Cereals can trap endophytic bacteria with potential beneficial traits when grown ex-situ in harsh soils.

Microbial communities associated with plants growing in harsh conditions, including salinity and water deficiency, have developed adaptive features which permit them to grow and survive under extreme environmental conditions. In the present study, an ex-situ plant trapping method has been applied to collect the culturable microbial diversity associated with the soil from harsh and remote areas. Oryza sativa cv.

Drought responsiveness in six wheat genotypes: identification of stress resistance indicators.

Introduction: Wheat ( L.) is among the world's most important staple food crops. In the current climate change scenario, a better understanding of wheat response mechanisms to water stress could help to enhance its productivity in arid ecosystems.

Exploitation of Plant Growth Promoting Bacteria for Sustainable Agriculture: Hierarchical Approach to Link Laboratory and Field Experiments.

To feed a world population, which will reach 9.7 billion in 2050, agricultural production will have to increase by 35-56%. Therefore, more food is urgently needed.

Endophytes from African Rice ( L.) Efficiently Colonize Asian Rice ( L.) Stimulating the Activity of Its Antioxidant Enzymes and Increasing the Content of Nitrogen, Carbon, and Chlorophyll.

Bacterial endophytes support the adaptation of host plants to harsh environments. In this study, culturable bacterial endophytes were isolated from the African rice L., which is well-adapted to grow with poor external inputs in the tropical region of Mali.

Molecular and physiological analysis of indole-3-acetic acid degradation in Bradyrhizobium japonicum E109.

Bradyrhizobium japonicum E109 is a bacterium widely used for inoculants production in Argentina. It is known for its ability to produce several phytohormones and degrade indole-3-acetic acid (IAA). The genome sequence of B.

Bacterial IAA-Delivery into Medicago Root Nodules Triggers a Balanced Stimulation of C and N Metabolism Leading to a Biomass Increase.

Indole-3-acetic acid (IAA) is the main auxin acting as a phytohormone in many plant developmental processes. The ability to synthesize IAA is widely associated with plant growth-promoting rhizobacteria (PGPR). Several studies have been published on the potential application of PGPR to improve plant growth through the enhancement of their main metabolic processes.

New Insights into Structural and Functional Roles of Indole-3-acetic acid (IAA): Changes in DNA Topology and Gene Expression in Bacteria.

Indole-3-acetic acid (IAA) is a major plant hormone that affects many cellular processes in plants, bacteria, yeast, and human cells through still unknown mechanisms. In this study, we demonstrated that the IAA-treatment of two unrelated bacteria, the nsifer meliloti 1021 and coli, harboring two different host range plasmids, influences the supercoiled state of the two plasmid DNAs in vivo. Results obtained from in vitro assays show that IAA interacts with DNA, leading to DNA conformational changes commonly induced by intercalating agents.

Efficient colonization of the endophytes Herbaspirillum huttiense RCA24 and Enterobacter cloacae RCA25 influences the physiological parameters of Oryza sativa L. cv. Baldo rice.

Several important bacterial characteristics, such as biological nitrogen fixation, phosphate solubilization, 1-aminocyclopropane-1-carboxylate deaminase activity and production of siderophores and phytohormones, can be assessed as plant growth promotion traits. Our aim was to evaluate the effects of nitrogen fixing and indole-3-acetic acid (IAA) producing endophytes in two Oryza sativa cultivars (Baldo and Vialone Nano). Three bacteria, Herbaspirillum huttiense RCA24, Enterobacter asburiae RCA23 and Staphylococcus sp.

Implementing an EU opt-in mechanism for GM crop cultivation.

A proposal for implementing an opt‐in mechanism that would allow individual member states of the EU to cultivate genetically modified crops on their territory. [Image: see text]

Improved Drought Stress Response in Alfalfa Plants Nodulated by an IAA Over-producing Strain.

The drought-stress response in plant involves the cross-talk between abscisic acid (ABA) and other phytohormones, such as jasmonates and ethylene. The auxin indole-3-acetic acid (IAA) plays an integral part in plant adaptation to drought stress. Investigation was made to see how the main auxin IAA interacted with other plant hormones under water stress, applied through two different growth conditions (solid and hydroponic).

The Overproduction of Indole-3-Acetic Acid (IAA) in Endophytes Upregulates Nitrogen Fixation in Both Bacterial Cultures and Inoculated Rice Plants.

Endophytic bacteria from roots and leaves of rice plants were isolated and identified in order to select the diazotrophs and improve their nitrogen-fixing abilities. The nitrogen-fixing endophytes were identified by PCR amplification of the nifH gene fragment. For this purpose, two isolates, Enterobacter cloacae RCA25 and Klebsiella variicola RCA26, and two model bacteria (Herbaspirillum seropedicae z67 and Sinorhizobium fredii NGR234) were transformed to increase the biosynthesis of the main plant auxin indole-3-acetic acid (IAA).

