为挖掘烟草青枯病抑病型土壤有益微生物资源,通过大田试验分析了不同海拔高度抑病型和导病型土壤的微生物群落结构以及青枯菌、拮抗菌等的相对丰度.结果表明,与导病型土壤相比,烟草青枯病抑病型土壤中有益细菌门放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)、蓝藻门(Cyanobacteria)和有益真菌门接合菌门(Zygomycota)、壶菌门(Chytridiomycota)的相对丰度较高.在属水平上,抑病型土壤中一些有益微生物中慢生根瘤菌属(Mesorhizobium)、亚硝化螺菌属(Nitrosospira)等及拮抗微生物假单胞菌(Pseudomonas)、黄杆菌(Flavobacterium)、根瘤菌(Rhizobium)等细菌属和曲霉菌(Aspergillus)、木霉菌(Trichoderma)、漆斑菌(Myrothecium)等真菌属的相对丰度显著高于导病型土壤,其相对丰度与青枯病的发病率均存在显著负相关;而致病微生物劳尔氏菌属(Ralstonia)的相对丰度显著低于导病型土壤.因此,烟草青枯病抑病型土壤中含有丰富的拮抗微生物.

Bacterial wilt as a soil-borne disease was caused by Ralstonia solanacearum, and seriously damages the growth of tobacco. Integrated biocontrol method was explored to control bacterial wilt. Nevertheless, the long-term effects of the integrated biocontrol method on soil bacterial community, soil physicochemical properties and the incidence of bacterial wilt are not well understood. In this study, B. amyoliquefaciens ZM9, calcium cyanamide and rice bran were applied to tobacco fields in different ways. The disease index and incidence of tobacco bacterial wilt (TBW), soil physicochemical properties, colonization ability of B. amyoliquefaciens ZM9, and rhizopshere bacterial community were investigated. The results showed that the integrated application of B. amyoliquefaciens ZM9, rice bran and calcium cyanamide had the highest control efficiency of TBW and bacteria community diversity. Additionally, the integrated biocontrol method could improve the colonization ability of B. amyoliquefaciens ZM9. Furthermore, the integrated biocontrol method could effectively suppress TBW by regulating soil physicochemical properties, promoting beneficial bacteria and antagonistic bacteria of rhizopshere soil. This strategy has prospect of overcoming the defects in application of a single antagonistic bacteria and provides new insights to understand how to improve the colonization capacity of antagonistic bacteria and control efficacy for TBW.

Tobacco bacterial wilt (TBW) is seriously damages the growth of tobacco. There is an urgent need to find a safer and more effective measure to control TBW. In this study, B. amyloliquefaciens ZM9 and marigold powder were applied to the tobacco roots alone or in combination, and the potential inhibition of TBW was assessed. On the other hand, the effects of these treatments on soil physicochemical properties, rhizosphere microbial community and soil metabolites were also evaluated. The results showed that the application of B. amyloliquefaciens ZM9 or marigold powder alone significantly reduced the abundance of R. solanacearum in rhizosphere soil, while the integrated treatment showed the strongest inhibitory effect. Moreover, the integrated treatment can inhibit the secretion of chemoattractants, and affect the change of rhizosphere soil microbial composition. In conclusion, the combination of antagonistic bacteria agent B. amyloliquefaciens ZM9 with marigold powder can enhance the suppression of TBW. Furthermore, B. amyloliquefaciens ZM9 and marigold have synergistic effects on suppressing TBW by regulation soil physicochemical properties, soil metabolites and microbial structure. This study provide a promising strategy for TBW control by integrated applying of B. amyloliquefaciens ZM9 and marigold powder.

Biological control agents and soil amendments have been applied to control tobacco bacterial wilt, but the mechanism is not well-known. In the present study, a field experiment was performed to investigate the soil physicochemical properties, disease index (DI) and disease incidence of tobacco bacterial wilt, and rhizosphere microbial community. The results show that the control efficacy of single application of antagonistic bacteria and calcium cyanamide was 46.43% and 51.92%, respectively. While the combined control efficacy of antagonistic bacteria and calcium cyanamide was 65.79%. Besides, the combined application of antagonistic bacteria and calcium cyanamide could increase soil pH, total N alkaline N, and exchangeable Ca, which were negatively associated with the microbial diversity, soil-borne pathogenic microorganisms, and incidence of tobacco bacterial wilt. Additionally, the combination of antagonistic bacteria and calcium cyanamide can improve the proportion of some antagonistic microbial species, and these antagonistic microbial species were inversely associated with the DI of tobacco bacterial wilt. In conclusion: The integrated measure may influence soil microbial communities through enhancing soil physicochemical properties and rebuild healthy soil microbial community structure to mitigate tobacco bacterial wilt. The current study presented valuable insights into the mechanisms enhancing soil health in the integrated measure.

