Screening of indole-3-acetic acid PGPB from three agricultural systems at Nakhon Pathom, Thailand

Abstract. Homthong M, Kaewpuk W, Yamsuan S, Thongsima A, Mokkapan K, Pikulthong V. 2022. Screening of indole-3-acetic acid PGPB from three agricultural systems at Nakhon Pathom, Thailand. Biodiversitas 23: 5935-5941. Plant growth-promoting bacteria (PGPB) are associated with plant roots and enhance growth via a variety mechanisms, including fixation atmospheric nitrogen, solubilization phosphorus, phytohormone synthesis, phenolic compound stimulation. Sixty-five isolated the in Pathom were screened for IAA production. The results showed that seven isolates—C01-28, C02-48, C02-51, G01-34, G03-25, G03-38, O02-46—produced under L-tryptophan as precursor values 9.08 ± 0.51, 68.64 29.07, 40.67 18.04, 10.65 1.07, 63.30 1.15, 37.73 1.80, 121.28 15.20 mg mL-1, respectively. Capability on traits revealed none isolates stimulated ten-morning glory (Ipomoea aquatica Forsk.) seedling growth, which was not significantly different control. Isolates O02-46 enhanced salicylic (SA) seedlings most, showing 7.18 1.78 µg g-1 fresh weight, while G01-34 (PC) production most 218.18 29.55 GAE extract, 16S rRNA analysis O02-46, C02-51 identified similar to Paenibacillus alvei 99.20% (Accession number AY826588.1), Bacillus megaterium 79.91% MH031358.1), sp. 98.57% JF322976.1), Lysinibacillus fusiformis 99.61% HE610782.1).