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| 魔芋内生细菌DS4的鉴定及其生防促生特性研究 |
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段杉1,2, 李奕斐1,2, 刘晨钰1,2, 王郑琪1,2, 张亚丽1,2, 赵靖靖1,2, SHAH Faisal3, 何斐1,2
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1.富硒魔芋陕西省高校工程研究中心，陕西 安康 725000;2.安康学院 现代农业与生物科技学院，陕西 安康 725000;3.白沙瓦农业大学 农学系，开伯尔-普赫图赫瓦省白沙瓦 23060，巴基斯坦
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| 摘要: |
| 【 目的】分离筛选具有生防促生潜力的花魔芋内生细菌，为魔芋土传病害的防治提供菌种资源。【 方 法】采用纯培养法从健康魔芋球茎中分离内生细菌，用滤纸片扩散法和平板对峙法分别检测分离菌株DS4对病原细 菌和病原真菌的拮抗能力；采用硫酸铵沉淀、盐酸沉淀甲醇抽提和乙酸乙酯萃取法提取内生细菌DS4中的抑菌活性物 质，用比浊法测定内生细菌的抑菌活性；并采用平板法检测菌株产酶、溶解磷酸盐和固氮能力，比色法检测菌株产IAA能力；通过形态特征和16S rDNA序列分析鉴定菌株DS4的分类地位，用盆栽试验检测该菌株对魔芋生长的影响及其 对魔芋土传病害的生防潜力。【 结果】从健康魔芋植株分离获得16株内生细菌，采用平板对峙法从分离的内生细菌中筛选出1株对魔芋白绢病、干腐病和软腐病病原菌有明显抑制作用的内生细菌DS4，该菌株被鉴定为反硝化无色杆菌 （Achromobacter denitrificans）。DS4对齐整小核菌（Sclerotium rolfsii）和尖孢镰孢菌（Fusarium oxysporum）菌丝生长 的抑制率分别达81.3%和61.9%。硫酸铵沉淀、盐酸沉淀甲醇抽提和乙酸乙酯萃取法提取的内生细菌DS4抑菌物质对7种魔芋软腐病菌均有抑制作用，其中盐酸沉淀甲醇抽提的提取效果最好，病原菌接种培养12，24和48 h，其提取物对7种软腐病原菌的抑菌率分别为81.3%-94.4%，88.6%-97.2%和88.3%-98.1%。该菌具有产IAA、蛋白酶、 淀粉水解酶、纤维素酶、溶解磷酸盐和固氮的能力。在盆栽条件下，先接种DS4再接种病原菌处理对魔芋软腐病有一定的防效，其在接种病原菌后10和20 d以及收获期的发病率均为20%，防效分别为33.3%，33.3%和50.0%，同时显著提高了魔芋球茎鲜质量、根茎鲜质量和根茎数量。【 结论】花魔芋内生细菌DS4兼具防病和促生能力，具有开发为 促进魔芋生长和防治魔芋土传病害生物菌肥的潜力。 |
| 关键词: 魔芋 内生细菌 抑菌作用 魔芋软腐病 促生作用 |
| DOI：10. 13207/j. jnwafu. 2026. 08. 014 |
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| 基金项目:陕西省科技厅项目（2025-JC-QN-1597，2025NC-YBXM-378）；陕西省教育厅项目（24JR002）；国家级大学生创新创业训练计 划项目（202311397029） |
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| Identification and characterization of biocontrol and plant growth⁃promoting traits of endophytic bacteria strain DS4 isolated from Amorphophallus konjac |
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DUAN Shan1,2, LI Yifei1,2, LIU Chenyu1,2, WANG Zhengqi1,2, ZHANG Yali1,2, ZHAO Jingjing1,2, SHAH Faisal3, HE Fei1,2
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1.Engineering Research Center of Selenium-rich Konjac，Universities of Shaanxi Province，Ankang，Shaanxi 725000，China;2.School of Modern Agriculture & Biotechnology，Ankang University，Ankang，Shaanxi 725000，China;3.Department of Agronomy，The University of Agriculture Peshawar，Khyber Pakhtunkhwa 23060，Pakistan
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| Abstract: |
| 【 Objective】The study aims to isolate and screen endophytic bacteria from konjac（Amorphophallus konjac） with biocontrol and plant growth-promoting potential，to provide strain resources for the prevention and control of soil-borne diseases of konjac.【Method】Endophytic bacteria were isolated from healthy konjac corms using pure culture techniques. Antagonistic activity of strain DS4 against pathogenic bacteria and fungi was assessed via the agar diffusion and dual-culture confrontation assays，respectively. Bioactive antimicrobial compounds produced by strain DS4 were extracted through ammonium sulfate precipitation，acid precipitation followed by methanol extraction，and ethyl acetate extraction. The antimicrobial activity was quantified by turbi-dimetric assays. Enzymatic activities，phosphate solubilization，nitrogen fixation，and indole-3-acetic acid（IAA） production were evaluated using plate assays and colorimetric methods. Strain DS4 was taxonomically classified based on morphological characteristics and 16S rDNA sequencing. A pot experiment was carried out to detect the effects of this strain on the growth of konjac and its biocontrol potential.【Result】Sixteen endophytic bacte- rial isolates were obtained from healthy konjac tissues. Using the plate confrontation method，one endophytic bacterial strain DS4 was selected from the isolates for its significant antagonism against the pathogens causing kon-jac southern blight，dry rot，and soft rot. Strain DS4 was identified as Achromobacter denitrificans.The inhibition rates of strain DS4 against the mycelial growth of Sclerotium rolfsii and Fusarium oxysporum reached 81.3% and 61.9%，respectively. Extracts from DS4 demonstrated broad-spectrum antimicrobial activity against seven konjac soft rot pathogens. The highest efficacy was observed in the acid precipitation-methanol extract，showing inhibition rates of 81.3%-94.4%，88.6%-97.2%，and 88.3%-98.1% at 12，24，and 48 h postinoculation，respectively. The strain exhibited multiple plant growth-promoting traits，including IAA synthesis，the production of protease，amylase，and cellulase，phosphate solubilization，and nitrogen fixation. In greenhouse trials，pre-inoculation with DS4 reduced soft rot incidence to 20% at 10 and 20 d post-inoculation and at harvest，corresponding to control efficacies of 33.3%，33.3% and 50. 0%. Additionally，significant improvements were observed in tuber fresh weight，rhizome quality，and rhizome biomass.【Conclusion】Strain DS4 demonstrates both biocontrol activity and plant growth-promoting capabilities，indicating its potential application as a biofertilizer and biocontrol agent in konjac cultivation to mitigate soil-borne diseases. |
| Key words: Amorphophallus konjac endophytic bacteria antibacterial effect Amorphophallus konjac soft rot disease growth-promoting effect |
