Triflumizole as a Novel Lead Compound for Strigolactone Biosynthesis Inhibitor

Kojiro Kawada,Tadao Asami,Ikuo Takahashi,Yuya Uchida,Takahito Nomura,Yasuyuki Sasaki,Shunsuke Yajima,Shinsaku Ito

doi:10.3390/molecules25235525

Abstract

Strigolactones (SLs) are carotenoid-derived plant hormones involved in the development of various plants. SLs also stimulate seed germination of the root parasitic plants, Striga spp. and Orobanche spp., which reduce crop yield. Therefore, regulating SL biosynthesis may lessen the damage of root parasitic plants. Biosynthetic inhibitors effectively control biological processes by targeted regulation of biologically active compounds. In addition, biosynthetic inhibitors regulate endogenous levels in developmental stage- and tissue-specific manners. To date, although some chemicals have been found as SL biosynthesis inhibitor, these are derived from only three lead chemicals. In this study, to find a novel lead chemical for SL biosynthesis inhibitor, 27 nitrogen-containing heterocyclic derivatives were screened for inhibition of SL biosynthesis. Triflumizole most effectively reduced the levels of rice SL, 4-deoxyorobanchol (4DO), in root exudates. In addition, triflumizole inhibited endogenous 4DO biosynthesis in rice roots by inhibiting the enzymatic activity of Os900, a rice enzyme that converts the SL intermediate carlactone to 4DO. A Striga germination assay revealed that triflumizole-treated rice displayed a reduced level of germination stimulation for Striga. These results identify triflumizole as a novel lead compound for inhibition of SL biosynthesis.

Highlights

Strigolactones (SLs) are a group of terpenoid lactones derived from carotenoids
The results showed that triflumizole is a novel lead compound for SL biosynthesis inhibition in rice
To screen for compounds that inhibit SL biosynthesis in rice seedlings, the effects of 27 P450 inhibitors were evaluated, which are commercially available, as they are used as agrochemicals (Supplementary Material Figure S2)

Summary

Introduction

Strigolactones (SLs) are a group of terpenoid lactones derived from carotenoids. More than 20 SLs, including 4-deoxyorobanchol (4DO), orobanchol, and methyl carlactonoate (MeCLA), have been reported from various plant species [1]. SLs function as plant hormones that regulate several important developmental processes in plants, including the regulation of shoot branching and stress tolerance [2,3,4]. SLs are allelochemicals that induce branching of hyphae in arbuscular mycorrhizal fungi and germination in root parasitic plants [5,6]. Root parasitic plants, such as Orobanche spp. and Striga spp., are harmful for crop production in. Sub-Saharan Africa, the Middle East, and Asia [7]. In the savanna regions of Africa alone, annual losses amount to $US 7 billion [8]. It is possible that inhibition of SL biosynthesis could reduce these damages [3]

Methods

Results

Conclusion