Record ID No. |
5235 |
Author(s) |
Mori N., Nishiuma K., Sugiyama T., Hayashi H., Akiyama K. , 2016 |
Affiliation |
Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan. Email: sv201042@edu.osakafu-u.ac.jp |
Title |
Carlactone-type strigolactones and their synthetic analogues as inducers of hyphal branching in arbuscular mycorrhizal fungi |
Source. Vol.(no):Page |
Phytochemistry. 130:90-98p. |
Categories |
Arbuscular Mycorrhiza |
Subjects |
Biological Interaction |
Sub-subjects |
Fungal evaluation |
Host |
Plants |
Organism |
Gigaspora Margarita |
Country |
Japan |
Abstracts |
Hyphal branching in the vicinity of host roots is a host recognition response of arbuscular mycorrhizal fungi. This morphological event is elicited by strigolactones. Strigolactones are carotenoid-derived terpenoids that are synthesized from carlactone and its oxidized derivatives. To test the possibility that carlactone and its oxidized derivatives might act as host-derived precolonization signals in arbuscular mycorrhizal symbiosis, carlactone, carlactonoic acid, and methyl carlactonoate as well as monohydroxycarlactones, 4-, 18-, and 19-hydroxycarlactones, were synthesized chemically and evaluated for hyphal branching-inducing activity in germinating spores of the arbuscular mycorrhizal fungus Gigaspora margarita. Hyphal branching activity was found to correlate with the degree of oxidation at C-19 methyl. Carlactone was only weakly active (100 ng/disc), whereas carlactonoic acid showed comparable activity to the natural canonical strigolactones such as strigol and sorgomol (100 pg/disc). Hydroxylation at either C-4 or C-18 did not significantly affect the activity. A series of carlactone analogues, named AD ester and AA’D diester, was synthesized by reacting formyl Meldrum’s acid with benzyl, cyclohexylmethyl, and cyclogeranyl alcohols (the A-ring part), followed by coupling of the potassium enolates of the resulting formylacetic esters with the D-ring butenolide. AD ester analogues exhibited moderate activity (1 ng–100 pg/disc), while AA’D diester analogues having cyclohexylmethyl and cyclogeranyl groups were highly active on the AM fungus (10 pg/disc). These results indicate that the oxidation of methyl to carboxyl at C-19 in carlactone is a prerequisite but BC-ring formation is not essential to show hyphal branching activity comparable to that of canonical strigolactones. |