Rhizosphere colonization is a key requirement for the application of plant growth-promoting rhizobacteria (PGPR) as a biofertilizer. Signaling molecules are often exchanged between PGPR and plants, and genes in plants may respond to the action of PGPR. Here, the luciferase luxAB gene was electrotransformed into Pseudomonas sp. strain TK35, a PGPR with an affinity for tobacco, and the labelled TK35 (TK35-L) was used to monitor colonization dynamics in the tobacco rhizosphere and evaluate the effects of colonization on tobacco growth and root development. The transcript levels of the hydroxyproline-rich glycoprotein HRGPnt3 gene, a lateral root induction indicator, in tobacco roots were examined by qPCR. The results showed that TK35-L could survive for long periods in the tobacco rhizosphere and colonize new spaces in the tobacco rhizosphere following tobacco root extension, exhibiting significant increases in root development, seedling growth and potassium accumulation in tobacco plants. The upregulation of HRGPnt3 transcription in the inoculated tobacco suggested that TK35-L can promote tobacco root development by upregulating the transcript levels of the HRGPnt3 gene, which promotes tobacco seedling growth. These findings lay a foundation for future studies on the molecular mechanism underlying the plant growth-promoting activities of PGPR. Furthermore, this work provided an ideal potential strain for biofertilizer production.

根际定植是应用促进植物生长的根际细菌（PGPR）作为生物肥料的关键要求。信号分子通常在PGPR和植物之间交换，并且植物中的基因可能对PGPR的作用作出反应。在这里，荧光素酶luxAB基因被电转化为假单胞菌sp。TK35菌株（一种对烟草具有亲和力的PGPR）和标记的TK35（TK35-L）用于监测烟草在根际中的定殖动态，并评估定殖对烟草生长和根系发育的影响。富含羟脯氨酸的糖蛋白HRGPnt3的转录水平通过qPCR检测烟草根中的侧向根诱导指示剂基因。结果表明，TK35-L可以在烟草根际中长期生存，并在根系扩展后在根际中占据新的空间，根系发育，幼苗生长和钾素积累显着增加。接种烟草中HRGPnt3转录的上调提示TK35-L可通过上调HRGPnt3的转录水平来促进烟根发育基因，促进烟草幼苗生长。这些发现为未来研究PGPR促进植物生长的分子机制奠定了基础。此外，这项工作为生物肥料生产提供了理想的潜在菌株。