Novel finding of Paulownia fortunei endophytic rhizobia in China

Previous research has mainly focused on breeding, timber supply, and physiological-biochemical characteristics of Paulownia fortunei. However, there has been limited attention given to its endophytic rhizobia and its potential benefits for plant growth due to a lack of knowledge about the existence of root nodules. In this study, we extracted 9 bacterial strains from the root nodules after occasionally discovering the nodular-like structure in uncultivated 3-year P. fortunei roots and then sequenced the 16S rDNA and nifA sequencing to conduct the bacterial strain identifications. We then determined the carbon use capability and nitrogenase activity of the bacterial strains. The result of 16S rDNA sequencing indicated that the endophytic rhizobia belongs to the genus Agrobacterium, Rhizobium, Herbaspirillum, and Burkholderia. The results of nifA sequencing indicated that the nifA gene was sequenced in strain PG-3, PG-5, PG-6, PG-7, PG-8, rather than in strain PG-1, PG-2, and PG-4. Beside..., We used a vernier caliper, band tape, and length rod to measure the plant height, stem diameter and dry biomass three months after planting to investigate the effects of bacterial strain applications on Paulownia seedling growth. The nitrogenase activity of 9 endophytic rhizobia strains was measured colorimetrically at 450 nm (N = 3) using the nitrogenase ELISA kit (Jining, Tongwei, Shanghai, China) according to the manufacturer’s instructions., , # **Novel finding of *Paulownia fortunei* endophytic rhizobia in China**

## Description of the data and file structure

The raw data contains plant diameter (unit: mm), height (unit: cm), and dry biomass (unit: g) after bacterial applications, as well as nitrogenase activity (unit: μL/g/h) of nine bacterial strains. Someone who uses the data to do further analysis will need to take the fact that the bacterial strains are isolated from Paulownia fortunei into consideration.

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