Engineering and Research Center of Sustainable Development and Utilization of Bioenergy, Ministry of Education, Yunnan Normal University, Kunming, China.
Yunnan Research Center of Biogas Technology and Engineering, School of Energy and Environment Science, Yunnan Normal University, Kunming, China.
PeerJ. 2022 Jul 26;10:e13770. doi: 10.7717/peerj.13770. eCollection 2022.
is an important herbal medicine in China, where this crop is cultivated by replanting of seedlings. Root rot disease threatens the sustainability of cultivation. Water flooding (WF) is widely used to control numerous soilborne diseases, and biogas slurry shows positive effects on the soil physiochemical properties and microbial community structure and has the potential to suppress soilborne pathogens. Hence, biogas slurry flooding (BSF) may be an effective approach for alleviating root rot disease of ; however, the underlying mechanism needs to be elucidated.
In this study, we conducted a microcosm experiment to determine if BSF can reduce the abundance of pathogens in soil and, alleviate root rot of . Microcosms, containing soil collected from a patch of showing symptoms of root rot disease, were subjected to WF or BSF at two concentrations for two durations (15 and 30 days), after which the changes in their physicochemical properties were investigated. Culturable microorganisms and the root rot ratio were also estimated. We next compared changes in the microbial community structure of soils under BSF with changes in WF and untreated soils through high-throughput sequencing of bacterial 16S rRNA (16S) and fungal internal transcribed spacer (ITS) genes amplicon.
WF treatment did not obviously change the soil microbiota. In contrast, BSF treatment significantly altered the physicochemical properties and reshaped the bacterial and fungal communities, reduced the relative abundance of potential fungal pathogens (, , , and ), and suppressed culturable fungi and . The changes in the microbial community structure corresponded to decreased root rot ratios. The mechanisms of fungal pathogen suppression by BSF involved several factors, including inducing anaerobic/conductive conditions, altering the soil physicochemical properties, enriching the anaerobic and culturable bacteria, and increasing the phylogenetic relatedness of the bacterial community.
BSF application can reshape the soil microbial community, reduce the abundance of potential pathogens, and alleviate root rot in . Thus, it is a promising practice for controlling root rot disease in .
是中国的一种重要草药，这种作物通过幼苗移栽进行种植。根腐病威胁着 的可持续种植。水涝（WF）广泛用于控制许多土传病害，沼气液对土壤理化性质和微生物群落结构有积极影响，并有抑制土传病原菌的潜力。因此，沼气液灌溉（BSF）可能是缓解 的根腐病的有效方法；然而，其潜在机制尚需阐明。
本研究通过微宇宙实验，确定 BSF 是否可以降低土壤中病原菌的丰度，从而缓解 根腐病。微宇宙由来自表现出根腐病症状的 斑块的土壤组成，在两种浓度下进行 WF 或 BSF 处理，持续时间为 15 天和 30 天，然后测量其理化性质的变化。还估计了可培养微生物和根腐病的比例。接下来，通过细菌 16S rRNA（16S）和真菌内部转录间隔区（ITS）基因扩增子高通量测序，比较了 BSF 下土壤微生物群落结构的变化与 WF 处理和未处理土壤的变化。
WF 处理对土壤微生物群没有明显影响。相比之下，BSF 处理显著改变了理化性质，重塑了细菌和真菌群落，降低了潜在真菌病原菌（、、、和）的相对丰度，抑制了可培养真菌和。微生物群落结构的变化与根腐病比例的降低相对应。BSF 抑制真菌病原菌的机制涉及多个因素，包括诱导厌氧/导电条件、改变土壤理化性质、富集厌氧和可培养细菌、以及增加细菌群落的系统发育相关性。
BSF 应用可以重塑土壤微生物群落，降低潜在病原菌的丰度，缓解 的根腐病。因此，它是控制 的根腐病的一种有前途的做法。
