Strigolactones (SLs),a group of small carotenoid-derived terpenoid lactones,have been recently identified as plant hormones controlling plant architecture through modulating shoot and root branching (Brewer et al.,2013).SLs were first discovered in the rhizosphere because of their involvement in both symbiotic and parasitic interactions.Deficiencies in SL biosynthesis and perception lead to excessive growth of axillary bud,which is exemplified through various mutants such as max1,max2,max3,and max4 (more axillary growth) in Arabidopsis,d27,d10,d14,d3 (dwarf) in rice,dad3,dad1,dad2 (decreased apical dominance) in petunia,and rms5,rms1,rms4 (ramosus) in pea (de Saint Germain et al.,2013).Among these,D14/AtD14/DAD2 and D3/MAX2/PhMAX2A,which encode a predicted α/β-fold hydrolase and an F-box protein,respectively,have been proved to play important roles in SLs perception (Hamiaux et al.,2012;Zhao et al.,2013).A previous study shows that the D3 F-box protein is a key component of the Skp-Cullin-F-box (SCF) E3 ubiquitin ligase complex,implying that ubiquitination and proteasome-mediated degradation of targets,which were so far unknown,might be essential for SL signaling.