In Vitro Production of Growth Regulator (IAA) and Phosphatase by Phosphate Solubilizing Bacteria

Abstract

Abstract-The phosphate solubilizing bacteria (phosphobacteria) secrete organic acids and phosphatase enzymes which act on insoluble phosphates and convert the same into soluble forms thus providing available phosphorus to the plants. They are also known to produce amino acids, vitamins and growth promoting substance like indole acetic acid (IAA), which helps in better growth of plants. The present studyaimed to isolate and screen out phosphate solubilizing bacteria from soil rhizosphere using serial dilution technique on pikovskaya agar plate. An effort was also made to obtain bacterial isolates for producing phosphatase enzyme and to study the production of IAA in NBRIP media containing tryptophan as a substrate.A total of 17 strains were isolated from soil rhizosphere and all the strains were able to produce IAA and phosphatase enzyme in vitro condition.

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

“…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). However, it remains unclear why inoculation with PSB 3 that exhibit the highest IAA production rate did not affect root traits (especially A B FIGURE 4 | Correlations between total chlorophyll and plant P (inorganic (A) and total (B) content in durum wheat inoculated with five PSB isolates and fertilized with rock P (black circles) versus non-inoculated wheat fertilized with P (RP and TSP) treatment alone (grey squares).…”

Characterization of Plant Growth-Promoting Traits and Inoculation Effects on Triticum durum of Actinomycetes Isolates under Salt Stress Conditions

“…For IAA production, the spore suspension of each strain (100 µL) was inoculated in 5 mL of the National Botanical Research Institutes' phosphate growth medium (NBRIP) supplemented with tryptophan (0.2%) [36][37][38][39][40]. The broth cultures were kept to grow at 30 • C for 7 days at 150 rpm.…”