复合微生物菌肥对番茄青枯病发生和根际土壤细菌群落的影响

Effects of compound microbial fertilizer on the occurrence of tomato bacterial wilt and bacterial community of tomato rhizosphere soil

  • 摘要: 【目的】 探究复合微生物菌肥与番茄青枯病发生、根际土壤理化性质及土壤细菌群落之间的关系,为合理应用微生物菌肥绿色防控番茄青枯病提供理论依据。【方法】 以往年番茄青枯病严重发生地块为试验地,设清水对照(T1)、复合微生物菌肥(T2)、菌肥营养基质(T3)和复合微生物(T4)4个处理,测定番茄根际土壤养分含量、番茄植株生长、根系青枯病菌带菌率、青枯病发病率及根际土壤呼吸速率;采用16S rDNA测序技术分析施用复合微生物菌肥后番茄根际土壤细菌群落结构变化。【结果】 在番茄采收期测定结果显示,复合微生物菌肥和复合微生物处理的番茄根际土壤中有机质、铵态氮和速效磷含量均高于或显著(P<0.05)高于其他处理;与清水对照相比,复合微生物菌肥、复合微生物和菌肥营养基质处理的番茄株高、茎围、叶面积、光合作用、叶绿素相对含量(SPAD值)、产量和水溶性糖增幅分别为6.82%~27.88%、19.59%~47.40%、2.04%~17.08%、3.88%~11.21%、1.99%~17.15%、9.13%~22.37%和0.45%~5.12%;复合微生物菌肥处理的番茄根系青枯病菌带菌率降至11.11%,土壤呼吸速率较清水对照提高54.05%;与清水对照相比,复合微生物菌肥、复合微生物和菌肥营养基质处理的番茄根际土壤细菌属水平ACE指数和Chao1指数分别提高3.12%~6.64%和4.76%~7.18%,Simpson指数和Shannon指数无显著差异(P>0.05);复合微生物菌肥处理的芽孢杆菌目(Bacillales)和芽孢杆菌属(Bacillus)分别为排名前10的优势目(8.31%)和优势属(6.60%);4个处理中芽孢杆菌属与Christensenellaceae_R-7_group和WCHB1-32的丰度相似,与WCHB1-32、瘤胃梭菌属(Ruminiclostridium_1)、Christensenellaceae_R-7_group和噬几丁质菌科未培养菌属(uncultured_bacterium_f_Chitinophagaceae)正相关,与假单胞菌属(Pseudomonas)、厌氧绳菌科未培养菌属(uncultured_bacterium_f_Anaerolineaceae)和嗜甲基菌属(Methylophilus)负相关。复合微生物菌肥处理的代谢途径、次生代谢物生物合成、抗生素生物合成和氨基酸生物合成等功能微生物丰度增幅最明显;有机质、速效磷、速效钾、芽孢杆菌属、雷尔氏菌属(Ralstonia)和土壤呼吸速率与抗生素生物合成功能正相关,pH、芽孢杆菌属、雷尔氏菌属和土壤呼吸速率与氨基酸生物合成功能正相关,而盐度和发病率与2项功能负相关。【结论】 复合微生物菌肥能显著改良土壤养分比例、改善土壤细菌群落结构和功能特性、提升抗生素生物合成和氨基酸生物合成等功能、促进番茄生长、降低青枯病发病率。复合微生物菌肥500倍稀释液对番茄青枯病的防病促生作用显著,具有良好的应用前景。

     

    Abstract: 【Objective】 The purpose of the study was to explore the relationships between compound microbial fertilizer and the occurrence of tomato bacterial wilt,physicochemical properties of rhizosphere soil and soil bacterial communities,so as to provide theoretical basis for the the rational application of microbial fertilizer in green prevention and control of tomato bacterial wilt. 【Method】 Using plots with severe occurrence of tomato bacterial wilt in previous years as experimental plots,4 treatments were set up:clear water control(T1),compound microbial fertilizer(T2),bacterial fertilizer nutrient substrate(T3),compound microorganisms(T4). The nutrient content in tomato rhizosphere soil,the growth of tomato plant,the carrier rate of bacterial wilt pathogen in roots,incidence of bacterial wilt,and rhizosphere soil respiration rate were measured. Using 16S rDNA sequencing technology,the differences in the bacterial community structure of the tomato rhizosphere soil after the application of compound microbial fertilizer were investigated. 【Result】 Measurement results at the tomato harvest stage showed that,the contents of organic matter,ammonium nitrogen and available phosphorus in the rhizosphere soil of tomatoes treated with compound microbial fertilizer and compound micro-organisms were higher or significantly(P<0.05)higher than those in other treatments. Compared with the clear water control,the plant height,stem circumference,leaf area,photosynthesis,chlorophyll relative content(SPAD value),yield and water-soluble sugar content treated by compound microbial fertilizer,compound microorgani-sms and microbial fertilizer nutrient substrate all increased by 6.82%-27.88%,19.59%-47.40%,2.04%-17.08%,3.88%-11.21%,1.99%-17.15%, 9.13%-22.37% and 0.45%-5.12% respectively. The carrier rate of bacterial wilt pathogens in tomato roots decreased to 11.11% with compound microbial fertilizer treatment,and the soil respiration rate increased by 54.05% compared with the clear water control. Compared with the clear water control,the ACE index and Chao1 index at the bacterial genus level in the rhizosphere soil of tomatoes treated with compound microbial fertilizer,compound microorganisms,and microbial fertilizer nutrient substrate increased by 3.12%-6.64% and 4.76%-7.18% respectively,while there was no significant differences in Simpson index and Shannon index(P>0.05). For the compound microbial fertilizer treatment,Bacillales and Bacillus ranked among the top 10 dominant orders(8.31%)and genera(6.60%)respectively. Among the 4 treatments, the abundance of Bacillus was similar to that of Christensenellaceae_R-7_group and WCHB1 -32,and it was positively correlated with WCHB1-32,Ruminiclostridium_1,Christensenellaceae_R-7_group and uncultured_bacterium_f_Chitinophagaceae,and negatively correlated with Pseudomonas,uncultured_bacterium_f_Anaerolineaceae and Methylophilus. The compound microbial fertilizer treatment showed the most obvious increase in the abundance of functional microor‐ ganisms involved in metabolic pathways,biosynthesis of secondary metabolites,biosynthesis of antibiotic and biosynthesis of amino acid. Organic matter,available phosphorus,available potassium,BacillusRalstonia and soil respiration rate were positively correlated with function of biosynthesis of antibiotic. pH,BacillusRalstonia and soil respiration rate were positively correlated with function of biosynthesis of amino acid. Salinity and incidence were negatively correlated with the two functions. 【Conclusion】 Compound microbial fertili-zer can significantly improve soil nutrient ratios,modify the structure and functional characteristics of soil bacterial communities,enhance functions such as biosynthesis of antibiotic and biosynthesis of amino acid,promote the growth of tomato plant,and reduce the incidence of bacterial wilt. A 500-times dilution of compound microbial fertilizer exhibits remarkable disease prevention and growth-promoting effects on tomato bacterial wilt,indicating a promising application prospect.

     

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