**1. Tomato and plant growth promoting rhizobacteria**

Tomato is a potential horticultural crop for cultivation due to its high economic value. The production of the crop in Indonesia was 864,798 t/ha in 2008–2011, with an average productivity of 21.5 t/ha, which is below production levels of 100 t/ha in the United States and Europe.

Rhizobacteria of *Pseudomonas* spp. group are beneficial for plants, improving soil fertility, and function as biological control agents for plant pathogens and have the potential of increasing plant resistance (induced systemic resistance; ISR) [1]. Rhizobacteria plays an indirect role as a biological fertilizer and biological stimulant through the production of plant growth hormones, such as indole acetic acid (IAA), gibberellins, cytokinins, ethylene, and solubilizing minerals. These organisms also indirectly function to inhibit pathogenic microorganisms, through the formation of siderophores and antibiotics [1, 2].

Rhizobacteria, such as *P. fluorescens*, *P. putida*, and *P. aeruginosa*, are beneficial to plants as plant growth promoting rhizobacteria (PGPR), with the ability to control plant diseases [3, 4]. Research on the benefits of *Pseudomonas* spp. still continues to better understand its mechanism in spurring plant growth.

*Bacillus* sp. is a Gram-positive bacteria used in controlling root disease. These bacteria produce spores that can be stored for long periods and are easily inoculated into the soil. Previous research has shown that the bacteria *Bacillus* strains PRBS-1 and AP-3 proved to inhibit the growth of pathogenic fungi (*Rhizoctonia solani*, *Colletotrichum truncatum*, *Sclerotinia sclerotiorum*, *Macrophomina phaseolina*, and *Phomopsis* sp.) in soybean seeds and enhanced the growth of plants [5].

Rhizobacteria can be used as a bioprotectant that can suppress the development of plant pests/diseases, as a biostimulant that for production of indole acetic acid (IAA), cytokines, and gibberellin, and as a biofertilizer for increasing nutrient availability to plants [6].
