Evidence for horizontal transfer of 1-aminocyclopropane-1-carboxylate deaminase genes.
Ontology highlight
ABSTRACT:
SUBMITTER: Hontzeas N
PROVIDER: S-EPMC1287689 | biostudies-literature | 2005 Nov
REPOSITORIES: biostudies-literature
Publications
Evidence for horizontal transfer of 1-aminocyclopropane-1-carboxylate deaminase genes.
Hontzeas N N Richardson A O AO Belimov A A Safronova V V Abu-Omar M M MM Glick B R BR
Applied and environmental microbiology 20051101 11
PCR was used to rapidly identify and isolate 1-aminocyclopropane-1-carboxylate (ACC) deaminase genes from bacteria. The Shimodaira-Hasegawa test was used to assess whether phylogenetically anomalous gene placements suggestive of horizontal gene transfer (HGT) were significantly favored over vertical transmission. The best maximum likelihood (ML) ACC deaminase tree was significantly more likely than four alternative ML trees, suggesting HGT. ...[more]
Similar Datasets
Project description:BackgroundComplex plant-microbe interactions have been established throughout evolutionary time, many of them with beneficial effects on the host in terms of plant growth, nutrition, or health. Some of the corresponding modes of action involve a modulation of plant hormonal balance, such as the deamination of the ethylene precursor 1-aminocyclopropane-1-carboxylate (ACC). Despite its ecological importance, our understanding of ACC deamination is impaired by a lack of direct molecular tools. Here, we developed PCR primers to quantify the ACC deaminase gene acdS and its mRNA in soil communities and assessed acdS+ microorganisms colonizing maize and other Poaceae species.ResultsEffective acdS primers suitable for soil microbial communities were obtained, enabling recovery of bona fida acdS genes and transcripts of diverse genetic backgrounds. High numbers of acdS genes and transcripts were evidenced in the rhizosphere of Poaceae, and numbers fluctuated according to plant genotype. Illumina sequencing revealed taxonomic specificities of acdS+ microorganisms according to plant host. The phylogenetic distance between Poaceae genotypes correlated with acdS transcript numbers, but not with acdS gene numbers or the genetic distance between acdS functional groups.ConclusionThe development of acdS primers enabled the first direct analysis of ACC deaminase functional group in soil and showed that plant ability to interact with soil-inhabiting acdS+ microorganisms could also involve particular plant traits unrelated to the evolutionary history of Poaceae species.
| S-EPMC6011333 | biostudies-literature
Project description:Growth in soil inoculated with plant growth promoting bacteria (PGPB) producing 1-aminocyclopropane-1-carboxylate |(ACC) deaminase or expressing of the corresponding acdS in transgenic lines reduces the decline in shoot length, shoot weight and photosynthetic capacity triggered by salt stress in Camelina sativa. Reducing the levels of stress ethylene decreases the expression of salt stress-responsive genes, specifically genes involved in development, senescence, chlorosis and leaf abscission that are highly induced by salt to the levels that may have a less negative effect on growth and productivity. Moderate expression of acdS under the promoter of the rolD promoter or growing plants in soil treated with the PGPB Pseudomonas migulae 8R6, were more effective in eliminating the expression of the genes involved in ethylene production and/or signaling than expression under the more active Cauliflower Mosaic Virus 35S promoter.
2019-06-13 | GSE132600 | GEO
Project description:Ethylene inhibits nodulation in various legumes. In order to investigate strategies employed by Rhizobium to regulate nodulation, the 1-aminocyclopropane-1-carboxylate (ACC) deaminase gene was isolated and characterized from one of the ACC deaminase-producing rhizobia, Rhizobium leguminosarum bv. viciae 128C53K. ACC deaminase degrades ACC, the immediate precursor of ethylene in higher plants. Through the action of this enzyme, ACC deaminase-containing bacteria can reduce ethylene biosynthesis in plants. Insertion mutants with mutations in the rhizobial ACC deaminase gene (acdS) and its regulatory gene, a leucine-responsive regulatory protein-like gene (lrpL), were constructed and tested to determine their abilities to nodulate Pisum sativum L. cv. Sparkle (pea). Both mutants, neither of which synthesized ACC deaminase, showed decreased nodulation efficiency compared to that of the parental strain. Our results suggest that ACC deaminase in R. leguminosarum bv. viciae 128C53K enhances the nodulation of P. sativum L. cv. Sparkle, likely by modulating ethylene levels in the plant roots during the early stages of nodule development. ACC deaminase might be the second described strategy utilized by Rhizobium to promote nodulation by adjusting ethylene levels in legumes.
