耐低温荧光假单胞菌筛选体系建立及其植物促生作用评价

Construction of screening system for cold tolerant Pseudomonas fluorescens for plant growth-promotion

【目的】以前期研究小麦生境分离细菌为菌株库,从中筛选耐低温菌株,评价其植物促生效果。【方法】通过4°C低温培养筛选耐低温菌株。以产吲哚乙酸、1-氨基环丙烷羧酸(ACC)脱氨酶、嗜铁素以及无机、有机磷溶解能力为评价指标,测定15°C和28°C环境中耐低温菌株的植物促生作用潜力,利用赋分评估系统选定潜力菌株进行温室和田间试验验证其植物促生作用。【结果】筛选到34株耐低温菌株,从中选定的8株植物促生潜力细菌温室试验促生效果和评估分值之间的相关性在0.62以上,菌株1b YB22和3b JN2在28°C环境中对黄瓜的促生效果均在28%以上,二者在15°C环境中对青菜种子根长的促生效果分别为116.76%和46.82%,菌株1b YB22在15°C环境中对青菜的促生效果为25.11%。菌株1b YB22在田间应用对小麦生长同样具有促生作用,增产效果达0.58%。【结论】研究建立的筛选体系从小麦生境分离菌株中获得了耐低温荧光假单胞菌株1b YB22和3b JN2,两株细菌在15°C和28°C均具有植物促生作用,同时可以在田间促进小麦生长。

[Objective] We previously isolated bacterial strains from winter wheat habitats, now, we will screen cold tolerant strains from those isolates and assess their plant growth-promoting potential. [Methods] We screened cold tolerant strains on nutrient agar plates incubated at 4℃, determined these cold tolerant strains＇ plant growth-promoting attributes such as indole-3-acetic acid （IAA） production, 1-aminocyclopropane-1-carboxylate （ACC） deaminase production, inorganic and organic phosphate solubilization and siderophores production, selected strains with good potential according to the assessment system established here, and then tested their plant biomass increase effects at different temperatures based on bioassay experiments. [Results] We screened 34 cold tolerant strains from those isolates. For the selected 8 strains with good potential, the correlation coefficiency indicating coincident relationship between the assessed growth promoting potential and the increase effect on plants in greenhouse condition was more than 0.62. Among them, lbYB22 and 3bJN2 exhibited more than 28% increase effect on shoot weights of cucumber incubated at 28℃, and seed bacterization with lbYB22 and 3bJN2 also increased non-heading Chinese cabbage＇s root lengths with 116.76% and 46.82% at 15℃, respectively. And lbYB22 exhibited 25.11% increase effect on shoot weights of non-heading Chinese cabbage incubated at 15 ℃. Field testing of the lbYB22 inoculum in wheat also showed significant increase in growth and yield. [Conclusion] Through the screening system established in this study, we obtained cold tolerant P. fluorescens strains lbYB22 and 3b J-N2 from wheat habitat isolates, and these two bacterial strains both exhibited plant growth-promoting effect at 15 ℃ and 28 ℃ and promoted the growth of wheat in the field.