Quantification of Triphenyl-2H-tetrazoliumchloride Reduction Activity in Bacterial Cells.

This protocol describes the use of the 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) salt to evaluate the cell redox potential of rhizobia cells. The production of brightly colored and insoluble 1,3,5-Triphenyltetrazolium formazan arising from TTC reduction is irreversible and can be easily quantified using a spectrophotometer. This protocol allows the production of reproducible results in a relatively short time for 1021 cells grown both in exponential and stationary phases.

Overproduction of Indole-3-Acetic Acid in Free-Living Rhizobia Induces Transcriptional Changes Resembling Those Occurring in Nodule Bacteroids.

Free-living bacteria grown under aerobic conditions were used to investigate, by next-generation RNA sequencing analysis, the transcriptional profiles of Sinorhizobium meliloti wild-type 1021 and its derivative, RD64, overproducing the main auxin indole-3-acetic acid (IAA). Among the upregulated genes in RD64 cells, we detected the main nitrogen-fixation regulator fixJ, the two intermediate regulators fixK and nifA, and several other genes known to be FixJ targets. The gene coding for the sigma factor RpoH1 and other genes involved in stress response, regulated in a RpoH1-dependent manner in S.

Bisphenol A removal by a Pseudomonas aeruginosa immobilized on granular activated carbon and operating in a fluidized bed reactor.

Serratia rubidiae, Pseudomonas aeruginosa and Escherichia coli K12 have been studied for their ability of Bisphenol A removal from aqueous systems and biofilm formation on activated granule carbon. Mathematical equations for biodegradation process have been elaborated and discussed. P.

Modulation of endogenous indole-3-acetic acid biosynthesis in bacteroids within Medicago sativa nodules.

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.

Auxins upregulate nif and fix genes.

In a recent publication we analyzed the global effects triggered by IAA overproduction in S. meliloti RD64 under free-living conditions by comparing the gene expression pattern of wild type 1021 with that of RD64 and 1021 treated with IAA and other four chemically or functionally related molecules. Among the genes differentially expressed in RD64 and IAA-treated 1021 cells we found two genes of pho operon, phoT and phoC.

Improvement of phosphate solubilization and Medicago plant yield by an indole-3-acetic acid-overproducing strain of Sinorhizobium meliloti.

Nitrogen (N) and phosphorus (P) are the most limiting factors for plant growth. Some microorganisms improve the uptake and availability of N and P, minimizing chemical fertilizer dependence. It has been published that the RD64 strain, a Sinorhizobium meliloti 1021 strain engineered to overproduce indole-3-acetic acid (IAA), showed improved nitrogen fixation ability compared to the wild-type 1021 strain.

Legumes like more IAA.

The improvement of the effectiveness and survival of rhizobia in the rhizosphere of legume host plants is a common practice in agricultural legume production. We have recently reported that the overexpression of IAA in S. meliloti 1021 played a positive role in the adaptation to various stress conditions both in free-living bacteria and in nodulated plants.

Medicago truncatula improves salt tolerance when nodulated by an indole-3-acetic acid-overproducing Sinorhizobium meliloti strain.

The abiotic stress resistance of wild-type Sinorhizobium meliloti 1021 was compared with that of RD64, a derivative of the 1021 strain harbouring an additional pathway for the synthesis of indole-3-acetic acid (IAA), expressed in both free-living bacteria and bacteroids. It is shown here that the IAA-overproducing RD64 strain accumulated a higher level of trehalose as its endogenous osmolyte and showed an increased tolerance to several stress conditions (55 degrees C, 4 degrees C, UV-irradiation, 0.5 M NaCl, and pH 3).

Effects of indole-3-acetic acid on Sinorhizobium meliloti survival and on symbiotic nitrogen fixation and stem dry weight production.

We evaluated the effects of the main auxin phytohormone, indole-3-acetic acid (IAA), on the central metabolism of Sinorhizobium meliloti 1021. We either treated S. meliloti 1021 wild-type cells with 0.

Introduction of a novel pathway for IAA biosynthesis to rhizobia alters vetch root nodule development.

We introduced into Rhizobium leguminosarum bv. viciae LPR1105 a new pathway for the biosynthesis of the auxin, indole-3-acetic acid (IAA), under the control of a stationary phase-activated promoter active both in free-living bacteria and bacteroids. The newly introduced genes are the iaaM gene from Pseudomonas savastanoi and the tms2 gene from Agrobacterium tumefaciens.

Indole-3-acetic acid regulates the central metabolic pathways in Escherichia coli.

The physiological changes induced by indoleacetic acid (IAA) treatment were investigated in the totally sequenced Escherichia coli K-12 MG1655. DNA macroarrays were used to measure the mRNA levels for all the 4290 E. coli protein-coding genes; 50 genes (1.