| S-EPMC169147 | biostudies-literature
Project description:The main objective of this work is the study of the phylogeny, evolution and ecological importance of the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, the activity of which represents one of the most important and studied mechanisms used by plant growth-promoting microorganisms. The ACC deaminase gene and its regulatory elements presence in completely sequenced organisms was verified by multiple searches in diverse databases, and based on the data obtained a comprehensive analysis was conducted. Strain habitat, origin and ACC deaminase activity were taken into account when analyzing the results. In order to unveil ACC deaminase origin, evolution and relationships with other closely related pyridoxal phosphate (PLP) dependent enzymes a phylogenetic analysis was also performed. The data obtained show that ACC deaminase is mostly prevalent in some Bacteria, Fungi and members of Stramenopiles. Contrary to previous reports, we show that ACC deaminase genes are predominantly vertically inherited in various bacterial and fungal classes. Still, results suggest a considerable degree of horizontal gene transfer events, including interkingdom transfer events. A model for ACC deaminase origin and evolution is also proposed. This study also confirms the previous reports suggesting that the Lrp-like regulatory protein AcdR is a common mechanism regulating ACC deaminase expression in Proteobacteria, however, we also show that other regulatory mechanisms may be present in some Proteobacteria and other bacterial phyla. In this study we provide a more complete view of the role for ACC deaminase than was previously available. The results show that ACC deaminase may not only be related to plant growth promotion abilities, but may also play multiple roles in microorganism's developmental processes. Hence, exploring the origin and functioning of this enzyme may be the key in a variety of important agricultural and biotechnological applications.
| S-EPMC4048297 | biostudies-literature
Project description:Agrobacterium-mediated transformation is a useful tool for the genetic modification in plants, although its efficiency is low for several plant species. Agrobacterium-mediated transformation has three major steps in laboratory-controlled experiments: the delivery of T-DNA into plant cells, the selection of transformed plant cells, and the regeneration of whole plants from the selected cells. Each of these steps must be optimized to improve the efficiency of Agrobacterium-mediated plant transformation. It has been reported that increasing the number of cells transformed by T-DNA delivery can improve the frequency of stable transformation. Previously, we demonstrated that a reduction in ethylene production by plant cells during cocultivation with A. tumefaciens-expressing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase resulted in increased T-DNA delivery into the plant cells. In this study, to further improve T-DNA delivery by A. tumefaciens, we modified the expression cassette of the ACC deaminase gene using vir gene promoter sequences. The ACC deaminase gene driven by the virD1 promoter was expressed at a higher level, resulting in a higher ACC deaminase activity in this A. tumefaciens strain than in the strain with the lac promoter used in a previous study. The newly developed A. tumefaciens strain improves the delivery of T-DNA into Solanum lycopersicum (tomato) and Erianthus ravennae plants and thus may be a powerful tool for the Agrobacterium-mediated genetic engineering of plants.
