J Biochem Tech (2014) 5(4):808-813 ISSN: 0974-2328 Abstract Nineteen bacterial strains were isolated from vermisources and screened for Indole-3-acetic acid (IAA) production among them only nine strains produce IAA and they were identified as Streptococcus spp., Micrococcus spp., Klebsiella spp., Bacillus spp., Enterobacter spp., Escherichia spp., Alcaligenes spp., Erwinia spp., and Pseudomonas spp. Among all other strains Bacillus sp. showed the higher IAA production hence selected for further molecular analysis and confirmed as Bacillus cereus. The B. cereus was grown in nutrient broth supplemented with different concentrations (1, 2, 3, 4 and 5mg/ml) of tryptophan for seven days at pH 7 and at 37 º C. Crude IAA was used for in vitro phytostimulatory studies using Vigna unguiculata (L.) Walp. The plant growth parameters were analyzed at different day intervals (5, 10 and 15 days). Supplementation of 5 ml crude IAA (2mg/ml of tryptophan) dynamically enhances the plant growth parameters after 15 days. Keywords: Vermicompost, Tryptophan, Indole-3-acetic acid, Bacillus cereus, Vigna unguiculata (L.) Walp Introduction To enhance the fertility status of soil, the natural way of feeding the soil with different types of organic inputs has been practiced in recent years. There is an increasing interest in the potential of vermicompost, as plant growth media and as soil amendments. Vermicompost is a product of biodegradation and stabilization of organic materials by interaction of earthworms and microorganisms. It is rich in available nutrients required for plant growth and colonizing microorganisms capable of fertilizing the soil (Karmegam and Daniel, 2000). Phytostimulatory effects of Bacillus strains are well documented and several mechanisms have been suggested for the growth improvement activity of this group of plant growth promoting Rhizobacteria (PGPR). Bacillus spp. have several advantages over other PGPR in that they posses several growth promoting traits such as production of phytohormones, secretion of antibiotics, induction of systemic resistance and their use as biopesticides (Reva et al., 2004; Swiecicka et al., 2008). Inoculation of PGPR can elicit physiological changes in plants that are mainly mediated by secondary metabolites especially phytohormones produced by microbes. Bacteria can influence plant growth directly through the production of phytohormones and indirectly through the production of biocontrol agents against soil borne pathogens (Glick et al., 2007). PGPR based products mostly contain strains of Bacillus that may have direct agricultural application because of long term viability of these sporogenous bacteria. Therefore, Bacillus spp. has the potential to be applied as booster inoculants to increase the efficacy of plant growth promotion and elicitation of systemic disease protection in the field (Kloepper et al., 2004). Auxins represent a wide group of compounds which are derivatives of the indole ring. Auxins are believed to be essential phytohormones for plant life. Auxins at higher concentrations stimulate the growth of shoots, inhibit that of roots, but concentrations of lower magnitude stimulate root growth. Indole-3-acetic acid (IAA) is the main auxin in plants and it controls many important physiological processes. IAA producing bacteria can potentially interfere with such processes based on the input of IAA into a plants auxin pool (Raja et al., 2008; Sivasankari and Daniel, 2010). This research work was carried out with the main objective to evaluate the IAA production potential of vermisources associated gram- positive bacilli and their phytostimulatory effect on V. unguiculata under gnotobiotic conditions. Materials and Methods Vermicompost preparation For the present study epigeic earthworms, Eudrilus eugeniae (Kinberg) and Eisenia fetida (Savigny) were collected from the breeding stock of the Department of Biology, Gandhigram Rural Institute-Deemed University, Gandhigram, Tamilnadu, India and leaf materials of Gliricidia sepium Jacq, Leucaena Effect of PGR producing bacterial strains isolated from vermisources on germination and growth of Vigna unguiculata (L.) Walp. Balayogan Sivasankari, Marimuthu Anandharaj * , Thilagavathy Daniel Received: 10 September 2013 / Received in revised form: 14 June 2014, Accepted: 28 June 2014, Published online: 25 December 2014 © Biochemical Technology Society 2014 Balayogan Sivasankari, Marimuthu Anandharaj * , Thilagavathy Daniel Department of Biology, Gandhigram Rural Institute-Deemed University, Gandhigram-624302, Dindigul, Tamilnadu, India Tel.: 0091 9688893123; *Email: anandharaj49@gmail.com