07-08-2013, 01:17 PM
Plant Growth-Promoting Rhizobacteria: Potential Green Alternative for Reducing Incidence of Tomato Leaf Curl Virus
ABSTRACT
Pathogenic micro-organisms affecting plant health are major and chronic threat to food production. Increasing use of chemical inputs causes several negative effects like development of resistance in pathogen to applied agents and their non-target environmental impacts. Thus, biological control through the use of plant growth promoting rhizobacteria (PGPR) is being considered as an alternative way of reducing the use of chemicals in agriculture. In present study, fifteen isolates of Pseudomonas were evaluated for their ability to improve plant defence against tomato leaf curl viral (ToLCV) disease in tomato. Pseudomonas spp. is well known for their ability to improve plant growth through different direct and indirect mechanisms like phosphate solubilization, secretion of plant growth hormones, supresses plant pathogen etc. Bio-formulations of Pseudomonas isolates were applied by seed priming, soil application and foliar application to tomato plants at fifteen days interval and plants were infected with ToLCV. It was found that isolate 139, 360(2) and 326(4) could potentially reduce virus disease up to 10%, 30% and 40% respectively at 45 D.A.I also enhance plant growth compared with control plants. Isolate 352(1), 309(2), 396(4) and 218(1) were similar to control plants with respect to plant growth performance but very efficient in controlling ToLCV (disease incidence was 10-20% at 45 DAI). Understanding the mechanisms of plant growth promotion and disease control by such PGPR isolates expected to provide a greater insight for the multiple facets of disease suppression.