| S-EPMC3831647 | biostudies-literature
Project description:1-Aminocyclopropane-1-carboxylic acid (ACC) deaminase (ACCD) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that cleaves the cyclopropane ring of ACC, to give ?-ketobutyric acid and ammonia as products. The cleavage of the C(?)-C(?) bond of an amino acid substrate is a rare event in PLP-dependent enzyme catalysis. Potential chemical mechanisms involving nucleophile- or acid-catalyzed cyclopropane ring opening have been proposed for the unusual transformation catalyzed by ACCD, but the actual mode of cyclopropane ring cleavage remains obscure. In this report, we aim to elucidate the mechanistic features of ACCD catalysis by investigating the kinetic properties of ACCD from Pseudomonas sp. ACP and several of its mutant enzymes. Our studies suggest that the pK(a) of the conserved active site residue, Tyr294, is lowered by a hydrogen bonding interaction with a second conserved residue, Tyr268. This allows Tyr294 to deprotonate the incoming amino group of ACC to initiate the aldimine exchange reaction between ACC and the PLP coenzyme and also likely helps to activate Tyr294 for a role as a nucleophile to attack and cleave the cyclopropane ring of the substrate. In addition, solvent kinetic isotope effect (KIE), proton inventory, and (13)C KIE studies of the wild type enzyme suggest that the C(?)-C(?) bond cleavage step in the chemical mechanism is at least partially rate-limiting under k(cat)/K(m) conditions and is likely preceded in the mechanism by a partially rate-limiting step involving the conversion of a stable gem-diamine intermediate into a reactive external aldimine intermediate that is poised for cyclopropane ring cleavage. When viewed within the context of previous mechanistic and structural studies of ACCD enzymes, our studies are most consistent with a mode of cyclopropane ring cleavage involving nucleophilic catalysis by Tyr294.
| S-EPMC3059330 | biostudies-literature
Project description:Plant growth-promoting rhizobacteria (PGPRs) that produce 1-aminocyclopropane-1-carboxylate (ACC) deaminase are capable of reducing limits to plant growth due to water-deficient conditions. Here, seven PGPR strains that can produce ACC deaminase were successfully obtained from the rhizosphere soil of grapevine (Vitis vinifera L.) in arid regions of China. The strains belonged to three different genera: Pseudomonas, Enterobacter, and Achromobacter, according to their 16S rDNA sequencing analysis. A drought tolerance experiment revealed two PGPR strains (DR3 and DR6) with exceptionally high phosphate solubilization, nitrogen fixation, indoleacetic acid (IAA), and exopolysaccharides secretion potential. Both strains were selected for use in a pot experiment to evaluate their growth-promoting effects on grapevines under drought conditions. Each of these two PGPRs and their mixed inoculation into grapevines were expected to alleviate the comprehensive growth inhibition of grapevines caused by drought stress. The mixed inoculation was hypothesized to elicit the best growth-promoting effects. Inoculation with the PGPRs not only enhanced the root-adhering soil/root tissue ratios and soil aggregate stability, but it also increased the nitrogen and phosphorus levels in the soil and plant leaves. Further, inoculation with PGPRs significantly altered the plant height, biomass of shoot and root organs, relative water contents, and net photosynthetic rate of leaves, enabling grapevines to better cope with drought. Moreover, the contents of IAA, abscisic acid, and malondialdehyde in these grapevines under drought stress were significantly changed by PGPRs. They indirectly affected biochemical and physiological properties of grapevines to alleviate their drought stress. Taken together, these results demonstrate that the DR3 and DR6 PGPRs might be useful for effectively weakening the growth inhibition caused by drought in grapevines. The strains might also be applied as effective bioinoculants to maintain the quality of wine grapes.
| S-EPMC10305780 | biostudies-literature
Project description:The genus Burkholderia includes pathogens of plants and animals and some human opportunistic pathogens, such as the Burkholderia cepacia complex (Bcc), but most species are nonpathogenic, plant associated, and rhizospheric or endophytic. Since rhizobacteria expressing ACC (1-aminocyclopropane-1-carboxylate) deaminase may enhance plant growth by lowering plant ethylene levels, in this work we investigated the presence of ACC deaminase activity and the acdS gene in 45 strains, most of which are plant associated, representing 20 well-known Burkholderia species. The results demonstrated that ACC deaminase activity is a widespread feature in the genus Burkholderia, since 18 species exhibited ACC deaminase activities in the range from 2 to 15 mumol of alpha-ketobutyrate/h/mg protein, which suggests that these species may be able to modulate ethylene levels and enhance plant growth. In these 18 Burkholderia species the acdS gene sequences were highly conserved (76 to 99% identity). Phylogenetic analysis of acdS gene sequences in Burkholderia showed tight clustering of the Bcc species, which were clearly distinct from diazotrophic plant-associated Burkholderia species. In addition, an acdS knockout mutant of the N(2)-fixing bacterium Burkholderia unamae MTl-641(T) and a transcriptional acdSp-gusA fusion constructed in this strain showed that ACC deaminase could play an important role in promotion of the growth of tomato plants. The widespread ACC deaminase activity in Burkholderia species and the common association of these species with plants suggest that this genus could be a major contributor to plant growth under natural conditions.
