生防菌剂对西瓜根际土壤微生物群落和 尖抱镰刀菌属的影响. (Chinese)

【Objective】 This study investigated the effects of different biocontrol agents on microbial community structure and Fusarium oxysporum f. sp. to provide basis for understanding the inhibition of watermelon Fusarium wilt by biocontrol agents.【Method】 Watermelon seedlings were transplanted into the watermelon soil with continuous cropping for 20 years, and they were divided into four treatments of roots injection with 1 mL bio control agents of Bacillus am yloliquefaciens B6 (B6), Pseudomonas brassi-cacearum WF19 (WF1 9), B6 and WF1 9 compound bacterial solutions (bacterial content of each bacterial solution was 1 X 10s CFU/mL, BW) and sterile water (control). After watermelon harvest, rhizosphere soil was collected, and soil pH, contents of organic matter (OM) total nitrogen (TN), nitrate nitrogen (NOT-N), ammonium nitrogen (NH.-N), total phosphorus (TP), available phosphorus (AP), total potassium (TK) and available potassium (AK) and activities of catalase (CAT) alkaline phosphatase (ALP), urease (URE) and sucrase (SUC) were measured. The changes of microbial communities in the rhizosphere soil of watermelon were analyzed by high-throughput sequencing (Illumina Hiseq) technology. The effects of soil physical and chemical factors, enzyme activities and microbial functions on Fusarium were evaluated based on path analysis and SEM structural equation.【Result】 Biocontrol agent B6 increased the activities of four soil enzymes and the contents of TN, AP, N()r~N, NH"-N and ()M, but decreased the contents of AK and TK. WF1 9 increased CAT. ALP and SIJC activities, decreased URE activity and TN content, and increased TI\AI\TK, AK, N()r-N, NH-N and OM contents in soil. BW increased soil N()「N content and CAT and SUC activities while decreased URE and ALP activities and soil TN, TI\TK, AI\AK, N()s ~-N and OM contents. After biocontrol agents application, the relative abundance of Fusarium oxysporum f. sp. decreased in WF1 9 and BW treatments, and that of Gibberella decreased in B6 treatments. AP and TP contents and URE activity had the greatest correlation with bacterial community structure, while AP and TK contents and URE activity had the greatest correlation with fungal community structure. Nitrate respiration (一2. 27), nitrogen fixation (一1.55) and nitrite ammonization (一0, 57) had negative effects on Fusarium oxysporum f. sp.【Conclusion】 Bio control agents affected the nutrient cycle of the ecosystem by regulating soil nutrient content and soil enzyme activity, impacted soil microbial community structure and functional diversity, and reduced relative abundance of phypathogen, so as to inhibit fusarium wilt. [ABSTRACT FROM AUTHOR]

］【目的】了解不同生防菌剂对西瓜根际微生物群落结构和尖翘镰刀菌(Fusarium oysporum f. sp.) 的影响, 为生防菌剂抑制西瓜枯萎病的机理研究提供依据"【方法】将西瓜苗移栽到连作20年西瓜的土壤中, 设置 B(kWF19,BW和对照4个处理, 分别根部注施生防菌剂解淀粉芽泡杆菌B6、油菜假单胞菌WF19.B6和WF19复合 菌液(各菌液细菌含量均为1X10* CFU/'mL)及无菌水1 ml*株,在西瓜采摘后采集根际土壤, 测定土壤pH、有机质 (021)、全氮(TN)、硝态氮(NO; N)、钱态氮(NHj N)、全磷(TP)、有效磷(AP),全钾(TK)、速效钾(AK)含量及过氧 化氢酶(CAT)、碱性磷酸酶(ALP).K酶(URE)、蔗糖酶(SUC)活性, 并利用高通量测序(Illumina Hiscq)技术分析西 瓜根际土壤的微生物群落变化"采用路径分析和SEM结构方程评估土壤环境因子、生物酶活性和微生物功能对尖 翘镰刀菌的影响"【结果】生防菌剂提高了土壤4种生物酶活性和TN/n\AI\NO7 N、NHj N.OM含量, 降低 了 AK和TK含量;WF19提高了土壤CAT.ALP和SUC活性, 降低了 URE活性和TN含量, 增加了土壤TI\AI\TK.AK.NO; N、NH［ N和()IM含量;提升了土壤NO; N含量J'AT和SUC活性, 降低了 URE和AU＞活性, 减少了土壤中TN/n\TK,Ai\AK,NO; N和含量"根部注施生防菌剂后,WF19和BW处理土壤中尖翘镰刀 菌的相对丰度降低,B6处理土壤中赤霉菌属的相对丰度降低" AP、TI＞含量和URE活性与细菌群落结构的关联性最 大,AI\TK含量和URE活性与真菌群落结构的关联性最大;硝酸盐呼吸、固氮和亚硝酸盐氨化对尖抱镰刀菌具有负效 应, 效应系数分别为一2. 27,-1.55和一0.57.【结论】生防菌剂通过调节土壤养分含量和生物酶活性影响生态系统的 养分循环, 逬而影响土壤微生物群落结构和功能多样性, 降低病原菌的相对丰度, 从而发挥防治枯萎病害的作用. [ABSTRACT FROM AUTHOR]

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