产铁载体细菌通过与病原菌竞争铁元素而具有良好的生防效果。本研究从人参根组织及根际土壤中分离细菌,对其抑菌作用和产铁载体能力进行筛选,并对所筛选的1株菌株进行发酵条件的单因素和响应面优化。结果表明,共分离得到细菌菌株207株,...产铁载体细菌通过与病原菌竞争铁元素而具有良好的生防效果。本研究从人参根组织及根际土壤中分离细菌,对其抑菌作用和产铁载体能力进行筛选,并对所筛选的1株菌株进行发酵条件的单因素和响应面优化。结果表明,共分离得到细菌菌株207株,其中8株菌株既具有产铁载体的能力又对人参黑斑、根腐和锈腐病菌具有良好抑制作用;经筛选发现菌株GR-39在限铁、富铁培养基上对黑斑病菌抑菌作用差异显著,并鉴定该菌株为普城沙雷氏菌Serratiaplymuthica。通过单因素试验确定菌株GR-39在蔗糖、蛋白胨5 g/L、温度34℃、p H 8时产铁载体相对含量为74.6%;通过响应面法建立了铁载体量与自变量的回归模型,得出最佳发酵条件为蔗糖6 g/L、蛋白胨5 g/L、p H 8时铁载体产量最大达77.13%。研究表明,菌株GR-39具有较强产铁载体能力并且对人参黑斑病菌防效显著,可为多功能微生物菌剂研制提供良好菌种资源。展开更多
为克服室内筛选生防菌的方法往往忽略植物基础作用的弊端,本文比较双重培养法、液体介质筛选法和种苗基质筛选法的优劣,并在改进种苗基质筛选法的基础上研制新装置。该装置由耐高温(135℃)、高压(0.15 MPa)的500 mL PP组培瓶改装而成。...为克服室内筛选生防菌的方法往往忽略植物基础作用的弊端,本文比较双重培养法、液体介质筛选法和种苗基质筛选法的优劣,并在改进种苗基质筛选法的基础上研制新装置。该装置由耐高温(135℃)、高压(0.15 MPa)的500 mL PP组培瓶改装而成。组培瓶的柱状空间分为植物种植区、植物病原菌培养区和候选生防菌培养区,各区间以0.45μm硝酸纤维滤膜隔阻。植物种植区敞口、植物病原菌培养区和候选生防菌培养区以盖子密闭。本文装置以近似自然条件的植物根系分泌物和土壤渗出物作为基质筛选候选生防菌,获得的结果更可信;以菌体密度的变化反映病原菌和候选生防菌的拮抗效果,容易检测。该装置构造简单、成本低廉、使用方便,可用于各种植物根部病原菌生防菌的批量筛选,但不适用于植物叶片、茎秆病害的生防菌筛选。展开更多
目的:为更有效防治棉花枯萎病和研制新型生物农药提供技术依据,本研究探究生防菌代谢产物与化学杀菌剂对棉花枯萎病菌(Fusarium oxysporum f. sp.vasinfectum)的抑制活性。方法:采用对峙培养法、菌丝生长速率法测定生防菌、发酵上清液...目的:为更有效防治棉花枯萎病和研制新型生物农药提供技术依据,本研究探究生防菌代谢产物与化学杀菌剂对棉花枯萎病菌(Fusarium oxysporum f. sp.vasinfectum)的抑制活性。方法:采用对峙培养法、菌丝生长速率法测定生防菌、发酵上清液、脂肽粗提物以及化学杀菌剂对棉花枯萎病菌的抑制特性。结果:对峙培养法得出生防菌SJ06对棉花枯萎病菌的抑制率为78.24%。发酵上清液的浓度从6.25μL/mL增至100.00μL/mL对病菌的抑制率从46.90%增至80.30%,其对病菌的EC50为7.37μL/mL;脂肽粗提物的质量浓度从673.96μg/mL增至8 120.00μg/mL对病菌的抑制率从19.90%增至77.30%,对病菌的EC50为2 720.20μg/mL。棉花枯萎病菌对多菌灵、戊唑醇的敏感性较高,戊唑醇和多菌灵对病菌的EC50分别为0.34、0.49μg/mL;其次分别为腈菌唑、苯醚甲环唑和丙环唑,其对病菌的EC50分别为1.07、1.34、1.54μg/mL,而丙森锌对病菌的抑制活性较差,EC50为63.25μg/mL。结论:解淀粉芽孢杆菌发酵代谢物和戊唑醇等麦角甾醇生物合成抑制剂对棉花枯萎病菌具有较好的抑制活性。展开更多
The study was taken up with the objective of testing whether the endophytic organisms isolated from crops that are normally non-hosts to the bacterial wilt pathogen Ralstonia solanacearum possessed pathogen-antagonist...The study was taken up with the objective of testing whether the endophytic organisms isolated from crops that are normally non-hosts to the bacterial wilt pathogen Ralstonia solanacearum possessed pathogen-antagonistic activity and to evaluate the selected isolates for the alleviation of wilt disease in the target tomato crop through horizontal movement of promising organisms. Sixteen endophytic bacteria (EB) isolated from the micropropagated cultures of grape, watermelon and papaya were tested for potential antagonistic effects against R. solanacearum tomato isolate “NH-01” through agar-well diffusion assay. Enterobacter cloacae from papaya (EB-11) displayed the maximum antagonistic effect followed by Bacillus subtilis (EB-06) and B. flexus (EB-07) from watermelon and B. pumilus (EB-02) from grape. Testing the above organisms for crop protection through seed fortification of susceptible tomato cv. Arka Vikas at sowing in R. solanacearum inoculated (Ral+) organic cocopeat showed EB-02 and EB-11 promising (33% and 32% survival, respectively, four weeks after sowing against 15% in Ral+ control). A second trial showed 37%, 28%, 21% and 55% seedling survival 6 weeks after sowing for EB-02, EB-06, EB-07 and EB-11 respectively, compared to 2.5% in non-treated control. Assessing the four endophytes for crop protection in Ral+ sick-soil through seedling fortification at