| S-EPMC2765135 | biostudies-literature
Project description:Metagenomes derived from environmental microbiota encode a vast diversity of protein homologs. How this diversity impacts protein function can be explored through selection assays aimed to optimize function. While artificially generated gene sequence pools are typically used in selection assays, their usage may be limited because of technical or ethical reasons. Here, we investigate an alternative strategy, the use of soil microbial DNA as a starting point. We demonstrate this approach by optimizing the function of a widely occurring soil bacterial enzyme, 1-aminocyclopropane-1-carboxylate (ACC) deaminase. We identified a specific ACC deaminase domain region (ACCD-DR) that, when PCR amplified from the soil, produced a variant pool that we could swap into functional plasmids carrying ACC deaminase-encoding genes. Functional clones of ACC deaminase were selected for in a competition assay based on their capacity to provide nitrogen to Escherichia coli in vitro. The most successful ACCD-DR variants were identified after multiple rounds of selection by sequence analysis. We observed that previously identified essential active-site residues were fixed in the original unselected library and that additional residues went to fixation after selection. We identified a divergent essential residue whose presence hints at the possible use of alternative substrates and a cluster of neutral residues that did not influence ACCD performance. Using an artificial ACCD-DR variant library generated by DNA oligomer synthesis, we validated the same fixation patterns. Our study demonstrates that soil metagenomes are useful starting pools of protein-coding-gene diversity that can be utilized for protein optimization and functional characterization when synthetic libraries are not appropriate.
| S-EPMC4751833 | biostudies-literature
Project description:Sinorhizobium sp. BL3 forms symbiotic interactions with mung bean (Vigna radiata) and contains lrpL-acdS genes, which encode the 1-aminocyclopropane-1-carboxylate (ACC) deaminase enzyme that cleaves ACC, a precursor of plant ethylene synthesis. Since ethylene interferes with nodule formation in some legumes and plays a role in senescence in plant cells, BL3-enhancing ACC deaminase activity (BL3(+)) and defective mutant (BL3(-)) strains were constructed in order to investigate the effects of this enzyme on symbiosis and nodule senescence. Nodulation competitiveness was weaker in BL3(-) than in the wild-type, but was stronger in BL3(+). The inoculation of BL3(-) into mung bean resulted in less plant growth, a lower nodule dry weight, and smaller nodule number than those in the wild-type, whereas the inoculation of BL3(+) had no marked effects. However, similar nitrogenase activity was observed with all treatments; it was strongly detected 3 weeks after the inoculation and gradually declined with time, indicating senescence. The rate of plant nodulation by BL3(+) increased in a time-dependent manner. Nodules occupied by BL3(-) formed smaller symbiosomes, and bacteroid degradation was more prominent than that in the wild-type 7 weeks after the inoculation. Changes in biochemical molecules during nodulation were tracked by Fourier Transform Infrared (FT-IR) microspectroscopy, and the results obtained confirmed that aging processes differed in nodules occupied by BL3 and BL3(-). This is the first study to show the possible role of ACC deaminase activity in senescence in determinate nodules. Our results suggest that an increase in ACC deaminase activity in this strain does not extend the lifespan of nodules, whereas the lack of this activity may accelerate nodule senescence.
| S-EPMC4676554 | biostudies-literature