类芽孢杆菌QHZ11-gfp在马铃薯植株上的定殖特征及促生效果

The colonization characteristics of Paenibacillus jamilae QHZ11-gfp in potato plants and its growth-promoting effect

摘要:

[背景] 生防菌在作物根系的有效定殖是其功能发挥的前提，而直观的跟踪技术和有效的定量方法是研究生防菌根系分布规律的重要工具。[目的] 研究马铃薯黑痣病病原菌立枯丝核菌（Rhizo ctonia solani） JT18的拮抗菌QHZ11在马铃薯植株上的定殖特征及对马铃薯的促生效果。[方法] 采用绿色荧光蛋白（Green Fluorescent Protein，GFP）对QHZ11进行标记，将标记菌株菌悬液、生物有机肥和无菌水分别接种至灭菌土壤，通过激光共聚焦显微技术和实时荧光定量PCR等方法观察和测定标记菌株在马铃薯植株不同部位的定殖特征、数量变化及对马铃薯的促生效果。[结果] pHAPII质粒成功导入QHZ11并可稳定遗传40代，记为QHZ11-gfp；菌株标记前后的菌落形态、生长曲线和对R.solani JT18的拮抗能力等基本一致。从第7天开始，相继在马铃薯芽上和根上发现了绿色荧光，说明QHZ11-gfp成功定殖到了马铃薯的芽、根等部位。QHZ11-gfp在根系和匍匐茎的定殖数量均呈现先升高至块茎形成期达到峰值后下降的趋势，并且在整个生育期根系的定殖数量始终大于匍匐茎。菌悬液和生物有机肥处理均显著促进了马铃薯根系的生长，并通过增加株高等农艺性状提高了块茎产量。其中，生物有机肥处理在各部位的荧光强度、定殖数量和对马铃薯的促生效果均显著优于菌悬液。[结论] QHZ11-gfp可在马铃薯植株上成功定殖并对马铃薯有良好的促生效果，将其制成生物有机肥促进了其定殖，使促生效果也更好。

关键词:类芽孢杆菌;绿色荧光标记;定殖特征;实时荧光定量PCR;促生作用

Abstract:

[Background] The effective colonization of biocontrol bacteria in crop roots is the prerequisite for their functions, and intuitive tracking technology and effective quantitative methods are important tools for studying the roots' distribution of biocontrol bacteria.[Objective] To study the colonization characteristics of QHZ11 (antagonistic bacteria of Rhizoctonia solani JT18) in potato plants and its growth-promoting effect on potato. [Methods] Using green fluorescent protein (GFP) to label QHZ11, and separately inoculating the labeled bacterial suspension, bio-organic fertilizer and sterile water into the sterilized soil. Using laser confocal microscopy technology and real-time fluorescent quantitative PCR to study the colonization characteristics and quantitative changes of labeled strain in different parts of potato plants and its growth-promoting effect on potato. [Results] The pHAPII plasmid was successfully transformed into QHZ11 and could be inherited stably for 40 generations in QHZ11-gfp, recorded as QHZ11-gfp; the colony morphology, growth curve and antagonistic ability against R. solani JT18 of strain before and after the labeling were basically same. Starting from the 7th day, green fluorescence successively were found on the potato buds and roots, indicating that QHZ11-gfp successfully colonized on the potato buds, roots, etc. The quantity of colonization of QHZ11-gfp in the roots and stolons both showed a trend of first increasing to the peak in tuber formation period and then decreasing and in the whole growth period, the quantity of colonization of QHZ11-gfp in the roots was always>stolons. Both bacterial suspension and bio-organic fertilizer treatments significantly promoted the growth of potato roots, increased the tuber yield by increasing plant height, etc. The fluorescence intensity, the quantity of colonization and the growth-promoting effect on potato of bio-organic fertilizer treatment were significantly better than those of bacterial suspension. [Conclusion] QHZ11-gfp can be successfully colonized on potato plants and has a good growth-promoting effect on potatoes. Making it into bio-organic fertilizer promotes its colonization and makes the growth-promoting effect better.

Key words:Paenibacillus jamilae;green fluorescent labeling;colonization characteristics;real-time fluorescent quantitative PCR;growth promotion