An expeditious preparation of all enantiopure diastereoisomers of aromatic A-ring analogues of strigolactones, germination stimulants for seeds of the parasitic weeds Striga and Orobanche

The structures of naturally occurring germination stimulants for seeds of the parasitic weeds Striga spp. and Orobanche spp. are described. The bioactiphore in this strigolactone family of stimulants is deduced from a structure-activity relationship and shown to reside in the CD part of the stimulant molecule. A molecular mechanism for the initial stages of seed germination is proposed. The influence of stereochemistry on the stimulant activity is significant. Combining this molecular information leads to a model for the design of synthetic strigolactones. Nijmegen-1 is a typical example of a highly active, newly designed synthetic stimulant. The occurrence of natural stimulants not belonging to the strigolactone family, such as cotylenin and parthenolide, is briefly described. The biosynthesis of natural strigolactones from beta-carotene is analysed in terms of isolated and predicted stimulants. This scheme will be helpful in the search for new strigolactones from root exudates. Protein fishing experiments to isolate and characterise the receptor protein using biotin-labelled GR 24 are described. A receptor protein of 60 kD was identified by this method. Nijmegen-1 has been tested as a suicidal germination agent in field trials on tobacco infested by Orobanche ramosa L. The preliminary results are highly rewarding. Finally, some future challenges in synthesis are described. These include synthesising new natural and synthetic stimulants and establishing the molecular connection between strigolactones as germination stimulants, as the branching factor for arbuscular mycorrhizal fungi and as an inhibitor of shoot branching.

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“…4). 43, 44 For 2′‐epi GR 24, i.e. ‘natural’ C 3a /C 8b and ‘unnatural’ C‐2′, and ent 2′‐epi GR 24, i.e.…”

Section: Stereochemistrymentioning

confidence: 99%

Structure and function of natural and synthetic signalling molecules in parasitic weed germination

Zwanenburg

Mwakaboko

Reizelman

et al. 2009

Pest Management Science

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220

192

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“…The introduction of a 4‐α‐hydroxyl group appears to increase the activity, in particular, in 2′‐epi‐strigolactones. For example, solanacol ( 11 ), 4‐α‐hydroxy‐5,8‐dimethyl‐GR24, is far more active than GR24,23 while the introduction of a methyl group at C‐6 or C‐8 did not affect germination stimulation activity 37…”

Section: Biological Activity Of Strigolactonesmentioning

confidence: 99%

Strigolactones: structures and biological activities

Yoneyama

Xie

Yoneyama

et al. 2009

Pest Management Science

164

118

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Strigolactones released from plant roots induce seed germination of root parasitic weeds, witchweeds (Striga spp.) and broomrapes (Orobanche spp.), and hyphal branching of symbiotic arbuscular mycorrhizal (AM) fungi. In addition to these functions in the rhizosphere, strigolactones have recently been shown to be a novel class of plant hormones regulating shoot outgrowth. The natural strigolactones identified so far have the common C-D ring moiety, which is thought to be the essential structure for exhibiting biological activity. The introduction of substitutions on the A-B ring moiety of 5-deoxystrigol, the basic strigolactone, affords various strigolactones, e.g. hydroxylation on C-4, C-5 and C-9 leads to orobanchol, strigol and sorgomol respectively. Then, acetylation and probably other derivatisations of these hydroxy-strigolactones would occur. Although the C-2'-(R) stereochemistry was thought to be an important structural feature for potent germination stimulation activity, 2'-epi-strigolactones were found in root exudates of tobacco, rice, pea and other plant species, indicating that at least some plants produce both epimers.

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“…The route using the Stobbe condensation has an attractive feature as it can be used to prepare a variety of dimethyl‐substituted GR24 analogues . A conventional approach to monomethyl‐substituted GR24 analogues was described, along with the separation of the racemates on a chiral HPLC column . The synthesis of enantiopure GR24 with strigol stereochemistry has received attention from various groups.…”

Section: Design Of Bioactive Sl Analoguesmentioning

confidence: 99%

“…49 A conventional approach to monomethyl-substituted GR24 analogues was described, along with the separation of the racemates on a chiral HPLC column. 53 The synthesis of enantiopure GR24 with strigol stereochemistry has received attention from various groups. The first method makes use of the homochiral D-ring synthon (cf.…”

Section: Gr24mentioning

confidence: 99%

Synthesis of strigolactones, a strategic account

Zwanenburg

Zeljković

Pospíšil

2015

Pest Management Science

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Strigolactones (SLs) constitute a new class of plant hormones that have received growing interest in recent years. They firstly became known as signalling molecules for host recognition by parasitic plants, and for symbiosis of plants with arbuscular mycorrhizal fungi. Furthermore, they are involved in numerous physiological processes in plants, such as the regulation of plant architecture and the response to abiotic factors. SLs are produced by plants in extremely low quantities, and they may be unstable during the purification process. Therefore, their total synthesis is highly relevant for confirming the structures assigned on the basis of spectroscopic and other physical data. A second important theme in SL research is the design and synthesis of SL analogues that have a simplified structure while still featuring the essential bioproperties. This review summarises the strategy and synthesis of naturally occurring SLs, and the design and synthesis of SL analogues with appreciable bioactivity.

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An expeditious preparation of all enantiopure diastereoisomers of aromatic A-ring analogues of strigolactones, germination stimulants for seeds of the parasitic weeds Striga and Orobanche

Cited by 17 publications

References 18 publications

Structure and function of natural and synthetic signalling molecules in parasitic weed germination

Structure and function of natural and synthetic signalling molecules in parasitic weed germination

Strigolactones: structures and biological activities

Synthesis of strigolactones, a strategic account

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