甘蔗宿根矮化病感病与非感病株根际土壤生物学性状及细菌群落结构特征

目的]比较甘蔗宿根矮化病(ratoon stunting disease,RSD)感病植株与非感病植株根际土壤的生物学性状及细菌群落结构特征,旨在为构建甘蔗健康的根际微环境,筛选高效RSD生防细菌提供参考。方法]通过田间调查和实验室鉴定,以甘蔗RSD感病植株为试材,非感病植株为对照,采集甘蔗RSD感病植株和非感病植株的根际土壤,并基于传统和现代高通量测序技术,分析了甘蔗RSD感病植株和非感病植株根际土壤的生物学性状和细菌群落结构特征。结果]与甘蔗RSD非感病植株相比,感病植株根际土壤中指示土壤肥力与健康状况的生物学性状指标β-葡糖苷酶、磷酸酶和氨肽酶活性,以及微生物生物量碳、氮、磷显著降低;同时,指示细菌丰富度的Chao1指数和指示细菌多样性的Shannon指数显著下降。门分类水平与非感病甘蔗植株相比,RSD感病植株根际土壤中Proteobacteria(变形杆菌门)、Actinobacteria(放线菌门)、Gemmatimonadetes(芽单胞菌门)和Nitrospirae(硝化螺旋菌门)等优势门类细菌占比呈倍级降低,但Chloroflexi(绿弯菌门)、Acidobacteria(酸杆菌门)、Firmicutes(厚壁菌门)、Cyanobacteria(蓝细菌门)、Planctomycetes(浮霉菌门)、Bacteroidetes(拟杆菌门)等优势门类细菌占比呈倍级增加;在属分类水平,与非感病甘蔗植株相比,RSD感病植株根际土壤中Xanthobacteraceae(黄色杆菌属)、Acidothermus、Gaiellales、Roseiflexus(玫瑰菌属)、Micromonosporaceae(小单孢菌属)和Nitrospira(硝化螺旋菌属)细菌占比呈倍级降低,但Acidobacteria(嗜酸菌属)细菌及部分未知菌属却呈倍级提高。结论]甘蔗RSD感病植株根际微环境中指示土壤肥力的生物学指标显著降低,细菌丰富度和多样性显著下降,部分优势细菌门属占比发生剧变可能是导致甘蔗RSD发生的重要原因。

Soil biological properties and bacterial community structures in rhizosphere soil of canes infected and non-infected by ratoon stunting disease

【Objectives】The biological properties and bacterial communities in the rhizosphere of canes infected and non-infected with ratoon stunting disease (RSD) were compared for effective bio-control of the RSD in sugarcanes.【Methods】The cane plant and their rhizosphere soil were identified for infection of RSD firstly in lab. The cane plant and rhizosphere soil samples infected and non-infected by RSD were collected, respectively. The soil biological properties and bacterial community were determined by traditional and high throughput sequencing techniques.【Results】Compared with healthy soil, the activities of β-glucosidase, phosphatase and aminopeptidase in RSD infected soils were significantly inhibited, and the contents of soil microbial biomass carbon, nitrogen and phosphorus were significantly decreased, and the indexes of bacterial diversity and richness including Chao1, Shannon were significantly decreased as well. As for individual bacteria community on phylum level, the ratios of Proteobacteria, Actinobacteria, Gemmatimonadetes and Nitrospirae were all significantly decreased, while those of Chloroflexi, Acidobacteria, Firmicutes, Cyanobacteria, Planctomycetes and Bacteroidetes were significantly increased in rhizospheres of RSD infected canes. On genus level, the ratios of Xanthobacteraceae, Acidothermus, Gaiellales, Roseiflexus, Micromonosporaceae and Nitrospira were significantly decreased, while those of Acidobacteria and unclassified bacteria were significantly increased in rhizospheres of RSD infected canes.【Conclusions】In rhizosphere soils of RSD infected canes, the activities of important soil enzymes and microbial mass carbon, nitrogen and phosphorous contents are low, the diversity and the richness bacterial community are significantly decreased. On the phylum and genus levels, great variations in the abundance of the dominant bacteria have been confirmed.