Participation of Auxin Transport in the Early Response of the Arabidopsis Root System to Inoculation with Azospirillum brasilense

Abstract

The potential of Plant Growth Promoting Rhizobacteria (PGPR) has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield. A. brasilense produces a wide variety of molecules, including the natural auxin indole-3-acetic acid (IAA), as well as other phytoregulators. However, several studies have suggested that auxin induces changes in plant development during their interaction with the bacteria. The effects of A. brasilense Sp245 on the development of Arabidopsis thaliana root were investigated to help explain the molecular basis of the interaction. The results obtained showed a decrease in primary root length from the first day and remained so throughout the exposure, accompanied by a stimulation of initiation and maturation of lateral root primordia and an increase of lateral roots. An enhanced auxin response was evident in the vascular tissue and lateral root meristems of inoculated plants. However, after five days of bacterization, the response disappeared in the primary root meristems. The role of polar auxin transport (PAT) in auxins relocation involved the PGP1, AXR4-1, and BEN2 proteins, which apparently mediated A. brasilense-induced root branching of Arabidopsis seedlings.

Progress in Microbial Fertilizer Regulation of Crop Growth and Soil Remediation Research

“…One study used Helicobacter Azotrophicus inoculation to examine the impacts of root development in Arabidopsis thaliana in Brazil. The findings indicated that the growth hormone encouraged the production of lateral root meristematic tissues [75].…”

Nanozinc and plant growth-promoting bacteria improve biochemical and metabolic attributes of maize in tropical Cerrado

“…In addition, PGPBs contribute to the synthesis of secondary metabolites, water absorption, nutrient [phosphorus (P), Zn, and potassium (K)] solubilization, and tolerance to biotic and abiotic stresses ( Hungria et al., 2018 ; Jalal et al., 2021 ; Lopes et al., 2021 ). The inoculants of the genus Azospirillum are being recognized in the biosynthesis of auxin synthesis, nutrient cycling and availability, and biological nitrogen (N) fixation by reducing N 2 into ammonia (NH 3 ) ( Bhat et al., 2019 ; Carrillo-Flores et al., 2022 ; Galindo et al., 2022 ). Bacillus subtilis ( B. subtilis ) has the ability to promote plant growth through P solubilization, increase Zn use efficiency, bioremediation of heavy metals, and controlling phytopathogenic infestation, which in turn leads to increased root–shoot development and productivity ( Lobo et al., 2019 ; dos Santos et al., 2021 ; Jalal et al., 2022a ).…”

Symbiotic Variations among Wheat Genotypes and Detection of Quantitative Trait Loci for Molecular Interaction with Auxin-Producing Azospirillum PGPR

“…This is particularly relevant when considering auxin-producing PGPR bacteria as they represent an important group of PGPR [ 4 , 15 ]. In this work, we address this issue with the α-proteobacterium Azospirillum baldaniorum (previously brasilense ) Sp245, a model PGPR strain in which the bacterial synthesis of indole-3-acetic acid (IAA) has been extensively studied [ 15 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ].…”