Plant growth-promoting potential of bacteria isolated from active volcano sites of Barren Island, India

Abstract

Significance and Impact of the Study: The present research shows diverse plant growth-promoting (PGP) bacteria could be isolated from the active volcano site and suggests that volcano sites represent an ecological niche, which harbours a diverse and hitherto largely uncharacterized microbial population with yet unknown and untapped potential biotechnological applications, for example, plant growth promoters, as evidenced from this study. The outcome of this research may have a practical effect on crop production methodologies in saline and arid environment soils. AbstractTo elucidate the biodiversity of plant growth-promoting (PGP) bacteria in active volcano sites of Barren Island, India, a total of 102 bacteria were isolated and screened for their multifunctional PGP properties. The results revealed that 21 isolates (20Á6%) survived heat shock at 72°C and 11 (10Á8%) isolates were able to grow exposed to 25% NaCl (w/v). In assaying for PGP properties, 59 (57Á8%) isolates shown indole acetic acid (IAA) like substances production, 57 isolates (55Á9%) produced siderophore and 34 (33Á3%) solubilized inorganic phosphate qualitatively. Whereas in the production of extracellular enzymes, 42 isolates (41Á2%) produced protease and amylase, 26 (25Á5%) isolates produced lipase and 24 (23Á5%) isolates produced cellulase. In antagonistic activity, 30 isolates (29Á4%) were found antagonistic against Macrophomina sp., 20 isolates (19Á6%) against Rhizoctonia solani and 15 isolates (14Á7%) against Sclerotium rolfsii. The results based on 16 rRNA gene sequencing revealed that the PGP bacteria belonged to 22 different species comprising 13 genera. Based on multifunctional properties, nine isolates were further selected to determine the PGP in brinjal and chilli seeds. Of the bacteria tested, the isolate BAN87 showed increased root and shoot length of both the crops followed in plant growth promotion by BAN86 and BAN43. The outcome of this research proves plausible practical applicability of these PGPB for crop production in soils of saline and arid environments.

Bacterial Community with Plant Growth-Promoting Potential Associated to Pioneer Plants from an Active Mexican Volcanic Complex

“…Higher nutrient absorption leads to a better development of the root system as well as the aerial part of the plants (branching), and therefore, to an accumulation of dry matter [123]. Inoculation of pepper plants with extremophilic PGPB has been reported previously [39,119], where an improvement in shoot growth and a corresponding increase in root biomass in seedlings were observed. Bacteria isolated from the El Chichón volcano improve the nutrient cycle and thus contribute to the fertility of the volcanic soil.…”

“…In this study, the strain B. subtilis CRM-19 isolated from the tissues of A. glomeratus stood out for its ability to solubilize P and synthesize IAA, siderophores and abundant polysaccharides, and it showed ACC deaminase activity. Researchers have reported the PGPB potential of Bacillus species isolated from extreme environments, demonstrating that this genus definitely contributes to the improvement of plant nutrition [11,39,120]. The multifunctional qualities promoting plant growth appreciated in the isolated strains from El Chichón volcano point out that bacterial communities in the rhizosphere samples are effective in combating stress conditions in plants, thus mitigating the negative effects produced by heavy metals and other soil contaminants.…”

“…The bacterial isolates were grown in CAS-agar medium [chromeazurol-S (CAS), iron (III) and hexadecyl trimethyl ammonium bromide (HDTMA)] at 28-30 • C for 5 days. The production of bacterial siderophore was detected by a color change from blue to a fluorescent orange surrounding the colonies [39].…”

BACTERIAL DIVERSITY WITH PLANT GROWTH-PROMOTING POTENTIAL ISOLATED FROM Agave americana RHIZOSPHERE

“…Production of siderophore. Bacterial isolates were grown in CAS-agar medium [chromeazurol-S (CAS), iron (III) and hexadecyl trimethyl ammonium bromide (HDTMA)] at 28-30 °C for 5 days until there was a color change from blue to a fluorescent orange surrounding the bacterial colonies indicating the production of siderophore (Amaresan et al, 2013).…”

An overview of siderophores for iron acquisition in microorganisms living in the extreme

“…High-temperature environments are widely spread on Earth, from thermal hot springs in Yellowstone National Park (Beam et al 2014;Kozubal et al 2013;Wu et al 2013a) and Mexico (Brito et al 2014), to deep-sea vents (Kaye et al 2011; Pettit 2011), mines (Gounder et al 2011) and volcanoes (Amaresan et al 2014;Connell et al 2009). A diverse population of organisms are found, representing the three branches of the tree of life: eukaryotes (Connell et al 2009), archaea (Beam et al 2014;Hedlund et al 2013;Kozubal et al 2013) and bacteria (Kaye et al 2011;Temirov et al 2003).…”