Dwi Suryanto1*, Aditiya Bungsu1, Steven Taniwan1,
Isnaini Nurwahyuni1 and Artini Pangastuti2
1Department of Biology, Faculty of Mathematics and Natural Sciences, University of Sumatera Utara, Medan, Indonesia.
2Department of Biology, Faculty of Mathematics and Natural Sciences, Sebelas Maret University, Surakarta, Indonesia.
Plant growth promoting bacteria (PGPB) are known for their ability to produce plant hormones and antimicrobial substances, to induce plant resistance, and to solubilize phosphate. In this study, two bacterial isolates Bacillus sp. ST02 and Lactobacillus plantarum ST03, one endophytic bacteria Sp 1E, and one rhizospheric actinomycetes Sp10 R were assayed for their ability in solubilizing phosphate and producing indole acetic acid (IAA), and in affecting chili growth and health. Bacterial ability in solubilizing phosphate was assayed in Pikovskaya’s agar, while the ability in producing IAA was spectrophotometrically measured using Salkowski reagent. To know bacterial potential in promoting plant growth and in reducing fungal disease of Fusarium oxysporum, bacterial isolates were applied in chili seedling grown in small scale field. The results showed that only two isolates Bacillus sp. ST02 and Lactobacillus plantarum ST03 were capable of solubilizing phosphate, but all isolates produced IAA to some extent. Single and combination of ST02 and Sp 10R showed to affect more in increasing plant performance and reducing fungal disease caused by F. oxysporum. This result indicated that the PGPB isolates were considered as a promising microbial inoculant for plant health and growth.
Keywords: indole acetic acid, phosphate solubilizing bacteria, fungal control, plant performance