泓森槐可培养内生固氮细菌多样性与潜在促生长特性评价

Evaluating diversity and potential growth promoting characteristics of the culturable endophytic diazotrophic bacteria isolated from Robinia pseudoacacia ‘Hongsen’

摘要:

【背景】泓森槐为豆科刺槐属的速生型落叶乔木，生长快，营养需求多。目前对于泓森槐内生固氮细菌的研究鲜有报道。【目的】研究泓森槐可培养内生固氮细菌的多样性及潜在促生长特性。【方法】从表面消毒的泓森槐根、茎、叶及根瘤中进行内生固氮细菌的分离纯化，采用IS-PCR指纹图谱技术将分离得到的菌株进行聚类，对各类群代表菌株进行16S rRNA基因系统发育分析、生理生化试验、固氮酶活性测定、促生长特性试验。【结果】从泓森槐中分离出56株细菌，聚为10个类群，分别为Paenibacillus sabinae、Klebsiella michiganensis、Kosakonia radicincitans、Kosakonia pseudosacchari、Mesorhizobium erdmanii、Mesorhizobium huakuii、Mesorhizobium silamurunense、Pseudomonas geniculata、Burkholderia territorii和Devosia riboflavina，其中5个类群为联合固氮菌、3个类群为共生固氮菌、2个类群为非固氮菌，表明泓森槐组织内生固氮细菌具有丰富的多样性。促生特性试验表明7个类群具溶磷能力、6个类群具解钾能力、6个类群具有产生长素能力、6个类群具产铁载体能力、2个类群具有产蛋白酶能力。【结论】泓森槐组织内生固氮细菌具有遗传多样性与促生长特性，其在农业微生物菌肥开发利用方面具有潜在价值。

Abstract:

[Background] Robinia pseudoacacia ‘Hongsen’ is a fast-growing deciduous tree of Robinia in Leguminosae. Endophytic diazotrophic bacteria of Robinia pseudoacacia ‘Hongsen’ is being researched little nowadays. [Objective] We studied the diversity and growth promoting characteristics of the culturable endophytic diazotrophic bacteria isolated from Robinia pseudoacacia ‘Hongsen’. [Methods] Strains were isolated and purified from surface sterilized roots, stems, leaves and root nodules of Robinia pseudoacacia ‘Hongsen’, the isolates were clustered by using IS-PCR finger-printing, nitrogenase activity of the representative strain of each group was measured, we also conducted phylogenetic analysis of 16S rRNA gene, physiological and biochemical tests and growth promoting experiments of the representative strains. [Results] A total of 56 strains were isolated from Robinia pseudoacacia ‘Hongsen’, belonging to ten groups: Paenibacillus sabinae, Klebsiella michiganens, Kosakonia radicincitans, Kosakonia pseudosacchari, Mesorhizobium erdmanii, Mesorhizobium huakuii, Mesorhizobium silamurunense, Pseudomonas geniculate, Burkholderia territorii and Devosia riboflavina, in which 5 groups were associative nitrogen-fixing bacteria, 3 groups were symbiotic nitrogen-fixing bacteria, 2 groups had not the nitrogen-fixing ability, which showed the rich diversity of endophytic diazotrophic bacteria of Robinia pseudoacacia ‘Hongsen’. Growth promoting experiments showed that 7 groups had the function of phosphorus solubility, 6 potassium solubility, 6 auxin secretion, 6 siderophore production, and 2 proteases production. [Conclusion] Endophytic diazotrophic bacteria isolated from Robinia pseudoacacia ‘Hongsen’ have abundant genetic diversity and growth promoting characteristics, which have potential value in exploitation and utilization of agricultural microbial fertilizer.