| 摘要: |
| 【目的】从赤星病发病烟田的健康烟株根际土壤中分离筛选对烟草赤星病菌具有显著拮抗作用的菌株，并通过田间试验测定其对烟草赤星病的防效，以及其施后对烤烟品质的影响，为烟草赤星病的绿色防控提供参考。【方法】以赤星病发病烟田的健康烟株根际土壤为材料，采用稀释分离法和平板对峙法分离筛选对烟草赤星病菌具有显著抑制作用的拮抗细菌；通过生长速率法测定拮抗细菌对赤星病菌菌丝生长和形态的影响；采用形态学、生理生化特征和分子生物学方法对拮抗细菌进行鉴定；通过温室和田间试验评价其对烟草赤星病的防效，以及其施用后对烤烟品质的影响。【结果】从健康烟株根际土壤中分离的128株细菌中筛选获得1株对烟草赤星病菌具有良好拮抗作用的菌株Xh629A，通过16S rRNA-gyrA基因序列分析，结合形态学、生理生化特征将其鉴定为枯草芽孢杆菌(Bacillus subtilis)。其发酵滤液在体积分数1%，2%，10%比例混合下，对烟草赤星病菌菌丝抑制率分别可达72.98%，77.75%和92.30%。显微镜观察结果发现，拮抗细菌Xh629A能够引起烟草赤星病菌菌丝畸形，结节增多、断裂，原生质外渗。温室和田间试验结果表明，菌株Xh629A发酵液对烟草赤星病离体防效可达83.32%，田间防效为57.62%，明显优于化学药剂菌核净（43.79%）和多抗霉素（45.08%），同时显著提升烤烟品质。【结论】筛选获得1株对烟草赤星病菌具有显著拮抗作用的枯草芽孢杆菌(Bacillus subtilis)Xh629A，其在烟草赤星病生物防治中具有较大的应用潜力。 |
| 关键词: 烟草赤星病菌 枯草芽孢杆菌 生物防治 烟叶品质 防效 |
| DOI：10.13207/j.cnki.jnwafu.2025.02.010 |
| 分类号: |
| 基金项目:中国烟草总公司陕西省分公司科技项目(KJ-2021-02);中国烟草总公司重大科技项目(110202101056LS-16) |
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| Screening,identification and biocontrol effect of the antagonistic bacteria against tobacco brown spot |
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LI Xingshan1,2, WANG Nana1,2, CUI Chuanbin3, WANG Pingping3, YANG Mingming1,4, YAN Xia5,2, HUANG Lili1,4
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1.State Key Laboratory for Crop Stress Resistance and High-Efficiency Production,Yangling,Shaanxi 712100,China;2.College of Life Sciences,Northwest A&F University,Yangling,Shaanxi 712100,China;3.Shaanxi Branch of China National Tobacco Corporation,Xi’an,Shaanxi 710000,China;4.College of Plant Protection,Northwest A&F University,Yangling,Shaanxi 712100,China;5.State Key Laboratory for Crop Stress Resistance and HighEfficiency Production,Yangling,Shaanxi 712100,China
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| Abstract: |
| 【Objective】The aim was to isolate and screen the bacteria stains with significant antagonistic effect against tobacco brown spot caused by Alternaria alternata from the rhizosphere soil of healthy tobacco plants in the fields affected by brown spot disease.Field experiments were conducted to evaluate the biocontrol effect of antagonistic bacteria on tobacco brown spot disease,and their impacts on the quality of flue-cured tobacco after the application of antagonistic bacterial fermentation broth,aiming to contribute to the green prevention and control of tobacco brown spot disease.【Method】The rhizosphere soil of healthy tobacco plants which were planted in the field severely infected with brown spot disease was treated as the material.The bacterial strains were isolated from the rhizosphere soil by dilusion seperation method.The antagonistic activity of bacteria was tested by plate confrontation method.The effect of antagonistic bacteria on Alternaria alternata was tested through mycelial growth rate method and microscopic observation.The antagonistic bacteria was identified through morphological,physiological and biochemical characteristics,and molecular biological methods.The biocontrol effect of antagonistic bacteria on tobacco brown spot disease was evaluated through greenhouse and field experiments.The quality of tobacco was determined after the application of antagonistic bacterial fermentation broth.【Result】A strain Xh629A with good antagonistic effect on Alternaria alternata was screened from 128 strains of bacteria.The strain Xh629A was identified as Bacillus subtilis through the sequence analysis of 16S rRNA-gyrA genes,combined with its morphological,physiological and biochemical characteristics.When the fermentation filtrate was mixed at a ratios of 1%,2%,and 10%,the mycelial inhibition rates were 72.98%,77.75%,and 92.30%,respectively.The results of microscopy showed that the fermentation broth of strain Xh629A could cause deformities in the mycelium of Alternaria alternata,an increase and fracture of nodules,and the leakage of protoplasts.The results of field control efficacy test showed that the control effect could reach 83.32% in greenhouse experiment and the average control efficacy of the Xh629A fermentation broth on tobacco brown spot was 57.62%,which was better than that of the chemical fungicides dimethachlon (43.79%) and polyantimycin (45.08%).At the same time,the quality of flue-cured tobacco was significantly improved.【Conclusion】A Bacillus subtilis strain of Xh629A with significant antagonistic effect on Alternaria alternata was obtained by isolation and screening,which had great potential for application in the biological control of tobacco brown spot disease. |
| Key words: Alternaria alternata Bacillus subtilis biological control tobacco quality control effect |
