促生潜力玉米种子内生细菌分离鉴定及发酵条件优化

Endophytic Bacteria from Maize Seed with Growth-promoting Potential:Isolation,Identification and Optimization of Fermentation Conditions

旨在从玉米种子中分离鉴定具有促生功能的内生细菌,为菌肥研发提供菌种资源和技术支持。以玉米种子为试材,用平板涂布和三区划线法分离、纯化获得玉米种子内生菌,滴灌试验筛选促生菌株,采用单因素和正交试验优化发酵条件,通过盆栽滴灌试验验证菌株的促生效应。试验分离获得一株促生效果相对较强的菌株,编号为SYL4,初步鉴定为枯草芽孢杆菌(Bacillus subtilis)。SYL4最佳培养条件:蛋白胨1.5%,玉米粉0.5%,CaCO30.25%,接种量5%,转速200 r/min,温度34℃,培养时间48 h。滴灌优化发酵液使得玉米幼苗根长、叶长分别增加12.86%、9.4%,根重、叶重分别增加6.52%、6%。本研究分离获得一株具促生潜力的内生菌SYL4,优化后的发酵条件提高玉米幼苗过氧化物酶(POD)活性,有效促进玉米幼苗生长。

The aim of this study is to isolate and identify endophytic bacteria with growth-promoting function from maize seeds,and to provide strain resources and technical support for the research and development of bacterial fertilizer.In this experiment,maize seeds were used as the test materials,and endophytic bacteria were isolated and purified by plate coating and three-zone marking method.Drip irrigation test was used to screen growth-promoting strains.The fermentation conditions were optimized by single factor test and orthogonal test.The promoting effect of the strains was verified by pot drip irrigation test.Bacillus subtilis was isolated and identified as SYL4,which had a relatively strong growth-promoting effect.The optimal culture condition for SYL4 was:peptone 1.5%,corn flour 0.5%,CaCO30.25%,inoculation volume 5%,rotation speed 200 r/min,temperature 34℃,and incubation time 48 h.Drip irrigation of maize with fermentation broth increased root length and leaf length by 12.86%and 9.4%,root weight and leaf weight by 6.52%and 6%,respectively.In this study,an endophytic bacterium SYL4 with growth-promoting potential was isolated.The optimized fermentation condition increased the activity of peroxidase(POD)in maize seedlings and effectively promoted the growth of maize seedlings.