Abstract
Here we describe a simple method to quantify the number of viable bacteria (e.g., Enterobacter sp. SA187) that colonize the root system of Arabidopsis thaliana.
Keywords: Arabidopsis thaliana, Colony forming unit, Endophytes
Background
Colonization of roots by inoculated bacteria is an important step in the interaction between beneficial bacteria and the host plant. Enterobacter sp. SA187 is an endophytic bacterium that has been isolated from root nodules of the indigenous desert plant Indigofera argentea (Andrés-Barrao et al., 2017; Lafi et al., 2017). SA187 promotes the growth of the model plant Arabidopsis thaliana under diverse abiotic stresses such as salinity, drought or high temperature, demonstrating an important potential for application as Plant Growth Promoting Bacteria (PGPR) to improve abiotic resistance and yield of crops in arid lands. SA187 can colonize both roots and shoots of A. thaliana on ½ MS agar plates or in soil (de Zélicourt et al., 2018). To follow the fate of inoculant strain SA187 on the non-host plant A. thaliana, we applied a routinely cultivation-dependent method. This protocol has been successfully used to mounter the bacterial number colonized both root and shoot of the A. thaliana plant under different abiotic stresses (de Zélicourt et al., 2018).
Materials and Reagents
Equipment
Procedure
Data analysis
Calculate the number of bacteria (CFU) per milliliter or gram of sample by dividing the number of colonies by the dilution factor The number of colonies per ml reported should reflect the precision of the method and should not include more than two significant figures. The CFU/ml can be calculated using the following formula: CFU/ml = (number of colonies x dilution factor)/volume of culture plate CFU value could also be divided by the root/shoot fresh weight to get CFU/mg plant material.
Acknowledgments
The authors would like to express their gratitude to all members of the Hirt lab and the technical support team. This publication is based upon work supported by the King Abdullah University of Science and Technology (KAUST), base fund (No. BAS/1/1062-01-01) for HH. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
References
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