Isolation and characterization of endophytic plant growth-promoting or stres1 s regulating bacteria associated with the halophyte Prosopis strombulifera

SGROY VERÓNICA; CASSÁN FABRICIO; MASCIARELLI OSCAR; DEL PAPA M. FLORENCIA; LAGARES ANTONIO; LUNA VIRGINIA

APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

Springer

Año: 2009

0175-7598

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> This study was designed to isolate and characterize endophytic bacteria from the halophyte Prosopis strombulifera and to evaluate in vitro the bacterial mechanisms potentially related to the plant growth promotion or stress mitigation. Isolates were subject to a BOX-PCR, grouped according to similarity, and identified by amplification and sequences of 16S rDNA. Nitrogen fixation, phosphate solubilization, siderophore production, and antifungal, protease, and 1-aminocyclopropane-1-carboxylate deaminase activities were evaluated in defined medium. Phytohormone production, as indole-3-acetic acid, zeatin, gibberellic acid and abscisic acid was determined by gas chromatography-mass spectrometry.  A 16S rDNA sequence indicated that Ps7 has high homology with the Lysinibacillus fusiformis ASC8; Ps8, with Bacillus subtilis; Ps9, with Brevibacterium halotolerans strain DSM 8802; Ps14, with Bacillus licheniformis isolate ADB4; Ps19, with Bacillus pumilus; Ps27 with Achromobacter xylosoxidans, and Ps30, with Pseudomonas putida. All strains were able to fix nitrogen and produce some phytohormones, Ps30 was able to produce siderophores. ACC deaminase activity was positive for all strains except Ps7 and antifungal and protease activities were demonstrated for Ps9 and Ps19. These results suggest an "endophytic bacterial consensus", in which each strain contributes one or more mechanisms that jointly determine a global answer in the plant.