transplanting indicated less disease incidence in treated sets (40%, 40%, 20% and 20% survival, respectively, six weeks after transplanting) over non-fortified control (5%). Endophytic fortification of seedlings through hypocotyl inoculation showed some systemic resistance induction upon seedling transplanting to sick soil but not with petiole fortification. Seedling growth was enhanced by the isolates EB-06 and EB-07. The study thus identifies four endophytic organisms from crops unrelated to tomato possessing potential antagonistic activity against the wilt pathogen and prospects for exploitation as biocontrol agents coupled with seedling growth promotion effects.展开更多
Silicate solubilizing bacteria (SSB) can play an efficient role in soil by solubilizing insoluble forms of silicates. In addition to this some SSB can also solubilize potassium and phosphates, hence increasing soil fe...Silicate solubilizing bacteria (SSB) can play an efficient role in soil by solubilizing insoluble forms of silicates. In addition to this some SSB can also solubilize potassium and phosphates, hence increasing soil fertility and enhancing plant defense mechanisms. A total of 111 bacterial strains were isolated from various habitats of Pakistan and screened for solubilization of silicate, phosphate and potassium on respective media. Out of these, 35 bacterial isolates were capable of solubilizing either silicate, phosphate or potassium. Amongst these 7 bacterial isolates were capable of solubilizing all three minerals tested. The highest silicate (zone diameter 54 mm) and phosphate solubilization (zone diameter 55 mm) was observed for bacterial isolate NR-2 while the highest potassium solubilization was observed for NE-4b (zone diameter 11 mm). Dual culture antagonistic assays were carried out by using these bacterial isolates against four plant pathogenic fungi Magnaporthae grisae, Rhizoctonia solani, Altarnaria alternata and Macrophomina pheasolina. Mean zone of inhibition of these bacterial isolates against the four pathogenic fungi ranged between 4 mm to 39 mm. The largest zone of inhibition against all four bacterial strains was recorded for bacterial isolate NR-2 followed by NE-4b. These strains will be further investigated for their plant growth promoting activities in the future.展开更多
文摘产铁载体细菌通过与病原菌竞争铁元素而具有良好的生防效果。本研究从人参根组织及根际土壤中分离细菌,对其抑菌作用和产铁载体能力进行筛选,并对所筛选的1株菌株进行发酵条件的单因素和响应面优化。结果表明,共分离得到细菌菌株207株,其中8株菌株既具有产铁载体的能力又对人参黑斑、根腐和锈腐病菌具有良好抑制作用;经筛选发现菌株GR-39在限铁、富铁培养基上对黑斑病菌抑菌作用差异显著,并鉴定该菌株为普城沙雷氏菌Serratiaplymuthica。通过单因素试验确定菌株GR-39在蔗糖、蛋白胨5 g/L、温度34℃、p H 8时产铁载体相对含量为74.6%;通过响应面法建立了铁载体量与自变量的回归模型,得出最佳发酵条件为蔗糖6 g/L、蛋白胨5 g/L、p H 8时铁载体产量最大达77.13%。研究表明,菌株GR-39具有较强产铁载体能力并且对人参黑斑病菌防效显著,可为多功能微生物菌剂研制提供良好菌种资源。
文摘为克服室内筛选生防菌的方法往往忽略植物基础作用的弊端,本文比较双重培养法、液体介质筛选法和种苗基质筛选法的优劣,并在改进种苗基质筛选法的基础上研制新装置。该装置由耐高温(135℃)、高压(0.15 MPa)的500 mL PP组培瓶改装而成。组培瓶的柱状空间分为植物种植区、植物病原菌培养区和候选生防菌培养区,各区间以0.45μm硝酸纤维滤膜隔阻。植物种植区敞口、植物病原菌培养区和候选生防菌培养区以盖子密闭。本文装置以近似自然条件的植物根系分泌物和土壤渗出物作为基质筛选候选生防菌,获得的结果更可信;以菌体密度的变化反映病原菌和候选生防菌的拮抗效果,容易检测。该装置构造简单、成本低廉、使用方便,可用于各种植物根部病原菌生防菌的批量筛选,但不适用于植物叶片、茎秆病害的生防菌筛选。
