ABSTRACT Many plant-associated bacteria synthesize the phytohormone indoleacetic acid (IAA). While IAA produced by phytopathogenic bacteria, mainly indoleacetamide pathway, has been implicated in induction of plant tumors, it is not clear whether synthesized beneficial usually via indolepyruvic involved growth promotion. To determine bacterial enhances root development host plants, ipdc gene that encodes indolepyruvate decarboxylase, a key enzyme was isolated from growth-promoting bacterium...

In agricultural cropping systems, crop residues are sources of organic carbon (C), an important factor influencing denitrification. The effects red clover, soybean, and barley plant glucose on denitrifier abundance, denitrification gene mRNA levels, nitrous oxide (N(2)O) emissions, rates were quantified in anoxic soil microcosms for 72 h. nosZ abundances levels significantly increased response to all treatments over time. contrast, the abundance Pseudomonas mandelii closely related species...

Lands under riparian and agricultural management differ in soil properties, water content, plant species nutrient content are therefore expected to influence denitrifier communities, denitrification nitrous oxide (N(2) O) emissions. Denitrifier community abundance, structure, gene expression activity were quantified on three dates a maize field adjacent zone. N(2) O emissions greater the zone, whereas complete was In general, targeted abundance did not change between zones. However, nosZ...

The phytohormone indole-3-acetic acid (IAA) accumulates in the culture medium of plant growth-promoting bacterium Pseudomonas putida GR12-2 only when grown presence exogenous tryptophan, suggesting that expression indolepyruvate decarboxylase, a key enzyme IAA biosynthesis pathway this bacterium, may be regulated by tryptophan. To test hypothesis, we isolated promoter region for ipdc gene encoding decarboxylase inverse polymerase chain reaction (PCR) and inserted it upstream bioluminescent...

The plant growth-promoting rhizobacterium Enterobacter cloacae UW5 synthesizes the growth hormone indole-3-acetic acid (IAA) via indole-3-pyruvate pathway utilizing enzyme decarboxylase that is encoded by ipdC. In this bacterium, ipdC expression and IAA production occur in stationary phase are induced an exogenous source of tryptophan, conditions present rhizosphere. aim study was to identify regulatory protein controls We identified a sequence promoter region highly similar recognition for...

An antifreeze protein secreted to the growth medium by plant promoting rhizobacterium Pseudomonas putida GR12-2 was purified apparent homogeneity. The has a molecular mass of 164 ± 15 kDa and an isoelectric point 5.3, contains both carbohydrate lipid moieties, is relatively rich in glycine alanine. properties are similar previously reported for bacterial ice-nucleation proteins. In fact, also displays low level activity. Removal approximately 92 from 164-kDa glycoprotein did not noticeably...

RpoS is a conserved alternative sigma factor that regulates the expression of many stress response genes in Escherichia coli. The regulon large but has not yet been completely characterized. In this study, we report identification over 100 RpoS-dependent fusions genetic screen based on differential an operon-lacZ fusion bank rpoS mutant and wild-type backgrounds. Forty-eight independent gene were identified, including several well-characterized RpoS-regulated genes, such as osmY, katE, otsA....

Plant parasitic nematodes (PPNs) seriously threaten global food security. Conventionally an integrated approach to PPN management has relied heavily on carbamate, organophosphate and fumigant nematicides which are now being withdrawn over environmental health safety concerns. This progressive withdrawal left a significant shortcoming in our ability manage these economically important parasites, highlights the need for novel robust control methods. Nematodes can assimilate exogenous peptides...

As a means of investigating gene function, we developed robust transcription fusion reporter vector to measure expression in bacteria. The vector, pTH1522, was used construct random insert library for the Sinorhizobium meliloti genome. pTH1522 replicates Escherichia coli and can be transferred to, but cannot replicate in, S. meliloti. Homologous recombination DNA fragments cloned into genome generates transcriptional fusions either genes gfp(+) lacZ or gusA rfp, depending on orientation...

Environmental conditions can change dramatically over a crop season and among locations in an agricultural field increase denitrification emissions of the potent greenhouse gas nitrous oxide. In previous study, changes overall size denitrifier community potato were relatively small did not correlate with variations environmental or rates. However, denitrifying bacteria are taxonomically diverse, different members may respond differently to changes. The objective this research was understand...

Red band needle blight caused by Dothistroma septosporum and D. pini, brown spot Lecanosticta acicola provoke severe premature defoliation in Pinus, subsequent reduction of photosynthetic surfaces, vitality, growth young adult trees. The recurrent damage results branch tree death. Until recently, pine diseases have had only minor impacts on native exotic forest trees the North Spain, but past five years, these pathogen species spread widely mortality plantations Pinus locations where they...

Pitch canker, caused by the fungus Fusarium circinatum, is a major disease of Pinus radiata currently controlled to some extent in nurseries good hygiene and application synthetic fungicides. The aim this study was evaluate alternative strategies control fungal infections young pine plantations. antagonistic effects biocontrol bacteria essential oils against F. circinatum vitro P. trees were assessed. Pseudomonas fluorescens, Erwinia billingiae, Bacillus simplex reduced growth 17%–29%,...

We report the complete genome sequence of Enterobacter cloacae UW5, an indole-3-acetic acid-producing rhizobacterium originally isolated from rhizosphere grass. The 4.9-Mbp has a G+C content 54% and contains 4,496 protein-coding sequences.

Pseudomonas putida GR12-2 is well known as a plant growth-promoting rhizobacterium; however, phylogenetic analysis using the 16S rRNA gene and four housekeeping genes indicated that this strain forms monophyletic group with syringae complex, which composed of several species pathogens. On basis these sequence analyses, we suggest P. be redesignated GR12-2. To compare ecological roles its close relatives pathovar (pv.) tomato DC3000 pv. B728a, investigated their ability to cause disease...

The soil bacterium Enterobacter cloacae UW5 produces the rhizosphere signaling molecule indole-3-acetic acid (IAA) via indolepyruvate pathway. Expression of decarboxylase, a key pathway enzyme encoded by ipdC, is upregulated transcription factor TyrR in response to aromatic amino acids. Some members regulon may also be controlled branched-chain acids and here we show that expression from ipdC promoter production IAA are downregulated valine, leucine isoleucine. Regulation synthesis both...