title: Gibberellin-producing Promicromonospora sp. SE188 improves Solanum lycopersicum plant growth and influences endogenous plant hormones.
abstract: Plant growth-promoting rhizobacteria (PGPR) producing gibberellins (GAs) can be beneficial to plant growth and development. In the present study, we isolated and screened a new strain of Promicromonospora sp., SE188, isolated from soil. Promicromonospora sp. SE188 secreted GAs into its growth medium and exhibited phosphate solubilization potential. The PGPR produced physiologically active (GA(1) and GA(4)) and inactive (GA(9), GA(12), GA(19), GA(20), GA(24), GA(34), and GA(53)) GAs in various quantities detected by GC/MS-SIM. Solanum lycopersicum (tomato) plants inoculated with Promicromonospora sp. SE188 showed a significantly higher shoot length and biomass as compared to controls where PGPR-free nutrient broth (NB) and distilled water (DW) were applied to plants. The presence of Promicromonospora sp. SE188 significantly up-regulated the non C-13 hydroxylation GA biosynthesis pathway (GA(12)→GA(24)→GA(9)→GA(4)→ GA(34)) in the tomato plants as compared to the NB and DW control plants. Abscisic acid, a plant stress hormone, was significantly down-regulated in the presence of Promicromonospora sp. SE188. Contrarily, salicylic acid was significantly higher in the tomato plant after Promicromonospora sp. SE188 inoculation as compared to the controls. Promicromonospora sp. SE188 showed promising stimulation of tomato plant growth. From the results it appears that Promicromonospora sp. SE188 has potential as a bio-fertilizer and should be more broadly tested in field trials for higher crop production in eco-friendly farming systems.
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu 702-701, Republic of Korea.
authors.forename: Sang-Mo
authors.initials: SM
authors.lastname: Kang
authors.forename: Abdul Latif
authors.initials: AL
authors.lastname: Khan
authors.forename: Muhammad
authors.initials: M
authors.lastname: Hamayun
authors.forename: Javid
authors.initials: J
authors.lastname: Hussain
authors.forename: Gil-Jae
authors.initials: GJ
authors.lastname: Joo
authors.forename: Young-Hyun
authors.initials: YH
authors.lastname: You
authors.forename: Jong-Guk
authors.initials: JG
authors.lastname: Kim
authors.forename: In-Jung
authors.initials: IJ
authors.lastname: Lee
mesh_terms: D000040:Abscisic Acid / Q000737:chemistry; D000192:Actinomycetales / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D005875:Gibberellins / Q000096:biosynthesis* / Q000737:chemistry; D018551:Solanum lycopersicum / Q000254:growth & development* / Q000378:metabolism* / Q000382:microbiology; D010710:Phosphates / Q000737:chemistry; D010937:Plant Growth Regulators / Q000378:metabolism*; D020156:Salicylic Acid / Q000737:chemistry; D012995:Solubility
chemical_list: D005875:Gibberellins; D010710:Phosphates; D010937:Plant Growth Regulators; D000040:Abscisic Acid; D020156:Salicylic Acid