Global Advanced Research Journal of Microbiology (GARJM) ISSN: 2315-5116
April, 2016. Vol. 5(3), pp 023-031
Copyright © 2016 Global Advanced Research Journals
Full Length Research Paper
Isolation of Rhizobacteria and Micro Algae from Saline Soil and Production of Plant Growth Promoters
Shimaa E. Ibrahim *, Entesar A. Ahmed *, Heba Sh. Shehata **, Reda M. El Shahat ** and Rawheya A. Salah El Din *
*Botany and Microbiology Department, Faculty of Science, Al-Azhar University (Girls Branch), Cairo, Egypt.
**Microbiology Department, Soils; Water and Environment Research Institute, Agriculture Research Center, Giza, Egypt.
*Corresponding Author’s Email: elmonaliza96@gmail.com
Accepted 10 April, 2016
Abstract
Twenty-six bacterial and four algal isolates were isolated from rhizosphere of rice and sugar beet plants, grown in saline soil in Sahl El-Hussinian Station, El-Sharkia Governorate, Egypt and in vitro screening was done for different plant growth promotion activities i. e. indole acetic acid (IAA), gibberellic acid (GA) and carbohydrate production. Bio-control ability of bacterial isolates was screened by antagonistic activity against certain fungal pathogens. Results revealed that bacterial isolates No. 7 and 26 produced high amount of IAA (78.63 µg ml-1 and 78.73 µg ml-1, respectively), while isolate No. 5 was most potent isolate for GA (173.91 µg ml-1) and carbohydrate (187.18 µg ml-1) production. The active bacterial isolates (No. 5, 7, 26) in plant growth promoting substances production showed high antagonistic activity against certain pathogenic fungi (Fusarium sp. and Rhizoctonia sp.). Additionally, algal isolate No. 3 was active in production IAA (29.26 µg ml-1), while isolates No. 2 and 1 were efficient in GA (83.91 µg ml-1) and carbohydrate (178.81 µg ml-1) production, respectively. The most efficient rhizobacterial isolates (No. 5, 7 and 26) were selected and identified using Bio-log technique and 16S rRNA as Bacillus subtilis and Pseudomonas aeruginosa, respectively. Based on 16S rRNA sequence analysis both bacterial isolates (No. 7 and 26) identified as Pseudomonas aeruginosa. The most potent algal isolates (No. 1, 2 and 3) for plant growth promoting substances production were chosen and identified according to classical morphological characters as Anabaena sp., Nostoc muscorum and Anabaena variabilis, respectively. The optimum incubation period for highest production of IAA and GA by efficient bacterial and algal isolates was three and twenty days, respectively, while highest carbohydrate production was obtained after four and twenty five days, respectively.
Keywords: Soil salinity, Isolation, Purification, Identification, Phytohormones, Carbohydrate, Biocontrol, incubation periods.