optimizing bacillus velezensis cultivation and inoculation for arabidopsis thaliana seedling growth enhancement

Rhizobacterial Colonization Detection on Arabidopsis thaliana

There are quantitative and qualitative methods for detecting rhizosphere colonization by a single bacterial strain. For the qualitative method, a strain that constitutively expresses fluorescence should be used, and the fluorescence distribution and intensity should be examined under fluorescence microscopy or laser confocal instruments1,2. Those strategies can well reflect bacterial colonization in situ3, but they are not as accurate as traditional plate counting methods in quantification. Besides, due to the limitation of only displaying partial root zones under the microscope, sometimes it can be influenced by subjective bias. 
Here, we describe a quantitative method, which includes collecting the colonized bacterial cells and counting the bacterial CFUs on a plate. This method is based on dilution and plating by which the colonized strains that were stripped from plant roots can be counted, and the total colonized bacteria number on the root can be calculated4,5. 
First, A. thaliana was cultured in hydroponic conditions, and then bacterial cells were inoculated in the rhizosphere at a final concentration of 0.01 OD600. The infected root tissues were harvested 2 days post-inoculation and washed in sterile water to remove the uncolonized bacterial cells. Further, bacterial cells colonized on the root were collected, diluted in phosphate-buffered saline (PBS) buffer, and plated onto a Luria-Bertani (LB) agar medium. After incubation at 37 &#176;C for 10 h, single colonies on LB plates were counted and normalized to determine the bacterial cells colonized on roots.
This method is highly applicable, has good repeatability, and is more suitable for accurate rhizosphere bacterial colonization determination.

Author Spotlight: Enhancing Rhizobacteria Colonization on Plant Roots for Improved Microbial Fertilizer Efficiency

Measuring Bacterial Colonization on Arabidopsis thaliana Roots in Hydroponic Condition

Our research focuses on the interaction of beneficial rhizobacteria with plant roots. We are looking for the key mechanisms to enhance the colonization of beneficial bacteria, thus improving the efficiency and the stability of microbial fertilizers in the field. The methods for bacterial colonization of plant roots have been extensively studied, but there are still problems.For example, it's hard to measure the colonization on different sites distinctively, In the future we think applying microscope and high throughput counting will help to solve the problems. Our protocol is highly applicable with good repeatability, and it is more suitable for accurate rhizosphere bacteria colonization determination.

Optimizing Bacillus velezensis Cultivation and Inoculation for Arabidopsis thaliana Seedling Growth Enhancement

Research

JoVE Journal

Environment

Measuring bacterial colonization on Arabidopsis thaliana root is one of the most frequent experiments in plant-microbe interaction studies. A standardized ...

Hydroponic Cultivation of Arabidopsis thaliana Seedlings for Bacterial Inoculations

Quantitative Assessment of Bacillus velezensis Colonization on Arabidopsis thaliana Roots