文摘The study was taken up with the objective of testing whether the endophytic organisms isolated from crops that are normally non-hosts to the bacterial wilt pathogen Ralstonia solanacearum possessed pathogen-antagonistic activity and to evaluate the selected isolates for the alleviation of wilt disease in the target tomato crop through horizontal movement of promising organisms. Sixteen endophytic bacteria (EB) isolated from the micropropagated cultures of grape, watermelon and papaya were tested for potential antagonistic effects against R. solanacearum tomato isolate “NH-01” through agar-well diffusion assay. Enterobacter cloacae from papaya (EB-11) displayed the maximum antagonistic effect followed by Bacillus subtilis (EB-06) and B. flexus (EB-07) from watermelon and B. pumilus (EB-02) from grape. Testing the above organisms for crop protection through seed fortification of susceptible tomato cv. Arka Vikas at sowing in R. solanacearum inoculated (Ral+) organic cocopeat showed EB-02 and EB-11 promising (33% and 32% survival, respectively, four weeks after sowing against 15% in Ral+ control). A second trial showed 37%, 28%, 21% and 55% seedling survival 6 weeks after sowing for EB-02, EB-06, EB-07 and EB-11 respectively, compared to 2.5% in non-treated control. Assessing the four endophytes for crop protection in Ral+ sick-soil through seedling fortification at transplanting indicated less disease incidence in treated sets (40%, 40%, 20% and 20% survival, respectively, six weeks after transplanting) over non-fortified control (5%). Endophytic fortification of seedlings through hypocotyl inoculation showed some systemic resistance induction upon seedling transplanting to sick soil but not with petiole fortification. Seedling growth was enhanced by the isolates EB-06 and EB-07. The study thus identifies four endophytic organisms from crops unrelated to tomato possessing potential antagonistic activity against the wilt pathogen and prospects for exploitation as biocontrol agents coupled with seedling growth promotion effects.
文摘Silicate solubilizing bacteria (SSB) can play an efficient role in soil by solubilizing insoluble forms of silicates. In addition to this some SSB can also solubilize potassium and phosphates, hence increasing soil fertility and enhancing plant defense mechanisms. A total of 111 bacterial strains were isolated from various habitats of Pakistan and screened for solubilization of silicate, phosphate and potassium on respective media. Out of these, 35 bacterial isolates were capable of solubilizing either silicate, phosphate or potassium. Amongst these 7 bacterial isolates were capable of solubilizing all three minerals tested. The highest silicate (zone diameter 54 mm) and phosphate solubilization (zone diameter 55 mm) was observed for bacterial isolate NR-2 while the highest potassium solubilization was observed for NE-4b (zone diameter 11 mm). Dual culture antagonistic assays were carried out by using these bacterial isolates against four plant pathogenic fungi Magnaporthae grisae, Rhizoctonia solani, Altarnaria alternata and Macrophomina pheasolina. Mean zone of inhibition of these bacterial isolates against the four pathogenic fungi ranged between 4 mm to 39 mm. The largest zone of inhibition against all four bacterial strains was recorded for bacterial isolate NR-2 followed by NE-4b. These strains will be further investigated for their plant growth promoting activities in the future.
