International Journal of Agriculture, Environment & Biotechnology

Citation: IJAEB: 7(4): 747-757 December 2014

DOI Number: 10.5958/2230-732X.2014.01383.7

©2014 New Delhi Publishers. All rights reserved

GENETICS AND PLANT BREEDING

In vitro evaluation of plant growth regulators on tissue

culture bioassay produced by Pseudomonas species

Shweta Sharma* 1 , Mohinder Kaur 1 , Dinesh Kumar Srivastva 2 and

Geetika Gambhir 2

1 Department of Basic Science (Microbiology), Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni-Solan-173230, India.

2 Department of Biotechnology, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni-Solan-173230, India.

*Corresponding author: Shweta_85sharma@rediffmail.com

Paper No. 264

Received: 10 July, 2014

Accepted: 15 November, 2014

Published: 18 December, 2014

Abstract

Fluorescent Pseudomonas sp. is emerging as largest and potentially most promising group of PGPR

(plant growth promoting rhizobacteria) that are involved in plant growth enhancement. Plant growth

regulators viz., auxins, cytokinins and gibberellins help in plant growth and development. In present

study, fluorescent Pseudomonas strains isolated from rhizospheric soil from temperate fruit zone of

Himachal Pradesh were investigated for plant growth regulator production i.e. auxins, gibberellins and

cytokinins in nutrient broth. All the strains tested produced plant growth regulators in concentrations

auxins (1.83-21μg/ml), gibberellins (116.1-485.8μg/ml) and cytokinins (45.4-295.4μg/ml). Two strains

(An-1-kul and An-13-kul) were selected on the basis of over all PGPR activities for production of growth

regulators. Molecular characterization of best selected Pseudomonas strains were done by 16S-rRNA

technique. Plant growth regulators produced by best isolates were further studied to observe their effect

on growth of callus formation, shoot formation of broccoli and root elongation of cabbage

Highlights

In recent study we evaluated that partially purified cytokinins and auxins extracted from Pseudomonas

aeruginosa showed maximum callus formation and shoots regeneration in broccoli cotyledon explants in

vitro developed shoots and development of roots at concentration of 2.0mg/l.

Keywords: Plant growth regulators, auxins, gibberellins, cytokinins, PGPR, Callus formation, root

elongation.

Fluorescent Pseudomonads are considered to

of temperate fruit growing zone (apple and pear

promote plant growth directly and indirectly and

orchards) appear to have greater potential to

kept under plant growth promoting rhizobacteria

synthesize and release auxins, gibberellins and

(PGPR) group. PGPR can exhibit a variety of

cytokinins as secondary metabolites and these are

characteristics responsible for influencing plant

responsible for pronounced effect on plant growth

growth. The common traits include production

and development. Plant growth regulators are the

of plant growth regulators (auxins, gibberellins,

organic substances that influence physiological

cytokinins etc.), siderophore, HCN and antibiotics

processes of plants at very low concentrations

( Arshad and Frankenberger, 1992; Ahad et al.,

when produced endogenously by plants, they are

2012). Microorganism isolated from the rhizosphere

referred to as phytohormones (plant hormones),