* To whom all correspondence should be addressed. E-mail: dwisuryanto@usu.ac.id JOURNAL OF PURE AND APPLIED MICROBIOLOGY, Sept. 2017. Vol. 11(3), p. 1379-1386 Application of a Single and Combination of Plant-growth Promoting Bacteria and Actinomycete to Increase Chili (Capsicum annuum L.) Health and Growth Dwi Suryanto 1 *, Aditiya Bungsu 1 , Steven Taniwan 1 , Isnaini Nurwahyuni 1 and Artini Pangastuti 2 1 Department of Biology, Faculty of Mathematics and Natural Sciences, University of Sumatera Utara, Medan, Indonesia. 2 Department of Biology, Faculty of Mathematics and Natural Sciences, Sebelas Maret University, Surakarta, Indonesia. http://dx.doi.org/10.22207/JPAM.11.3.19 (Received: 25 February 2017; accepted: 16 April 2017) 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. To control plant pathogenic fungi and to increase plant performance, ones mainly use chemical compounds such as pesticides and fertilizer. Recently, many efforts have been conducted to reduce chemical pesticide and fertilizer application by exploring a possibility of utilization of biological agent as biofertilizer and biocontrol agent. Among biocontrol and biofertilizer, bacteria are the most interesting group of organisms that have already been utilized as beneficial microorganism. A diverse group of beneficial microorganisms have been found, but their roles in environments have not been fully understood. Many studies have been conducted to isolate and to utilize plant-benefit microbes such as plant growth promoting bacteria (PGPB). These include free-living, specific symbiotic, and cyanobacteria (Glick, 2012). PGPB are group of bacteria enhancing and protecting plant growth through a wide variety of mechanisms such as by producing plant hormones, increasing the availability of soil nutrient, and controlling plant pathogen by inducing plant resistance or by producing antimicrobial compounds (Chakraborty et al.,