基于ITS序列的百香果宿根连作根际土壤真菌群落变化研究

Analysis on the Changes of Fungal Community in Rhizosphere Soil of Passiflora Edulia by Continuous Cropping of Perennial Roots Based on ITS Sequences

以不同宿根年限百香果根际土壤为研究材料,运用ITS序列测序技术,揭示宿根连作对百香果根际土壤微生物群落结构变化的影响。结果表明:宿根连作百香果根际土壤共测得513420条有效序列,其中注释为5346个操作分类单元(Operational Taxonomic Units,OTUs)。α多样性指数表明,百香果根际土壤真菌群落的Chao1指数、Observed species指数、Simpson指数和Shannon指数随宿根连作年份增加而下降。β多样性指数表明,根际土壤正茬与重茬之间真菌群落多样性差异比较大。在属水平的优势真菌热图分析表明,宿根连作百香果根际土壤真菌群落结构有一定差异,随着百香果宿根年限增加,柱孢属Cylindrocarpon和炭疽菌属Colletotrichum的相对丰度呈上升趋势;与之相反,被孢霉属Mortierella、木霉菌属Trichoderma和小不整球壳属Plectosphaerella随宿根年限增加而下降;其中,与有益真菌相关的被孢霉属Mortierella相对丰度随宿根年限增加而减少81.64%,而柱孢属Cylindrocarpon和炭疽菌属Colletotrichum的相对丰度随之增加了78.57%和78.05%。因此,百香果连作障碍可能是由根际土壤生态系失衡导致。

By taking the rhizosphere soil of Passiflora edulia with different perennial root years as the research material,the effects of continuously ratooning on the structural changes of microbial communities in the rhizosphere soil of Passiflora edulia were revealed by using the ITS sequencing technology.The results showed that a total of 513420 effective sequences were measured in the rhizosphere soil of Passiflora edulia,among which 5346 Operational Taxonomic Units were annotated.Theαdiversity index showed that the Chao1 index,Observed species index,Simpson index and Shannon index of fungal communities in the rhizosphere soil of Passiflora edulia decreased with the year increase of continuous ratooning.Theβ-diversity index showed that the diversity of fungal communities in the rhizosphere soil was significantly different between the main crop in crop rotation and the continuous cropping.Through the heatmap analysis of dominant fungi at the genus level,there were some differences in the structures of fungal community in the rhizosphere soil of Passiflora edulia with continuously ratooning.With the year increase of perennial roots of Passiflora edulia,the relative abundance of Cylindrocarpon and Colletotrichum showed an increasing trend,while the relative abundance of Mortierella,Trichoderma and Plectosphaerella decreased with the year increase of perennial roots.Among them,the relative abundance of Mortierella related to beneficial fungi decreased by 81.64%with the year increase of perennial roots,while the relative abundance of Cylindrocarpon and Colletotrichum increased by 78.57%and 78.05%.Therefore,the obstacle for the continuous ratooning of Passiflora edulia might be caused by the ecological unbalance of the rhizosphere soil.