Methyl phenlactonoates are efficient strigolactone analogs with simple structure.

Boubacar A Kountche,Hidemitsu Nakamura,Imran Haider,Kai Jiang,Kei Hirabayashi,Kun-Peng Jia,Masaru Tanokura,Muhammad Jamil,Salim Al-Babili,Shawkat Ali,Stefan T Arold,Tadao Asami,Umar S Hameed,Valentine O Ntui,Xiujie Guo,Ying Lyu

doi:10.1093/jxb/erx438

Abstract

Strigolactones (SLs) are a new class of phytohormones that also act as germination stimulants for root parasitic plants, such as Striga spp., and as branching factors for symbiotic arbuscular mycorrhizal fungi. Sources for natural SLs are very limited. Hence, efficient and simple SL analogs are needed for elucidating SL-related biological processes as well as for agricultural applications. Based on the structure of the non-canonical SL methyl carlactonoate, we developed a new, easy to synthesize series of analogs, termed methyl phenlactonoates (MPs), evaluated their efficacy in exerting different SL functions, and determined their affinity for SL receptors from rice and Striga hermonthica. Most of the MPs showed considerable activity in regulating plant architecture, triggering leaf senescence, and inducing parasitic seed germination. Moreover, some MPs outperformed GR24, a widely used SL analog with a complex structure, in exerting particular SL functions, such as modulating Arabidopsis roots architecture and inhibiting rice tillering. Thus, MPs will help in elucidating the functions of SLs and are promising candidates for agricultural applications. Moreover, MPs demonstrate that slight structural modifications clearly impact the efficiency in exerting particular SL functions, indicating that structural diversity of natural SLs may mirror a functional specificity.

Highlights

Strigolactones (SLs) are secondary metabolites originally (Xie et al, 2010)
SLs were shown to induce identified as root-derived chemical signals inducing seed ger- hyphal branching in arbuscular mycorrhizal (AM) fungi, mination in root parasitic plants of the family Orobanchaceae which is required for establishing beneficial AM symbiosis
We developed a new series of SLs analogs, methyl phenlactonoates (MPs), which can be synthesized and which resemble the non-canonical SL methyl carlactonoate

Summary

Introduction

Strigolactones (SLs) are secondary metabolites originally (Xie et al, 2010). Later, SLs were shown to induce identified as root-derived chemical signals inducing seed ger- hyphal branching in arbuscular mycorrhizal (AM) fungi, mination in root parasitic plants of the family Orobanchaceae which is required for establishing beneficial AM symbiosis2320 | Jamil et al.(Akiyama et al, 2005). Canonical SLs, such as strigol and orobanchol, contain a tricyclic lactone (ABC-ring) as a second moiety and are divided, depending on stereochemistry of the B/C-junction, into strigol-like (β-orientation, up) and orobanchol-like (α-orientation, down) SLs (Ueno et al, 2011; Xie et al, 2013). Besides the stereochemistry of the B/C-junction, various modifications of the ABC-ring, such as hydroxylation at different positions, lead to the diversity of canonical SLs. Non-canonical SLs, such as methyl carlactonoate (Abe et al, 2014), heliolactone (Ueno et al, 2014) and zealactone (Charnikhova et al, 2017; Xie et al, 2017), do not have an ABC-lactone as a second moiety. The question of whether and how structural diversity leads to functional specificity of the around 25 known natural SLs is largely elusive (Xie, 2016)

Methods

Results

Conclusion