(R_rh)为对照,研究了马铃薯连作1年(1_rh)、3年(3_rh)和5年(5_rh)根际土壤微生物群落特征。结果表明,与CK和轮作相比,3_rh和5_rh土壤样品Ace指数、Chao指数、Shannon指数显著降低。与轮作相比,马铃薯连作土壤细菌中变形菌门(Proteobacteria)、放线菌门(Actinobacteria)和酸杆菌门(Acidobacteria)相对丰度较高,土壤真菌中子囊菌门(Ascomycota)相对丰度较低。细菌群落中,较轮作,1_rh、3_rh、5_rh气微菌属(Aeromicrobium)的数量分别增加258.01%、625.93%、76.04%,节杆菌属(Arthrobacter)分别增加245.42%、1258.12%、58.89%,链霉菌属(Streptomyces)分别增加203.83%、116.74%、311.61%。真菌群落中,较轮作,3_rh镰孢属(Fusarium)数量增加了225.00%,5_rh毛壳属(Chaetomium)数量降低了31.58%,1_rh、3_rh、5_rh久浩酵母属(Guehomyces)的数量分别降低55.40%,58.14%,78.37%;壶菌属(Spizellomyces)在休耕和轮作土壤中数量较多,而在连作3年和5年土壤中数量很少,接近检测底限。说明马铃薯长期连作降低了土壤微生物多样性,微生物优势种群发生改变,土壤微生物群落结构失衡。

The response of soil microorganisms to continuous cropping of potato was discussed in this study,aiming at revealing the microbial characteristics of continuous cropping soil degradation.Pot experiments and MiSeq high-throughput sequencing technology were used to study the characteristics of microbial communities in the rhizosphere soil of potato continuous cropping for 1 year(1_rh),3 years(3_rh),and 5 years(5_rh),with fallow(CK)and rotation(R_rh)as controls.The results showed that compared with CK and rotation,Ace index,Chao index,and Shannon index of 3_rh and 5_rh soil samples decreased significantly.Compared with rotation,the relative abundance of Proteobacteria,Actinobacteria,and Acidobacteria in soil bacteria of continuous potato cropping was higher,while the relative abundance of Ascomycota in soil fungi was lower.In the bacterial community,compared with rotation,the number of Aeromicrobium in 1_rh,3_rh,5_rh increased by 258.01%,625.93%,76.04%,Arthrobacter increased by 245.42%,1258.12%,58.89%,Streptomyces increased by 203.83%,116.74%,and 311.61%,respectively.In the fungal community,compared with rotation,the number of Fusarium in 3_rh increased by 225.00%,the number of Chaetomium in 5_rh decreased by 31.58%,and the number of Guehomyces in 1_rh,3_rh,and 5_rh decreased by 55.40%,58.14%,and 78.37%,respectively.Spizellomyces had a large number in fallow and rotation soils,but a small number in continuous cropping soils for three years and five years,which was close to the detection limit.The results indicated that long-term continuous cropping of po-tato reduced the diversity of soil microorganisms,changed the dominant population of microorganisms,and unbalanced the struc-ture of soil microbial community.