Isolation and characterization of mesophilic bacteria from rhizosphere of plant rice (Oryza sativa) from Lodhran, Pakistan

The present study demonstrated isolation and characterization of 48 bacterial strains (ABOs01-ABOs48) from rhizosphere of rice plant (Oryza sativa) of Rind Jada (Kahror Pacca), Punjab, Pakistan. Morphological studies including colony color, bacterial shape and gram staining were performed and colonies were observed to be either orange yellow, light yellow, pink, greenish yellow, white, or off-white in appearance. Gram staining showed that out of 48 isolates, 38 were gram positive and 10 were gram negative. Various Biochemical tests were performed to identify these strains; the results were used to identify these strains at the species levels. These strains belongs to the following species Erwinia stewartii (13), Klebsiella terrigena (9), Klebsiella pneumonia susp. Ozaene (8), Serratia plymuthica (6), Yersinia (5), Escherichia blattae (5), 1 Edwardsiella ictaluri (1), and Obesumbacterium proteus (1). Additionally, amylase test showed that 39 strains were positive while 9 were negative. Conversely, all strains were negative for cellulase production. Finally, Antibiotics resistance showed 23 isolates were sensitive vs 25 resistant to ampicillin and 4 isolates were resistant vs 44 sensitive to penicillin. These findings suggested a great microbial diversity in rice plant rhizosphere which demands more investigations for agricultural and industrial purposes.