BACKGROUND: Strigolactones (SLs) have a vast number of ecological implications because of the broad spectrum of their biological activities. Unfortunately, the limited availability of SLs restricts their applicability for the benefit of humanity and renders synthesis the only option for their production. However, the structural complexity of SLs impedes their economical synthesis, which is unfeasible on a large scale. Synthesis of SL analogues and mimics with a simpler structure, but with retention of bioactivity, is the solution to this problem. RESULTS: Here, we present eight new hybrid-type SL analogues derived from auxin, synthesized via coupling of auxin ester [ethyl 2-(1H-indol-3-yl)acetate] and of ethyl 2-phenylacetate with four D-rings (mono-, two di- and trimethylated). The new hybrid-type SL analogues were bioassayed to assess the germination activity of seeds of the parasitic weeds Striga hermonthica, Orobanche minor and Phelipanche ramosa using the classical method of counting germinated seeds and a colorimetric method. The bioassays revealed that analogues with a natural monomethylated D-ring had appreciable to good activity towards the three species and were the most active derivatives. By contrast, derivatives with the trimethylated D-ring showed no activity. The dimethylated derivatives (2,4-dimethyl and 3,4-dimethyl) were slightly active, especially towards P. ramosa. CONCLUSIONS: New hybrid-type analogues derived from auxins have been prepared. These analogues may be attractive as potential suicidal germination agents for parasitic weed control because of their ease of preparation and relevant bioactivity. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

• Klíčová slova
• auxins, strigolactone analogues, strigolactones, suicidal germination,
• MeSH
• klíčení účinky léků   MeSH
• kontrola plevele metody   MeSH
• kyseliny indoloctové chemie   MeSH
• laktony chemická syntéza   MeSH
• Orobanchaceae účinky léků   fyziologie   MeSH
• Orobanche účinky léků   fyziologie   MeSH
• plevel účinky léků   fyziologie   MeSH
• semena rostlinná účinky léků   fyziologie   MeSH
• Striga účinky léků   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kyseliny indoloctové MeSH
• laktony MeSH

BACKGROUND: Strigolactones are a unique class of plant metabolites which serve as a rhizosphere signal for parasitic plants and evocate their seed germination. The expansion of these parasitic weeds in the food crop fields urgently calls for their increased control and depletion. Simple strigolactone analogues able to stimulate seed germination of these parasitic plants may represent an efficient control measure through the induction of suicidal germination. RESULTS: Triazolide-type strigolactone mimics were easily synthesized in three steps from commercially available materials. These derivatives induced effectively seed germination of Phelipanche ramosa with EC50 as low as 5.2 × 10-10 M. These mimics did not induce seed germination of Striga hermonthica even at high concentration (≥1 × 10-5 M). CONCLUSIONS: Simple and stable strigolactone mimics with selective activity against Phelipanche ramosa were synthesized. © 2019 Society of Chemical Industry.

• Klíčová slova
• Arabidopsis, Phelipanche, Striga, seed germination, strigolactones,
• MeSH
• herbicidy chemická syntéza   farmakologie   MeSH
• klíčení účinky léků   MeSH
• laktony chemická syntéza   farmakologie   MeSH
• Orobanchaceae účinky léků   MeSH
• plevel účinky léků   MeSH
• semena rostlinná účinky léků   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• herbicidy MeSH
• laktony MeSH
• triazolide strigolactone MeSH Prohlížeč

Strigolactones are a particular class of plant metabolites with diverse biological functions starting from the stimulation of parasitic seed germination to phytohormonal activity. The expansion of parasitic weeds in the fields of developing countries is threatening the food supply and calls for simple procedures to combat these weeds. Strigolactone analogues represent a promising approach for such control through suicidal germination, i.e., parasitic seed germination without the presence of the host causing parasite death. In the present work, the synthesis of resorcinol-type strigolactone mimics related to debranones is reported. These compounds were highly stable even at alkaline pH levels and able to induce seed germination of parasitic plants Striga hermonthica and Phelipanche ramosa at low concentrations, EC50 ≈ 2 × 10-7 M ( Striga) and EC50 ≈ 2 × 10-9 M ( Phelipanche). On the other hand, the mimics had no significant effect on root architecture of Arabidopsis plants, suggesting a selective activity for parasitic seed germination, making them a primary target as suicidal germinators.

• MeSH
• klíčení účinky léků   MeSH
• laktony chemie   farmakologie   MeSH
• Orobanchaceae embryologie   fyziologie   MeSH
• regulátory růstu rostlin farmakologie   MeSH
• resorcinoly chemie   MeSH
• semena rostlinná účinky léků   fyziologie   MeSH
• Striga embryologie   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• laktony MeSH
• regulátory růstu rostlin MeSH
• resorcinol MeSH Prohlížeč
• resorcinoly MeSH

Strigolactones (SLs) constitute a new class of plant hormones of increasing importance in plant science. The structure of natural SLs is too complex for ready access by synthesis. Therefore, much attention is being given to design of SL analogues and mimics with a simpler structure but with retention of bioactivity. Here new hybrid type SL mimics have been designed derived from auxins, the common plant growth regulators. Auxins were simply coupled with the butenolide D-ring using bromo (or chloro) butenolide. D-rings having an extra methyl group at the vicinal C-3' carbon atom, or at the C-2' carbon atom, or at both have also been studied. The new hybrid type SL mimics were bioassayed for germination activity of seeds of the parasitic weeds S. hermonthica, O. minor and P. ramosa using the classical method of counting germinated seeds and a colorimetric method. For comparison SL mimics derived from phenyl acetic acid were also investigated. The bioassays revealed that mimics with a normal D-ring had appreciable to good activity, those with an extra methyl group at C-2' were also appreciably active, whereas those with a methyl group in the vicinal C-3' position were inactive (S. hermonthica) or only slightly active. The new hybrid type mimics may be attractive as potential suicidal germination agents in agronomic applications.

• Klíčová slova
• Auxins, O. minor, P. ramose, Parasitic weeds, S. hermonthica, SL mimics, Strigolactones, Suicidal germinations,
• MeSH
• biomimetické materiály chemická syntéza   chemie   farmakologie   MeSH
• klíčení účinky léků   MeSH
• kyseliny indoloctové chemická syntéza   chemie   farmakologie   MeSH
• laktony chemická syntéza   chemie   farmakologie   MeSH
• molekulární struktura MeSH
• plevel účinky léků   růst a vývoj   MeSH
• racionální návrh léčiv MeSH
• regulátory růstu rostlin chemická syntéza   chemie   farmakologie   MeSH
• stabilita léku MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kyseliny indoloctové MeSH
• laktony MeSH
• regulátory růstu rostlin MeSH