温郁金连作和熏蒸处理土壤微生物种群数量分析

Analysis of the Microbial Communities and Populations in Soils with Continuous Cropping of Curcuma wenyujin and Fumigation

【目的】明确温郁金连作和熏蒸土壤中微生物种群结构,为缓解温郁金连作障碍奠定基础。【方法】选择温郁金连作3年的土壤,在播种前1个月,用棉隆进行土壤熏蒸处理,在温郁金种植7个月后,分别取连作、棉隆熏蒸及未种植温郁金地块等3种土壤,提取土壤总DNA,通过PacBio Sequel微生物3代测序手段,分析土壤真菌及细菌种群数量及多样性。【结果】土壤经熏蒸处理种植的温郁金植株长势好,病害发生少,而连作种植的温郁金植株长势差,死苗较多。细菌群落属水平的分析结果表明,与未种植土壤比较,连作根际土壤中的AD3、TK10和WPS-2的丰度降低。熏蒸土壤中,芽孢杆菌属(Bacillus)和鞘脂单胞菌属(Sphingomonas)等一些具有生防功能的细菌丰度增加。在3种土壤中,有5个真菌门类丰度较高,分别为子囊菌门(Ascomycota)、担子菌门(Basidiomycota)、壶菌门(Chytridiomycota)、被孢菌门(Mortierellomycota)以及未分类真菌门(unclassified_k_Fungi)。其中子囊菌门真菌在未种植土壤中丰度最低,连作使子囊菌门真菌的丰度显著升高、担子菌门真菌的丰度显著降低。大量有益的真菌属,如毛壳菌属(Chaetomium)、青霉属(Penicillium)、曲霉属(Aspergillus)、漆斑菌属(Myrothecium)、梭孢壳霉属(Thielavia)、腐质霉属(Humicola)、Rhizophlyctis、Microdochium、Ramicandelaber、Albifimbria、Curvularia、巨孢囊霉属(Gigaspora)、黑孢菌属(Nigrospora)、Neocosmospora、Talaromyces、Roussoella、Rhytidhysteron、Boothiomyces、Apiotrichum、Ochroconis、Saitozyma、丝孢酵母属(Trichosporon)、茎点霉属(Phoma)等在熏蒸土壤中的丰度明显高于连作土壤。而在连作土壤中则表现为较多的致病微生物的累积。【结论】温郁金连作可使土壤有害微生物的积累,造成温郁金连作障碍,施用棉隆熏蒸处理土壤后,可减少土壤中病原菌的数量,增加有益微生物种群数量,削减温郁金的连作障碍。

【Objective】The study was conducted to clarify the microbial community structure in soil with continuous cropping of Curcuma wenyujin and fumigation treatment,aiming to lay a foundation for alleviating continuous cropping obstacles in C.wenyujin cultivation.【Method】The soil under a continuous cropping of C.wenyujin for 3 years was selected and fumigated with dazomet one month before planting C.wenyujin.After 7-month cultivation of C.wenyujin,we collected soil samples from three types of plots:continuous cropping,fumigated and uncultivated.Total soil DNA was extracted,and the population and diversity of microbial communities(fungi and bacteria)were analyzed by using PacBio Sequel third-generation sequencing.【Result】The results showed that C.wenyujin plants in the fumigated soil exhibited good growth and minimal disease incidence,while those in the continuous cropping soil had poor growth and severe seedling death.Analysis of bacterial communities at the phylum level revealed that the abundance of AD3,TK10 and WPS-2 decreased in rhizosphere soil after continuous cropping compared with those in uncultivated soil.Fumigation of continuous cropping soil increased the abundance of beneficial bacteria with biocontrol functions such as Bacillus and Sphingomonas.Among the three soil types,5 fungal phyla were abundant,including Ascomycota,Basidiomycota,Chytridiomycota,Mortierellomycota,and unclassified_k_Fungi.Ascomycota had the lowest abundance in uncultivated C.wenyujin soil,but continuous cropping significantly increased its abundance,while Basidiomycota showed a significant decrease.Several beneficial fungal genera,including Chaetomium,Penicillium,Aspergillus,Myrothecium,Thielavia,Humicola,Rhizophlyctis,Microdochium,Ramicandelaber,Albifimbria,Curvularia,Gigaspora,Nigrospora,Neocosmospora,Talaromyces,Roussoella,Rhytidhysteron,Boothiomyces,Apiotrichum,Ochroconis,Saitozyma,Trichosporon and Phoma,had higher abundance in fumigated soil than that in continuous cropping soil.In contrast,continuous cropping soil had a higher accumulation of pathogenic microorganisms.【Conclusion】Continuous cropping of C.wenyujin leads to the accumulation of harmful soil microorganism,resulting in continuous cropping obstacles.Fumigation with dazomet can reduce the number of soil-borne pathogens and increase the abundance of beneficial microbial populations,thereby mitigating continuous cropping obstacles in C.wenyujin cultivation.