黄曲霉生防菌DJB5在玉米种子中的定殖研究

Colonization of the Biocontrol Bacterial Strain DJB5 against Aspergillus flavus in Maize Grains

【目的】研究生防菌DJB5在玉米种子中的定殖能力与规律。【方法】利用自然转化方法把pHT01-P43GFPmut3a质粒导入生防菌DJB5中,测定转化子的稳定性、GFP标记菌(DJB5-GFP)的生长趋势和生物膜形成能力,并通过室内平板对峙和玉米活体试验对比DJB5-GFP和野生型菌株的防效。【结果】pHT01-P43GFPmut3a质粒可以在DJB5中稳定遗传,GFP基因的导入未影响其生防活性。玉米储藏试验表明:在不同玉米含水量和贮存温度下,含水量越高,DJB5的定殖能力越强,30%含水量下,定殖量最高可以达到10^7 CFU/g数量级;DJB5在28~35℃下的定殖量大于28℃以下和35℃以上。【结论】生防菌DJB5具有在玉米收获到贮藏期间防治黄曲霉的潜力。

[Purpose]To understand the colonization of the biocontrol bacterial strain DJB5 in maize grains and its regularities.[Method]Plasmid pHT01-P43GFPmut3a was transformed into DJB5 cells for fluorescence tagging by natural transformation.The stability of plasmid,growth tendency and biofilm-forming ability of DJB5-GFP were tested,and the control efficiency difference between DJB5 and DJB5-GFP strains was analyzed using plate antagonism bio-assay and grain storage experiment.[Result]Plasmid pHT01-P43GFPmut3a could keep stable,and its introduction had no significant negative load on DJB5 growth and biocontrol activity.The storage experiment showed that under different grain moisture contents and storage temperatures,the number of DJB5-GFP increased with the increase of grain moisture contents and was as high as 107 CFU/g(orders of magnitude)at the grain moisture content of 30%;colonization was greater at storage temperature ranging from 28℃to 35℃than that below 28℃and above 35℃.The result indicated that DJB5 had the potential for controlling Aspergillus flavus on maize grains during post-harvest storage.