Received: 24-06-2022 / Accepted: 22-11-2022
Endophytic bacteria living in the plant tissues support plant growth by synthesizing IAA and siderophore, inorganic soluble phosphate, and increasing disease resistance of the host plants. This study aimed to evaluate the effects of carbon and nitrogen sources, pH, temperature, and time of incubation on the concentration of IAA synthesized by two endophytic bacterial strains, HY9 and TT3, isolated from Lonicera japonica. Under various suitable culture conditions, maximum IAA of HY9 and TT3 strains was produced at pH=7 (42.9 µg/ml and 49.07 µg/ml, respectively), 35C (53.49 µg/ml and 56.73 µg/ml), and 4 days of incubation (51.47 µg/ml and 53.76 µg/ml). The suitable carbon and nitrogen sources were saccharose and NH4Cl. Comparing the nucleotide sequence of 16S rRNA of TT3 strain with nucleotide sequences of 16S rRNA of other bacterial strains on GenBank revealedthat TT3 strain had a very closed relationship with Klebsiella variicola strain 1, thus,strain TT3 was named Klebsiella variicola TT3.