Analysis of the Propionate Metabolism in Bacillus subtilis during 3-Indolacetic Production

Abstract

The genera Bacillus belongs to the group of microorganisms that are known as plant growth-promoting bacteria, their metabolism has evolved to produce molecules that benefit the growth of the plant, and the production of 3-indole acetic acid (IAA) is part of its secondary metabolism. In this work, Bacillus subtilis was cultivated in a bioreactor to produce IAA using propionate and glucose as carbon sources in an M9-modified media; in both cases, tryptophan was added as a co-substrate. The yield of IAA using propionate is 17% higher compared to glucose. After 48 h of cultivation, the final concentration was 310 mg IAA/L using propionate and 230 mg IAA/L using glucose, with a concentration of 500 mg Trp/L. To gain more insight into propionate metabolism and its advantages, the genome-scale metabolic model of B. subtilis (iBSU 1147) and computational analysis were used to calculate flux distribution and evaluate the metabolic capabilities to produce IAA using propionate. The metabolic fluxes demonstrate that propionate uptake favors the production of precursors needed for the synthesis of the hormone, and the sensitivity analysis shows that the control of a specific growth rate has a positive impact on the production of IAA.

Growth Enhancement of Tomato by a Plant Growth Promoting Bacterium, Bacillus subtilis PE7

“…Moreover, the viable cells of strain PE7 in the broth culture might also partially involve in growth promotion of tomato plants because our in vitro IAA and ammonia assays revealed that strain PE7 possessed the capacity to produce IAA and ammonia. Bacterial IAA plays a major role in root stimulation, cell division and enlargement, and enhances root development including root elongation and abundant formation of root hairs, thereby improving water and nutrient acquisition by plant root (Bessai et al, 2022;Castillo-Alfonso et al, 2022). In addition, ammonia released by PGPB induces a direct stimulation of plant growth through nitrogen accumulation for shoot and root growth, and biomass production (Kouam et al, 2023).…”

Growth and Yield Response and Water Use Efficiency of Cotton under Film-Mulched Drip Irrigation to Magnetized Ionized Water and Bacillus subtilis in Saline Soil in Xinjiang

“…In the 1-21-day period (budding stage), the average growth rate of LAI for each treatment in 2021 and 2022 was 0.02-0.09 d −1 , while in the 22-49-day period (budding stage to flowering stage), the corresponding value was 0.02-0.05 d −1 . Compared with B0, M increased the average growth rate of LAI during the 1-21-day period by 64 This study then analyzed the LAI on the 49th day after the first irrigation. Significant effects were exerted by irrigation water type and the B. subtilis amounts on LAI in the saline soil (p < 0.01).…”

“…This is a key reason explaining the inhibition of crop growth in saline soil. In order to address the effects of saline stress, the promotion of crop growth by B. subtilis is twofold [63,64]. Firstly, B. subtilis can alleviate the adverse effects of soil water and salt stress on crops.…”