土壤微生态在西瓜枯萎病发病过程中的变化研究

Study on Pathogenesis of Watermelon Fusarium Wilt from Perspective of Soil

本研究旨在通过分析不同健康程度的西瓜植株根际土壤的微生态及化学性质来解析西瓜枯萎病的发病过程,为西瓜枯萎病的防治提供理论基础。通过检测西瓜根围土壤的有效氮、有效磷、有效钾、p H等化学性质,并利用高通量测序技术对其根际土壤微生物组进行测序,从而比较不同健康程度的西瓜根际土壤的差异。结果显示,健康、严重发病植株根际都形成了各自的较为稳定的有益、有害微生物网络,根际微生物组成分析显示其各自富集了有益、有害菌;而轻微发病根际致病菌、生防菌都出现特异性富集,且特征物种不同于健康、严重发病植株,轻微发病植株根际较高的微生物多样性提示,在生防菌的分离筛选时,选择轻微发病植株的根际土壤或许能获得丰度更高的生防资源。根际特征物种分析显示,金孢子菌属(Chrysosporiumsp.)、醋酸钙不动杆菌(Acinetobacter calcoaceticus)等可能在西瓜枯萎病的防治中发挥着重要作用。另外,土壤理化性质与土壤微生物α多样性关联分析结果显示,土壤理化性质与细菌丰度显著正相关。

This study is to explain the pathogenesis of watermelon Fusarium wilt by analyzing rhizosphere soil microbiome and chemical properties of watermelon plants with different health levels, and to provide a theoretical basis for the prevention and control of watermelon Fusarium wilt. The chemical properties of available nitrogen, phosphorus, potassium and pH in the soil around the watermelon roots were detected, rhizosphere soil microbiome was sequenced by high-throughput sequencing technology, and then the differences in rhizosphere soils of watermelons with different levels of health were compared. The results show that the healthy and severely ill plants have formed their own relatively stable networks of beneficial and harmful microorganisms, and both are enriched with beneficial and harmful bacteria;while pathogenic bacteria and biocontrol bacteria are specifically enriched in the minorly pathogenic rhizosphere, and the characteristic species are different from healthy and severely ill plants. The high rhizosphere microbial diversity of mildly affected plants suggests that when the separation and screening of biocontrol bacteria, the rhizosphere soil of the mildly pathogenic plants may be able to obtain more abundant biocontrol resources.Rhizosphere characteristic species analysis shows that Chrysosporium sp., A. calcoaceticus, etc. may play an important role in the prevention and control of watermelon Fusarium wilt. In addition, the correlation between soil physicochemical properties and microbial α-diversity shows that soil physicochemical properties are significantly positively correlated with bacterial abundance.