植物杆菌属(Plantibacter)菌株WZW03的分子标记与定殖促生能力

将荧光质粒POT2-RFP转入植物根际促生菌Plantibacter sp. WZW03进行荧光与氨苄青霉素(Amp)抗性标记,研究该菌株在西瓜根际的定殖促生能力。通过生物转化法成功获得遗传稳定的转化子Plantibacter sp. WZW03-P,Plantibacter sp. WZW03-P的生长特性与WZW03无显著差异。在菌浓度相同时,WZW03-P在西瓜幼根表面吸附50 min时吸附量最大,达到(50.87±0.06)×10⁵ cfu·g^-1;当吸附时间相同时,吸附量随着菌株浓度的增大而增加,吸附饱和浓度为(1.27±0.34)×10⁷ cfu·g^-1。在灭菌土和正常土中,WZW03-P数量随投放时间增加而下降,在20 d时活菌数稳定于10⁶ cfu·g^-1水平。WZW03-P对西瓜植株和根系生长具有显著促生效应,且菌株在西瓜根际定殖量较高,具有显著的根际定殖竞争优势。综上,Plantibacter sp. WZW03-P能够较好地吸附且定殖于西瓜根际,并具有促进西瓜生长的功能。

Molecular marker and colonization of Plantibacter sp. WZW03

In this study, the fluorescent plasmid POT2-RFP was transferred into Plantibacter sp. WZW03 as markers and the colonization of strain WZW03 was studied in watermelon rhizosphere. Transgenics with genetically stable transformants were successfully obtained in Plantibacter sp. WZW03-P, and growth characteristic of Plantibacter sp. WZW03-P was not significantly different from that of WZW03. Under the same bacterial concentration, WZW03-P had the largest adsorption capacity of (50.87±0.06)×10⁵ cfu·g^-1 when the watermelon root surface was adsorbed for 50 min. Under the same adsorption time, the adsorption capacity increased with the increase of the strain concentration and the saturation concentration of adsorption was (1.27±0.34)×10⁷ cfu·g^-1. The number of WZW03-P in sterilized soil and normal soil decreased with the prolonged feeding time, and the number of viable bacteria was stable at 10⁶ cfu·g^-1 at 20 d. The promoting effects of WZW03-P were found on the growth of watermelon plants and roots, and the colonization rate of WZW03-P in the watermelon rhizosphere was high, which showed that WZW03-P was provided with a significant competitive advantage in rhizosphere. In conclusion, Plantibacter sp. WZW03-P could colonize well in the watermelon rhizosphere, and promote the growth of watermelon.