Structure-activity relationship studies of strigolactone-related molecules for branching inhibition in garden pea: molecule design for shoot branching.
Initially known for their role in the rhizosphere in stimulating the seed germination of parasitic weeds such as the Striga and Orobanche species, and later as host recognition signals for arbuscular mycorrhizal fungi, strigolactones (SLs) were recently rediscovered as a new class of plant hormones involved in the control of shoot branching in plants. Herein, we report the synthesis of new SL analogs and, to our knowledge, the first study of SL structure-activity relationships for their hormonal activity in garden pea (Pisum sativum). Comparisons with their action for the germination of broomrape (Phelipanche ramosa) are also presented. The pea rms1 SL-deficient mutant was used in a SL bioassay based on axillary bud length after direct SL application on the bud. This assay was compared with an assay where SLs were fed via the roots using hydroponics and with a molecular assay in which transcript levels of BRANCHED1, the pea homolog of the maize TEOSINTE BRANCHED1 gene were quantified in axillary buds only 6 h after application of SLs. We have demonstrated that the presence of a Michael acceptor and a methylbutenolide or dimethylbutenolide motif in the same molecule is essential. It was established that the more active analog 23 with a dimethylbutenolide as the D-ring could be used to control the plant architecture without strongly favoring the germination of P. ramosa seeds. Bold numerals refer to numbers of compounds.
Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles, Unité Propre de Recherche 2301 Centre National de la Recherche Scientifique, F-91198 Gif-sur-Yvette cedex, France. boyer@icsn.cnrs-gif.fr
François-Didier
FD
Boyer
Alexandre
A
de Saint Germain
Jean-Paul
JP
Pillot
Jean-Bernard
JB
Pouvreau
Victor Xiao
VX
Chen
Suzanne
S
Ramos
Arnaud
A
Stévenin
Philippe
P
Simier
Philippe
P
Delavault
Jean-Marie
JM
Beau
Catherine
C
Rameau
D001681:Biological Assay; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018527:Hydroponics; D007783:Lactones / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D008954:Models, Biological; D009024:Morphogenesis / Q000187:drug effects*; D010084:Oxidation-Reduction / Q000187:drug effects; D018532:Pisum sativum / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
D007783:Lactones; D010940:Plant Proteins; D012333:RNA, Messenger