Nitrogen source affects glutamine synthetase activity in Pantoea sp.; bacterium inoculation promotes rice seedlings' growth

This study investigated the influence of different sources of nitrogen on Glutamine synthetase (GS) activity of Pantoea sp. strain 9C and the effect of inoculation with the bacterium on the growth medium of rice seedlings. The growth curves of 9C showed lowest cell concentration in LGI medium free of nitrogen and highest cell concentration in LGI medium supplied with 5 mmol/L of serine or asparagine. The measure of GS activity of 9C was accomplished by culturing the bacteria for 96 h using the biosynthetic method. Cellular rupture was carried out by ultrasonic waves or lysozyme. GS activity was detected in cytosol and in cellular debris. GS activity in supernatant was influenced by the source of nitrogen; alanine increased the activity while ammonium inhibited it. The bacterium increased the seedlings fresh weight and height of the shoot, and the length and number of rice seedlings’ roots.