Plant growth promoting capability and genetic diversity of bacteria isolated from mud volcano and lime cave of Andaman and Nicobar Islands

Abstract

Twenty four bacterial strains from four different regions of mud volcano and lime cave were isolated to estimate their diversity, plant growth promoting and biocontrol activities to use them as inoculant strains in the fields. An excellent antagonistic effect against four plant pathogens and plant growth promoting properties such as IAA production, HCN production, phosphate solubilization, siderophore production, starch hydrolysis and hydrolytic enzymes syntheses were identified in OM5 (Pantoea agglomerans) and EM9 (Exiguobacterium sp.) of 24 studied isolates. Seeds (Chili and tomato) inoculation with plant growth promoting strains resulted in increased percentage of seedling emergence, root length and plant weight. Results indicated that co-inoculation gave a more pronounced effects on seedling emergence, secondary root numbers, primary root length and stem length, while inoculation by alone isolate showed a lower effect. Our results suggest that the mixed inocula of OM5 and EM9 strains as biofertilizers could significantly increase the production of food crops in Andaman archipelago by means of sustainable and organic agricultural system.

Characterization of Tomato-associated Rhizobacteria Recovered from Various Tomato-growing Sites in Tunisia

“…These isolates exhibited a large metabolic activity and were shown able to metabolize a wide range of carbon sources with the increase of the incubation duration. Furthermore, based on their metabolic profiles obtained using Biolog system, the selected isolates were grouped into eight major clusters at each incubation duration (24,48 and 120 h of incubation) and their AWCD was found be correlated to Shannon diversity index.…”

“…The average AWCD values recorded at the three incubation durations (24,48 and 120 h of incubation) ranged between 0.18 and 3.19. The most important values were noted for isolates E. cloacae B4 (KT923050) and C. jejuense B11 (KU158886).…”

“…Phosphate solubilization: Phosphate solubilization ability of isolates was assessed qualitatively using a modified Pikovskaya's agar medium containing tricalcium phosphate according to Venkadesaperumal et al [24] method. Briefly, each bacterial culture was spot inoculated in the centre of a Petri plate and incubated at 28°C for 7 days.…”

Seedling Emergence Comparison of Several Romanian Tomato and Pepper Varieties

“…For instance, rhizobacteria Pseudomonas fluorescens and Bacillus mycoides were shown to improve wheat seedling emergence and plant biomass (Czaban et al, 2004;Sivaramaiah et al, 2007). In addition, bacteria isolated from mud volcano and lime cave of Andaman and Nicobar Islands increased the percentage emergence for chili and tomato seedlings (Venkadesaperumal et al 2014). Levy and Taylor (2003) published a study regarding the effects of several composts and pulp mill solids on tomato early growth.…”

Evaluation of the Effectiveness of Tomato-Associated Rhizobacteria Applied Singly or as Three-Strain Consortium for Biosuppression of Sclerotinia Stem Rot in Tomato

“…One day after pathogen challenge, seedlings were transplanted into pots (16 cm in diameter) containing pathogeninfected peat [22]. a Molecular identification was performed by amplification and sequencing of 16S rRNA and rpoB genes [27] b Lipopeptide production ability was confirmed by amplification and sequencing of genes encoding for Fengycin A (Fen A ) and Bacillomycin D (Bac D) biosynthesis [27] c PGPR traits: Plant growth promoting rhizobacteria traits IAA: Indole-3-acetic acid production determined according to Ghodsalavi et al [48] protocol e P. solubilization: Phosphate solubilization ability assessed qualitatively using a modified Pikovskaya's agar medium containing tricalcium phosphate [49] f Production of siderophore was assessed by spot inoculation onto Chrome Azurol S agar medium [50]. Production was scored as negative (−), low (+), middle (++) and high (+++) All isolates were negative for hypersensitive reaction (HR) on tobacco leaves Positive reaction (+); Negative reaction (-) Pathogen-inoculated seedlings watered with SDW only (water control) or treated with a commercial fungicide, i.e., Previcur Energy TN (632.6 g/L Propamocarb-Hcl+332.6 g/L Fosethyl-Al) applied at 0.5 mL/ mL, were used as controls.…”