烟草黑胫病植株根际土壤真菌群落多样性及结构分析

Diversity and structure of the fungal community in rhizosphere soil of tobacco plants with black shank disease

【目的】为改善云南烟区植烟土壤微生态环境及从土壤生防菌筛选等角度防治烟草黑胫病提供基础数据及理论依据。【方法】采用Illumina MiSeq高通量测序技术分析了健康与患病烟株根际土壤真菌群落结构。【结果】健康烟株根际土壤(ZCTY)和患病烟株根际土壤(HJTY)真菌OTU数分别为1809和1479个,同时ZCTY的OTU数、特有OTU数分别是HJTY的1.22、1.62倍,且HJTY中的真菌物种量、丰富度和多样性显著降低,ACE、Chao1和Shannon指数较ZCTY分别降低了31.87%、30.47%和0.68%;同时,优势种属中的Soilcoccozyma、镰刀菌属(Fusarium)、Spiromastix和青霉属(Penicillium)在两组间存在显著差异,较ZCTY相比,HJTY中的Soilcoccozyma、镰刀菌属和青霉属相对丰度分别增加了177.06%、54.32%和144.27%,而毛壳菌属(Chaetomium)等有益菌属显著减少,且Spiromastix是HJTY的特有菌属;烟株根际土壤真菌群落与土壤理化因子(pH、有机质、碱解氮、有效磷、速效钾)变化存在一定的相关性,其中油壶菌属与有机质、碱解氮均呈显著负相关,镰刀菌属与碱解氮呈显著正相关,Soilcoccozyma与pH呈显著负相关,与速效钾呈显著正相关,Plectosphaerella与碱解氮、有效磷呈显著负相关,而青霉菌属与碱解氮、有效磷呈显著正相关,外瓶柄霉属(Exophiala)与有机质呈显著正相关。【结论】烟株根际土壤真菌多样性、丰富度的降低及群落结构的改变是烟株患黑胫病后的重要指征之一,其中镰刀菌属、被孢霉属(Mortierella)、青霉属等相关病原菌及腐生菌显著增加,毛壳菌属等有益菌属显著减少,且根际土壤真菌群落受到土壤微生态环境中生物因子和非生物因子的共同影响。

【Objective】The present paper aimed to provide basic data and theoretical basis for improving the micro-ecological environment of tobacco planting soil in Yunnan tobacco and to control tobacco black shank disease from the perspective of soil biocontrol bacteria screening.【Method】The fungal community structure of rhizosphere soil of healthy and diseased tobacco plants was analyzed by Illumina MiSeq high-throughput sequencing technology.【Result】The number of fungal OTUs in the rhizosphere soil of healthy tobacco plants(ZCTY) and diseased tobacco plants(HJTY) were 1809 and 1479, respectively. Moreover, the number of OTUs and unique OTUs of ZCTY were 1.22 and 1.62 times of HJTY, respectively. The abundance, richness, and diversity of fungi in HJTY were significantly reduced. ACE, Chao1 and Shannon indexes were reduced by 31.87%, 30.47%, and 0.68% compared with ZCTY. Meanwhile, in the dominant genera Soilcoccozyma, Fusarium, Spiromastix, and Penicillium were significantly different between the two groups. Compared with ZCTY, the relative abundance of Soilcoccozyma, Fusarium, and Penicillium in HJTY increased by 177.06%, 54.32%, and 144.27%, respectively. While the beneficial bacteria genera such as Chaetomium decreased significantly, Spiromastix was a unique genus in HJTY. There were a certain correlations between the soil fungal community in the rhizosphere of tobacco plants and the changes of soil physicochemical factors(pH, organic matter, alkali hydrolyzable nitrogen, effective phosphorus and available potassium). Among them, Olpidium fungus was significantly negatively correlated with organic matter and alkali hydrolyzable nitrogen. Fusarium was positively correlated with alkali hydrolyzable nitrogen. Soilcoccozyma was significantly negatively correlated with pH and positively correlated with available potassium.Plectosphaerella was significantly negatively correlated with alkali hydrolyzable nitrogen and effective phosphorus. Penicillium was significantly positively correlated with alkali hydrolyzable nitrogen and effective phosphorus. And Exophiala was significantly positively correlated with organic matter.【Conclusion】The reduction of fungal diversity and richness, and the change of community structure in the rhizosphere soil of tobacco plants were one of the important indicators of black shank disease in tobacco plants. Among them, Fusarium, Mortierella, Penicillium and other related pathogenic and saprophytic fungi increased significantly, the beneficial fungi such as Chaetomium decreased significantly. And the rhizosphere soil fungal community was affected by both biotic and abiotic factors in the soil micro-ecological environment.