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摘要：番茄青枯病是青枯菌引起的一种细菌性文管束疾病，利用化学农药确实可以暂时的控制病害，但由于青枯菌分布广泛，寄主范围广，变异性强且易进化，一方面过量的化学药品本就会导致病原微生物产生抗性，另一方面结合青枯菌的特点，国内外也开始利用生态学的原理，从进化的角度来研究生物防治措施对抑制病原菌入侵的作用。本课题设计了解淀粉芽孢杆菌T-5和青枯菌专性噬菌体PQL-14单独或配合抑制青枯菌的入侵的实验，我们发现青枯菌能够快速进化对抗单一的生防细菌或噬菌体，单一的防控措施很难有效的控制青枯病，对二者复配的研究，理论上可以大大提高抑菌效率，原理在于生防菌通过生态位竞争、营养竞争以及产生拮抗物质，形成第一道防线对抗病原菌，然后噬菌体侵染并裂解青枯菌，青枯菌因此承受了最大的生存成本。从应用角度来看，通过构建多营养级区系，从根际微生物入手实现长期的生物防治，符合环境友好的理念宗旨。28134
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毕业论文关键词：青枯菌；生防措施；适应性
Synergetic mechanism of competitive bacterium and parastical bacteriophage on the control of Ralstonia solanacearum in tomato
Abstract： The bacterial wilt of tomato is one kind of bacterial vasculopathy caused by Ralstonia solanacearum and we can control the disease temporarily with pesticides. However, because RS is widely distributed with a large range of hosts, also it has strong variability and easy to evolution , the use of pesticides has led to the emergence of resistant microbial pathogens--Thus the world begin to use ecological and evolutionary framework to study the effects of microbial biocontrol measures against Ralstonia solanacearum bacterial pathogen. The study designs single and combinatory treatment of Bacillus amyloliquefaciens and R. solanacearum specific bacteriophage on control the bacterial wilt. We find the RS can rapidly evolve against a single biocontrol bacterium or phage, in other words, a single control measure is difficult to control the bacterial wilt effectively. On the contrary, when both of them are applied,the antibacterial efficiency can be greatly improved. The principle is that biocontrol forms the first line to defense against pathogens through niche competition, nutrition competition and producing antibiotics.Then the phage infects and cracks the Ralstonia solanacearum. Crucially, pathogen suffered relatively the highest fitness cost of adaptation in combinatory treatment. From a more applied perspective, one way to achieve long-term biological control is to take advantage of coexisting host-associated rhizosphere microbiota and construct a multi-trophic level flora, also it is in line with environmental friendly purpose.
Key words: Ralstonia solanacearum, biocontrol agents, adaptation
目 录
摘要1
关键词1
Abstract1
Key words1
1 背景1
2 材料与方法2
2.1 供试菌株及培养 2
2.1.1 强致病力青枯菌QL-Rs11152
2.1.2 生防菌解淀粉芽孢杆菌T-52
2.1.3 青枯菌特异性噬菌体PQL-142
2.2 试验设计 2
2.3 检测方法2
3 结果3
3.1 抑制青枯菌入侵的室内试验3
3.2 进化后的病原菌对噬菌体的适应性3
3.3 进化后的病原菌对生防菌拮抗物质的适应性4
3.4 生防措施组合后对发病率的影响4
4 讨论5
致谢6
参考文献6
噬菌体协同生防细菌抑制番茄青枯病的效果研究
1 背景
青枯病菌是一种毁灭性的土传病菌，可侵染的范围涉及到50 多个科的 200 余种植物【1】，番茄就在其中，该病原菌从寄主植物的根部，入侵木质部导管，通过文管束系统迅速扩张到植物的地上部分，病菌的大量定殖引起导管功能丧失，进而引发植物萎蔫，受害植株的茎基部和根文管束有褪色现象，并最终导致植物死亡【2】。青枯病的防治很有困难，作物一旦感病，将会造成大量减产【3】，因此番茄青枯病也严重制约着番茄产业的发展以及经济效益的提高。常用防治番茄青枯病的策略有化学农药、土壤改良、抗病品种、嫁接与轮作等，但效果均不稳定，这使我们认识到盲目的投入新的防控措施并不能有效的抑制病原菌的入侵，因为青枯菌很容易变异并发生进化致使原有策略的失效。