The role of hydrogen sulfide (H 2 S) in regulating the pathogenic bacteria has been well documented. However, whether exogenous H 2 S addition inhibits the pathogens in soil is not understood, and whether H 2 S can suppress the plant disease caused by pathogen R. Solanacearum is not clear. In the present study, different concentrations of H 2 S donor NaHS were applied to the tobacco field to explore the interrelation among NaHS, tobacco baterial wilt, soil physicochemical properties and microbial community. In order to decipher the disease suppression mechanism from the perspective of soil microecology. Application of NaHS significantly reduced the disease incidence and disease index of TBW, increased soil pH, alkali-hydrolyzed nitrogen (AN), available phosphorus (AP), available phosphorus (AP) and organic matter (OM). NaHS addition also changed soil microbial community composition and structure. Furthermore, NaHS addition significantly reduced the abundance of Ralstonia and Fusarium , and increas pathogenic ed beneficial microorganisms S olirubrobacter , Rhodococcus , Rhizobium , Pseudomonas , Paenibacillus , Microvirga , Lysobacter , Haliangium , Granulicella , Flavobacterium , Bacillus , Trichoderma and Aspergillus at the genus level. Our findings suggested that exogenous application of NaHS significantly suppressed TBW caused by R. Solanacearum through regulated soil microecology. This study revealed the potential of NaHS in control of bacterial wilt.

为有效防治烟草青枯病,采用细胞培养和毛细管法研究了烟草化感自毒物质邻苯二甲酸二丁酯对青枯菌的影响及趋化诱导效应,同时采用梯度训化法筛选邻苯二甲酸二丁酯降解菌,并通过盆栽试验测定了邻苯二甲酸二丁酯降解菌处理后的烟草青枯病发病率.结果表明,邻苯二甲酸二丁酯对青枯菌具有趋化诱导作用,并且在低浓度条件下能促进青枯菌生长;筛选的邻苯二甲酸二丁酯降解菌(Acinetobacter sp.Ed2)在土壤中对邻苯二甲酸二丁酯降解效率为51.17％;土壤中添加邻苯二甲酸二丁酯的处理(T1),与对照(CK)相比青枯菌数量显著提高59.89％;经邻苯二甲酸二丁酯降解菌Ed2处理(T2)后,与对照和T1处理相比,土壤中青枯菌数量分别降低84.63％和90.38％,青枯病发病率分别降低52.23％和136.42％.因此,利用邻苯二甲酸二丁酯降解菌消耗土壤中的邻苯二甲酸二丁酯,既减少青枯菌的营养供给,又截断邻苯二甲酸二丁酯对青枯菌的趋化诱导作用,从而显著降低了青枯病发病率.

将实验室保藏的青枯病拮抗菌ZM9和YH-22配制成复合菌剂,并将万寿菊提取物和复合菌剂联合配制成协同菌剂,通过分析万寿菊提取物对青枯菌的抑制效果,复合菌剂和协同菌剂抑制青枯菌的效果.结果表明,万寿菊提取物对青枯菌具有抑制作用,且万寿菊提取物用量与抑制效果呈显著负相关(Pearson=-0.997,P=0.047);万寿菊提取物对青枯病拮抗菌有一定的促进作用;复合菌剂和协同菌剂对青枯菌均有抑制作用,协同菌剂抑菌效果显著高于复合菌剂;综合分析表明万寿菊提取物可以与青枯病拮抗菌联合施用,并能增强对青枯菌病原菌抑制效果.研究结果为烟草青枯病生防菌剂的研制拓展了新的方向.

In order to improve the degradation efficiency of lignin and cellulose in tobacco straw and shorten the decomposing time of tobacco straw, the strains with the ability to degrade lignin and cellulose were screened out by plate screening and enzyme activity determination experiments. The effects of different strain combinations on tobacco straw degradation were discussed. The results showed that the obtained Lysinibacillus fusiformis (N019a), Trametes hirsuta (MA), and Rhizopus oryzae (imp) were effective in degrading lignin, hemicellulose, and cellulose in tobacco straw. The composite flora I composed of N019a, MA and imp was used for solid fermentation of tobacco stalk powder for 25 d. The degradation rates of hemicellulose, cellulose and lignin were 67.23±0.73%, 61.17±0.45% and 60.12±0.48%, respectively. B. tequilensis (B4), B. subtilis (B26) and A. niger (M90) composed a complex flora II with degradation rates of hemicellulose, cellulose and lignin being 72.15±0.35%, 65.68±0.55%, and 38.15±0.76%. The degradation rates of hemicellulose, cellulose and lignin by compound flora III composed of 6 strains was were 83.32±0.45%, 75.21±0.71% and 66.13±0.53%. Different degrading bacteria degrade different components in wood fiber with certain specificity, and the combination of multifunctional strains can significantly improve the biomass degradation effect of tobacco straw. The research results provide a basis for the development of a highly effective compound bacterial agent for tobacco straw degradation.