Rhizobia inhabiting <em>Clitoria ternatea</em> L. in Anuradhapura District, Sri Lanka: An assessment of stress tolerance and genetic diversity

Abstract

Legume-Rhizobial symbiosis plays a greater agronomical and ecological significance as it provides fixed nitrogen through Biological Nitrogen Fixation. Clitoria ternatea is a leguminous plant that hosts a wide range of rhizobial strains. Even though it is a widely distributed plant, comprehensive information and studies conducted on the rhizobial -C. ternatea symbiosis is lacking in Sri Lanka. This study aimed to identify different stress-tolerant rhizobial strains inhabiting root nodules of C. ternatea growing in seven selected locations of Anuradhapura district of Sri Lanka. Twenty-eight pure rhizobial colonies were isolated and they were separately grown in ½ Lupin broths and were subjected to four different physiological conditions, pH, temperature, salinity, and drought. Most of the isolates were well-grown within the pH range of 5.0-8.0, the temperature range of 30-35 °C and at 0.2% Polyethylene glycol-8000