Related Experiment Video
Updated: Apr 30, 2026

Generation of Composite Plants in Medicago truncatula used for Nodulation Assays
Published on: March 27, 2011
Modulation of endogenous indole-3-acetic acid biosynthesis in bacteroids within Medicago sativa nodules
C Bianco1, B Senatore1, S Arbucci2
1Institute of Biosciences and BioResources, Naples, Italy.
Abstract:
To evaluate the dose-response effects of endogenous indole-3-acetic acid (IAA) on Medicago plant growth and dry weight production, we increased the synthesis of IAA in both free-living and symbiosis-stage rhizobial bacteroids during Rhizobium-legume symbiosis. For this purpose, site-directed mutagenesis was applied to modify an 85-bp promoter sequence, driving the expression of iaaM and tms2 genes for IAA biosynthesis. A positive correlation was found between the higher expression of IAA biosynthetic genes in free-living bacteria and the increased production of IAA under both free-living and symbiotic conditions. Plants nodulated by RD65 and RD66 strains, synthetizing the highest IAA concentration, showed a significant (up to 73%) increase in the shoot fresh weight and upregulation of nitrogenase gene, nifH, compared to plants nodulated by the wild-type strain. When these plants were analyzed by confocal microscopy, using an anti-IAA antibody, the strongest signal was observed in bacteroids of Medicago sativa RD66 (Ms-RD66) plants, even when they were located in the senescent nodule zone. We show here a simple system to modulate endogenous IAA biosynthesis in bacteria nodulating legumes suitable to investigate which is the maximum level of IAA biosynthesis, resulting in the maximal increase of plant growth.
More Related Videos
20:01Single-plant, Sterile Microcosms for Nodulation and Growth of the Legume Plant Medicago truncatula with the Rhizobial Symbiont Sinorhizobium meliloti
Published on: October 1, 2013
10:58Plant Promoter Analysis: Identification and Characterization of Root Nodule Specific Promoter in the Common Bean
Published on: December 23, 2017
Related Concept Videos
Microbe-Plant Interactions
Gene Regulation in Microbial Communities: Quorum Sensing
Biosynthesis in Bacteria
Overview of Metabolism
Plant Metabolism
Sunlight, the primary source of energy in plants, is first absorbed by the chlorophyll pigments present in their leaves. Plants then use this energy to carry out photosynthesis, where water is oxidized into oxygen and carbon dioxide...
Bacterial Signaling
The Roles of Bacteria and Fungi in Plant Nutrition