Liu Xiaojiao, Liu Liehua, Gong Jie, Zhang Lixin, Jiang Qipeng, Huang Kuo, Ding Wei
State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding in Ministry of Agriculture, College of Sericulture, Textile and Biomass Science, Southwest University, Chongqing, 400715, China.
Microecological Process and Regulation Key Laboratory, College of Plant Protection, Southwest University, Chongqing, 400715, China.
AMB Express. 2022 Aug 29;12(1):110. doi: 10.1186/s13568-022-01455-1.
Natural soil has the ability to suppress the soil-borne pathogen to a certain extent, and the assemblage of soil microbiome plays a crucial role in maintaining such ability. Long-term monoculture accelerates the forms of soil microbiome and leads to either disease conducive or suppressive soils. Here, we explored the impact of soil conditions on bacterial wilt disease (healthy or diseased) under long-term tobacco monoculture on the assemblage of bacterial and fungal communities in bulk and rhizosphere soils during the growth periods. With Illumina sequencing, we compared the bacterial and fungal composition of soil samples from tobacco bacterial wilt diseased fields and healthy fields in three growth periods. We found that Proteobacteria and Ascomycota were the most abundant phylum for bacteria and fungi, respectively. Factors of soil conditions and tobacco growth periods can significantly influence the microbial composition in bulk soil samples, while the factor of soil conditions mainly determined the microbial composition in rhizosphere soil samples. Next, rhizosphere samples were further analyzed with LEfSe to determine the discriminative taxa affected by the factor of soil conditions. For bacteria, the genus Ralstonia was found in the diseased soils, whereas the genus Flavobacterium was the only shared taxon in healthy soils; for fungi, the genus Chaetomium was the most significant taxon in healthy soils. Besides, network analysis confirmed that the topologies of networks of healthy soils were higher than that of diseased soils. Together, our results suggest that microbial assemblage in the rhizosphere will be largely affected by soil conditions especially after long-term monoculture.
天然土壤具有一定程度抑制土传病原菌的能力，而土壤微生物群落的组合在维持这种能力方面起着关键作用。长期连作会加速土壤微生物群落的形成，导致土壤要么利于发病，要么具有抑制病害的能力。在此，我们探究了长期烟草连作下土壤状况（健康或患病）对生长期间烟株根际土壤和非根际土壤中细菌和真菌群落组合的影响。通过Illumina测序，我们比较了三个生长时期烟草青枯病发病田和健康田土壤样品的细菌和真菌组成。我们发现，变形菌门和子囊菌门分别是细菌和真菌中最丰富的菌门。土壤状况和烟草生长时期的因素能显著影响非根际土壤样品中的微生物组成，而土壤状况因素主要决定根际土壤样品中的微生物组成。接下来，利用线性判别分析效应大小（LEfSe）对根际样品进行进一步分析，以确定受土壤状况因素影响的判别分类群。对于细菌，在患病土壤中发现了劳尔氏菌属，而黄杆菌属是健康土壤中唯一共有的分类群；对于真菌，毛壳菌属是健康土壤中最显著的分类群。此外，网络分析证实健康土壤网络的拓扑结构高于患病土壤。总之，我们的结果表明，尤其是在长期连作后，根际微生物组合将受到土壤状况的很大影响。
