Selection of bacteria producing indole-3-Acetic acid and its application on oil palm seedlings (Elaeis guineensis Jacq.)

Abstract

Aims: Oil palm (Elaeis guineensis Jacq.) is the largest plantation crop in Indonesia and has a high economic value. The use of synthetic fertilizers and pesticides is the largest plantation expenditure and causes many environmental problems. The objectives of the research were to select indole-3-acetic acid (IAA) producing bacteria and test its application in oil palm seedlings. Methodology and results: The IAA producing bacteria selected in this research consisted of 9 chitinolytic and 16 cellulolytic bacteria. Screening results based on colorimetric method showed that bacterial isolates, KAHN 15.12 and Bacillus thuringiensis SAHA 12.08, has the ability to produce IAA. Both isolates were negative on hypersensitivity tests to the plant. Quantitative measurement using HPLC showed IAA was produced by peaks at a retention time of 21 to 22min was the same as IAA standard. KAHN 15.12 had 99% of identify with Serratia marcescens when identified based on 16S rRNA gene sequences. The application of S. marcescens KAHN 15.12 and B. thuringiensis SAHA 12.08 on oil palm seedlings showed greater improvement in oil palm seedling growth than application of chemical fertilizer. The isolates increased the number of seedling lateral roots by up to 60.7-65%. Conclusion, significance and impact of study: Bacterial isolates KAHN 15.12 and SAHA 12.08 can promote the growth of oil palm seedling roots. The isolates have potential as a biological fertilizer and to reduce chemical fertilizer usage on oil palm seedlings.