We explored the effects of addition of sorghum stubble rhizosphere soil on the growth of continuous cropping cucumber and rhizosphere microbial community in a pot experiment. The diffe-rences in soil bacterial and fungal community composition were analyzed with fluorescence quantitative PCR and high-throughput sequencing technology. There were four treatments: CK (no fertilization), T1(fertilizer only), T2(optimized fertilization), and T3(optimized fertilization + rhizosphere soil of sorghum stubble). The results showed that compared with other treatments, T3 promoted the growth and development of cucumber, and increased the abundance of 16S rRNA and ITS rRNA genes in soil. Compared with the T1 treatment, T2 and T3 significantly increased the richness and diversity of bacterial communities. There was no significant difference in fungal community richness and diversity among different treatments. Adding rhizosphere soil of sorghum stubble changed the composition of bacterial and fungal communities at both phylum and genus levels. For bacteria, it increased the abundances of Acidobacteria and Bacteroides, but decreased that of Proteobacteria, Firmicutes, Nitrospira and Bacillus. For fungi, it increased the abundance of Basidiomycota, Trichoderma and Pseudurotium, but decreased that of Fusarium and Metarhizium. Results of redundancy analysis showed that soil nitrate and organic matter were the key factors affecting the difference of bacterial and fungal community composition, respectively. In conclusion, addition of sorghum stubble rhizosphere soil improved the total abundance of soil microorganisms and bacterial diversity for continuous cropping cucumber. It increased the abundance of beneficial bacteria Trichoderma, reduced that of pathogenic Fusarium, and maintained the survival rate of cucumber, thus provided a feasible solution for alleviating the barriers for the continuous cropping of cucumber.
为了分析添加高粱根茬根际土对连作黄瓜生长和根际微生物群落特征的影响,本研究通过盆栽试验,采用荧光定量PCR和高通量测序技术分析土壤细菌和真菌群落组成的差异。试验共设4个处理: CK(不施肥),T1(单施化肥),T2(优化施肥),T3(优化施肥+高粱根茬根际土)。结果表明: 与其他处理相比,T3处理促进了黄瓜生长发育,提高了土壤中16S rRNA和ITS rRNA基因数量。与T1处理相比,T2和T3处理明显提高了细菌群落的丰富度和多样性,不同处理间真菌群落的丰富度和多样性差异不明显。添加高粱根茬根际土在一定程度上改变了基于门、属水平上的细菌和真菌群落结构。其中,细菌中提高了酸杆菌门和拟杆菌门的丰度,降低了变形菌门、厚壁菌门、硝化螺旋菌门和芽孢杆菌属的丰度;真菌中提高了担子菌门、木霉菌属和假散囊菌属的丰度,降低了镰刀菌属和绿僵菌属的丰度。冗余分析表明,土壤硝态氮和有机质含量分别是影响细菌和真菌群落结构差异的关键因子。添加高粱根茬根际土不仅提高了连作黄瓜土壤微生物数量和细菌多样性,而且增加了有益菌木霉菌属的丰度,降低了致病镰刀菌的丰度和数量,保障了黄瓜存活率,为缓解黄瓜连作障碍提供了一条切实可行的解决途径。.
Keywords: bacteria; continuous cropping obstacle; fungi; microbial community.