Strigolactones (SL) are plant hormones that repress shoot branching. They are also known for their activity in the rhizosphere, in particular to stimulate symbiosis with endomycorrhizal fungi. More than thirty natural SLs with diverse structures have been characterised and plants can synthesize a cocktail of many SLs, sometimes specific to plant families or species. They can be classified into two groups according to their structures, the canonical SLs, with an "ABC" tricycle linked to the butenolide "D" and the non-canonical SLs without the "ABC" tricycle. The biosynthetic pathways of SLs begins with the successive conversion of trans-ß-carotenes via three enzymes. These steps, apparently common to all vascular plants, constitute what is known as the "CORE PATHWAY". The rest of the biosynthetic pathway, on the other hand, diversify and seems to vary greatly between species. Studies have highlighted the central role of the MAX1 protein (CYP711A) in the SL biosynthetic pathway. Its role is well described in Arabidopsis, tomato and rice, but the functions in other species are poorly described. There are two homologs in legumes, only one in other Dicotyledons whose genome has been sequenced, and at least five in Monocotyledons such as rice. Studying the MAX1 proteins in different species is important to understand the diversity of SLs. My project focuses on the two MAX1 homologs in Pea. We have obtained several mutants named Psmax1s by TILLING approaches. We are performing in vitro enzymatic tests and in planta SL quantifications to investigate the biochemical and biological functions of the pea MAX1. Unexpectedly, single and double mutants do not show the high branching phenotype characteristic of SLs mutants. However, these Psmax1s are deficient in the known canonical SLs present in Pea. Our results suggest that the branching inhibitory signal is not one of the strigolactones described so far in pea and that the real branching inhibitor signal remains to be discovered.