互花米草根系促生菌的筛选及其挥发性有机物质鉴定

Screening of growth-promoting rhizobacteria from Spartina alterniflora and identification of their volatile organic compounds

  • 摘要: 【目的】从互花米草根系菌当中筛选获得具有释放挥发性有机化合物(VOCs)促进植物生长能力的菌株,并对其释放的VOCs成分进行分析鉴定,为促进植物生长提供菌株资源和理论依据。【方法】以从互花评定米草根系中分离85株细菌为供试细菌,用二分隔培养皿与拟南芥共培筛选VOCs促生菌株,进一步评估多重促生功能,利用熵值法评定出最佳菌株;并通过形态学、生理生化、16S rRNA及gyrB基因分析定类;使用固相微萃取与气相色谱—质谱联用技术(GC-MS)鉴定该菌株VOCs成分。【结果】筛选出6株可通过释放VOCs促进拟南芥生长的细菌,即GXMZU2281、GXMZU2346、GXMZU2401、GXMZU3251、GXMZU3294、GXMZU4388。其中,GXMZU4388菌株具有溶磷、固氮、产铁载体、产吲哚乙酸(IAA)的促生活性,与对照组相比,在稀释20倍与100倍浓度菌液处理下,GXMZU4388菌株均能明显促进番茄生长,鲜重分别增加144.0%和186.2%,熵值法综合评定结果显示GXMZU4388菌株为最高分。GC-MS鉴定结果表明该菌株能产生9种VOCs成分,其中8种成分已被报道具有抑菌或促进植物生长的功能;6-甲基-2-庚酮、5-甲基-2-己酮、5-甲基-2-庚酮和3-甲基-2-戊酮的相对含量较高,占据主导地位。结合形态学观察、生理生化特性分析及16S rRNA和gyrB基因序列的分子生物学鉴定结果,确定GXMZU4388菌株为沙福芽孢杆菌(Bacillussafensis)。【结论】GXMZU4388菌株在促进植物生长各方面均表现优秀,在低浓度下也能显著发挥其促进植物生长的能力,能释放多种有利于植物生长与抑菌的VOCs,在菌肥开发上有极佳的应用潜力。

     

    Abstract: 【Objective】The strains with the ability to release volatile organic compounds(VOCs)to promote plant growth were screened from the rhizosphere bacteria of Spartina alterniflora,and the components of VOCs released were analyzed and identified to provide strain resources and theoretical basis for promoting plant growth.【Method】A total of 85 strains of bacteria were isolated from the rhizosphere soil of S. alterniflora as tested bacteria,and the VOCs growthpromoting strains were screened by co-culture with Arabidopsis thaliana in a two-partition culture dish. To further evaluate the multiple growth-promoting functions,the entropy method was used to select the best strain. It was classified by morphology,physiological and biochemical features,16S rRNA and gyrB gene analysis. Finally,the VOCs components of the strain were identified by solid-phase microextraction and gas chromatography-mass spectrometry(GC-MS).【Result】Six bacteria that could promote the growth of A. thaliana by releasing VOCs were screened:GXMZU2281GXMZU2346,GXMZU2401,GXMZU3251,GXMZU3294,GXMZU4388. Among them,GXMZU4388 strain had the ability of solubilizing phosphorus,nitrogen fixation,siderophore and heteroauxin(IAA)production. Compared with the control group,GXMZU4388 strain could greatly promote the growth of tomato under the treatment of 20 times and 100 times diluted bacterial solution,and the fresh weight increased by 144.0% and 186.2% respectively. The comprehensive evaluation scores of entropy method were the highest in GXMZU4388 strain. GC-MS was used to identify that the strain could produce 9 VOCs components,of which 8 components have been reported to have the function of inhibiting bacteria or promoting plant growth. The relative contents of 6-methyl-2-heptanone,5-methyl-2-hexanone,5-methyl-2-heptanone and 3-methyl-2-pentanone were relatively high,which occupied a dominant position. Combined with morphological observation,physiological and biochemical characteristics analysis and molecular biological identification of 16S rRNA and gyrB gene sequences,GXMZU4388 strain was identified as Bacillus safensis.【Conclusion】GXMZU4388 had excellent performance in promoting plant growth in all aspects. It can also significantly exert its ability to promote plant growth at low concentrations,and can release a variety of VOCs that are beneficial to plant growth and bacteriostasis. It has excellent application potential in the development of bacterial fertilizer.

     

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