Indole-3-acetic acid (IAA) production ability of Serratia nematodiphila CT-78

Serratia nematodiphila CT-78 was shown to be antagonistic against Xanthomonas oryzae pv. oryzae thus capable of reducing rice bacterial leaf blight under field conditions. The aim of this study is to investigate the indole-3-acetic acid (IAA) production ability of this bacterium which might contribute to its growth promotion effects in addition to the observed effects against the disease. The IAA production was detected at 2, 4, 6 and 8 days after bacterial inoculation (DAI) in the Nutrient Broth (NB) medium suplemented with 0.1 g/L tryptophan. Three bacterial suspensions were tested, i.e., 10⁵, 10⁶ and10⁷ CFU/mL, where the highest IAA amount (16,17 µg/mL) was detected in the 10⁵ CFU/mL suspension at 8 DAI.