Effect of IAA produced by Pseudomonas aeruginosa 6a (bc4) on seed germination and plant growth of Glycin max

Abstract

The expansion of organic agriculture has increased the demand for alternatives to chemical fertilizers and pesticides. Compared with non-rhizospheric, bacteria from rhizosphere are likely to synthesize and release auxins as secondary metabolites because of ambient supplies of substrate exuded from the roots. In the present study ability of Pseudomonas aeruginosa 6A (bc4) to produce IAA and stimulate the growth of Glycine max (JS-335) plant was determined by pot culture assay. Results showed early germination of seeds (2 days) as compared to uninoculated seeds (4 days). Further, increase in the germination percent, shoot and root length of treated soyabean plant as compared with control was also reported. Analysis of leaves and soil samples were carried for the presence of micro and macro nutrient in inoculated pot and revealed that pot containing plant inoculated with test organism (PO) and plant inoculated with test organism and tryptophan (POT) showed significant increase in carbon, nitrogen, phosphorus and potassium, whereas leaves samples showed increase in nitrogen, phosphorus, iron and copper, when compared with the control (P). The chlorophyll estimation was carried out by using Arnon's method. High chlorophyll content was recorded in POT which contains tryptophan as a precursor of IAA synthesis pathway as compared to PO and control.

Phosphate Solubilizing Rhizobacteria Could Have a Stronger Influence on Wheat Root Traits and Aboveground Physiology Than Rhizosphere P Solubilization

“…Improvements in seedlings root morphological traits in response to inoculation (specifically PSB 1 and PSB 4 ) were probably a consequence of a higher IAA production, which is a plant growth regulator hormone that in addition to boosting growth and root elongation, it also improves photosynthetic capacity, carbohydrate metabolism and the overall plant yield (Li et al, 2019). In this context, a recent study by Marathe et al (2017) demonstrated the ability of an IAAproducing PSB strain (Pseudomonas aeruginosa) to stimulate 2 days earlier seed germination and increase both nutrients uptake (N, P, and K) and chlorophyll content (chl a and chl b). This is fully aligned with the current study's findings as well as a number of previous research investigations ( Khiangte and Lalfakzuala, 2011;Linu et al, 2019;Liu et al, 2019), although accurate quantitative analysis will be required to determine either the amount and the type of IAA likely responsible for root growth (Kowalczyk and Sandberg, 2001;Liu et al, 2012).…”