Coronatine synthesis essay - Owen Catering

Genes responsible for coronatine synthesis in …

Coronatine synthesis essay - Downton Abbey Cooks

The phytotoxin coronatine (COR) is a functional mimic of the active plant hormone (+)-7--jasmonoyl--isoleucine (JA-IIe), which regulates stress responses. Structurally, COR is composed of a core unit, coronafacic acid (CFA), which is connected to coronamic acid (CMA), via an amide linkage. COR has been found to induce a range of biological activity in plants and based on its biological profile, COR, as well as CFA, and CMA are attractive starting points for agrochemical discovery, resulting in numerous total synthesis efforts. This review will discuss the synthetic approaches towards CFA, CMA and, ultimately COR, to date.1 Introduction2 Total Synthesis of Coronafacic Acid (CFA, )2.1 Mapping Synthetic Strategies2.2 Intermolecular Diels–Alder Approaches2.3 Intramolecular Diels–Alder Approaches2.4 Conjugate Addition Approaches2.5 Haller–Bauer Approaches2.6 Intramolecular Cyclisation Approaches2.7 Oxy-Cope Approaches3 Total Synthesis of Coronamic Acid (CMA, )3.1 Mapping Synthetic Strategies3.2 Final Installation of C1 3.3 Final Installation of C2 3.4 Final Installation of C3 4 Total Synthesis of Coronatine (COR, )5 Conclusions

Coronatine synthesis essay - TyTix, LLC

The phytotoxin coronatine (COR) is a functional mimic of the active plant hormone (+)-7--jasmonoyl--isoleucine (JA-IIe), which regulates stress responses. Structurally, COR is composed of a core unit, coronafacic acid (CFA), which is connected to coronamic acid (CMA), via an amide linkage. COR has been found to induce a range of biological activity in plants and based on its biological profile, COR, as well as CFA, and CMA are attractive starting points for agrochemical discovery, resulting in numerous total synthesis efforts. This review will discuss the synthetic approaches towards CFA, CMA and, ultimately COR, to date.

Coronatine is a chlorosis-inducing toxin produced by the plant pathogen Pseudomonas syringae pv atropurpurea. This bacterium is the causal agent of chocolate spot disease, in which brown lesions with chlorotic margins develop on the leaves of Lolium multiflorum Lam. Among the many physiological changes to plants caused by coronatine is the stimulation of ethylene production from bean leaves. The ethyl-substituted side chain of coronatine is an analog of the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC). We have examined the question of whether part or all of the released ethylene comes from the breakdown of coronatine itself. The rate of ethylene release from leaves of Nicotiana tabacum was proportional to the concentration of coronatine applied to the leaf surface. The lowest effective concentration of coronatine, applied to leaves at 15 pmol cm-2 of leaf cm-2 over a period of 4 h. The maximum rate of ethylene production occurred 28 to 32 h after application of coronatine. The specific activity of ethylene produced by discs cut from coronatine-treated Nicotiana tabacum leaves floating on a solution containing 10 mM [U-`4C]methionine was consistent with its exclusive origin from methionine. ACC accumulated in the coronatine-treated tissue. ACC synthase activity increased in Phaseolus aureus hypocotyls during a 6-h treatment with coronatine. Thus, coronatine induces the synthesis of ethylene from methionine.


Investigations of Coronatine Biosynthesis. Elucidation …

The phytopathogen Pseudomonas syringae produces the phytotoxin coronatine (COR) as a major virulence factor. COR and its precursor, coronafacic acid, function as molecular mimics of the plant signaling molecule jasmonate. A 32.8-kb plasmid-borne gene cluster mediates COR biosynthesis, which is optimal at 18 C and nondetectable at 28 C, the optimal growth temperature for P. syringae. The thermoregulation is mediated at the transcriptional level by an unconventional two-component regulatory system consisting of a histidine protein kinase, CorS, and two transcriptional activators, CorR and CorP. Dissection of this regulatory triad revealed that CorR binds to its target sequences in a thermoresponsive manner and that its DNA-binding activity is controlled by CorS. A Preliminary model for thermo-sensing by CorS is proposed based on its membrane topology and the analysis of translational fusions of CorS to reporter enzymes at different temperatures. CorP lacks a typical helix-turn-helix motif but possibly functions as a modulator of CorR or CorS activity. The thermoregulation of COR biosynthetic genes is widespread among various COR-producing P. syringae strains. Post-translational processes also contribute to the thermo-responsiveness of COR production. Additionally, COR synthesis in P. syringae is influenced by nutrient availability, rpoN encoding the alternative sigma factor s 54, and HrpV, a negative regulator of hrp gene expression, suggesting a complex regulatory network governing phytotoxin synthesis.

Coronatine synthesis essay - Steffie Beltt

An asymmetric total synthesis of (+)-coronafacic acid, starting from (R)-(+)-4-acetoxy-2-cyclopen-1-one as a chiral source, was accomplished. Construction of the 1-hydrindanone framework was carried out by using intramolecular 1, 6-conjugate addition as the key step. Coupling between (+)-coronafacic acid and protected coronamic acid, and subsequent deprotection provided (+)-coronatine. This is the first asymmetric total synthesis of (+)-coronatine.

This is the first asymmetric total synthesis of (+)- coronatine

An asymmetric total synthesis of (+)-coronafacic acid, starting from (R)-(+)-4-acetoxy-2-cyclopen-1-one as a chiral source, was accomplished. Construction of the 1-hydrindanone framework was carried out by using intramolecular 1, 6-conjugate addition as the key step. Coupling between (+)-coronafacic acid and protected coronamic acid, and subsequent deprotection provided (+)-coronatine. This is the first asymmetric total synthesis of (+)-coronatine.