生防菌剂链霉菌JD211对水稻土壤微生物群落结构及碳代谢的影响

Effect of Biocide Streptomyces JD211 on Soil Microbial Community Structure and Carbon Metabolism in Rice

【目的】水稻土作为重要的耕地土壤,但由于近些年来化肥和杀菌剂的过度使用已严重破坏水稻土壤的生态平衡。随着生物防治的推广应用,该难题得以控制,其中具抑菌潜力的植物内生菌已被广泛应用于土壤病害防治中。链霉菌JD211是一株自珙桐植株分离的潜在生防菌,通过探究其对水稻土壤微生物群落及碳代谢的影响为微生物肥料的作用机制提供研究思路。【方法】本研究以链霉菌JD211作为外源施加微生物,不加菌剂的水稻土为对照,分别添加占土壤总重的2%(B2)和4%(B4)菌剂为处理,采用气相色谱法测定土壤中CO_(2)的排放速率,低温外热重铬酸钾氧化-比色法测定土壤有机碳含量,并通过Biolog-ECO法分析土壤微生物群落代谢功能多样性。【结果】相较于对照组,不同含量生防菌剂的添加都显著增加了水稻土壤CO_(2)的排放速率和有机碳含量,B2、B4处理组土壤有机碳含量相较于CK组分别提高了19.25%、23.10%;三组处理的平均颜色变化率(AWCD)总体趋势都是逐渐增加,变化规律符合“S”型曲线,但对比CK组生防菌剂的添加提高了土壤微生物群落的AWCD值;在生态板上培养48 h时,B_(2)、B_(4)组的Shannon指数、Mclntosh指数和Simpson指数显著高于CK组(P<0.05);CK组与B_(2)、B_(4)组土壤微生物群落对碳源的利用方式存在差异,在主成分分析中起主要作用的是氨基酸类、胺类和酸类碳源。【结论】研究表明,添加链霉菌JD211有助于提高水稻土壤有机碳固存,优化稻田微生物群落碳代谢,使土壤微生物群落对碳源的利用更加均衡。对于微生物源农药调控微生物群落结构,明确其生态功能具有重要指导意义。

[Objective]Paddy soils are important arable soils.The excessive use of chemical fertilizers and fungicides has seriously damaged the ecological balance of rice soils in recent years.Due to the promotion and application of biological control,the problem has many solutions,in which plant endophytic bacteria with bacteriostatic potential have been widely used in soil disease control.Isolated from dove plants,Streptomyces JD211 is a potential biocontrol bacterium,and its effects on soil microbial community and carbon metabolism of rice were investigated to promote the study on the mechanism of microbial fertilizer.[Methods]In this study,Streptomyces JD211 was used as an exogenous applied microorganism,and rice soil without fungicide was used as a control,2%(B2)and 4%(B4)of the total soil weight of the fungicide were added as treatments,and the CO_(2)emission rate in the soil was measured by gas chromatography,the soil organic carbon content was measured by low-temperature external heat potassium dichromate oxidation-colorimetric method,and the soil microbial community metabolism was analyzed by Biolog-ECO method.[Results]The results showed that compared with the control group,the addition of different levels of biocides significantly increased the CO_(2)emission rate and organic carbon content of rice soil,and the soil organic carbon content of B2 and B4 treatment groups increased by 19.25%and 23.10%,respectively,the overall trend of the average color change rate(AWCD)of the three treatment groups all increased gradually,and the change pattern was consistent with the“S”curve,the addition of biocide in the CK group increased the AWCD value of soil microbial community in comparison;the Shannon index,Mclntosh index and Simpson index in B_(2) and B_(4) groups were significantly higher than those in the CK group when the groups were incubated on the ecological plate for 48 h(P<0.05);there were the differences between the CK group and B_(2) and B_(4) groups in the way of carbon source utilization by soil microbial communities,and the principal component analysis showed that the amino acid,amine and acid carbon sources played a main role.[Conclusion]The study showed that the addition of Streptomyces JD211 helped to improve organic carbon sequestration in rice soils,optimize carbon metabolism in paddy microbial communities,and make the utilization of carbon sources by soil microbial communities more balanced.It has important guiding significance for microbial source pesticides to regulate microbial community structure and clarify their ecological functions.