Strigolactones (SLs) are recently characterized phytohormones that play a multitude of roles during plant development and plant–microbial interactions. Initially discovered as germination stimulants of parasitic weeds (Cook et al., 1966), nowadays it is known that SLs regulate plant shoot and root architectures (reviewed in Al‐Babili & Bouwmeester, 2015), leaf senescence (Yamada et al., 2014), responses to biotic and abiotic stresses (Ha et al., 2014; Torres‐Vera et al., 2014), cytoskeletal dynamics, auxin transport (Shinohara et al., 2013; Pandya‐Kumar et al., 2014) and hyphal branching of arbuscular mycorrhizal fungi (AMF) (Akiyama et al., 2005). SLs are carotenoid derivatives synthesized via a pathway starting in plastids with the all‐trans‐β‐carotene/9‐cis‐β‐carotene isomerase D27 (reviewed in Lopez‐Obando et al., 2015). Two dioxygenases, CAROTENOID CLEAVAGE DIOXYGENASE 7 (CCD7)/MORE AXILLARY GROWTH 3 (MAX3)/DECREASED APICAL DOMINANCE 3 (DAD3) and CCD8/MAX4/DAD1, then synthesize the first bioactive SL precursor, carlactone. As a further step, plant‐specific members of cytochrome P450 mono‐oxygenases, MORE AXILLARY BRANCHES1 (MAX1) and MAX1 homologs produce canonical SLs such as orobanchol and ent‐2′‐epi‐5‐deoxystrigol (Zhang et al., 2014a), respectively most abundant in Petunia hybrida and Oryza sativa (Kretzschmar et al., 2012; Xie et al., 2013), or carlactonoic acid derivatives in Arabidopsis thaliana (Abe et al., 2014; Seto et al., 2014). SL synthesis takes place in several plant tissues: root tips, stem nodes, and along the root and shoot vasculature (Lopez‐Obando et al., 2015). Despite the ubiquitous biosynthesis, grafting experiments and tracking of SLs and of the SL‐mimicking molecule GR24 showed that SLs (or their precursors) move from the root to the shoot (Domagalska & Leyser, 2011; Sasse et al., 2015; Xie et al., 2015). However, wild‐type scions grafted on mutant root stocks do not show SL‐related phenotypes, supporting the hypothesis that shoots can produce enough SLs to regulate their architecture. PLEIOTROPIC DRUG RESISTANCE1 (PDR1) from P. hybrida is the main player for SL shootward transport and SL release to the soil. PDR1 is apically localized in the plasma membrane of cortex cells in root tips and outer‐laterally localized in hypodermal passage cells (HPCs), the entry point of mycorrhizal fungi (Sasse et al., 2015). The high activity of the PDR1 promoter (pPDR1) at the base of lateral axils and the bushy shoots of pdr1 ko mutants suggest that SL transport has an important role in inhibiting lateral bud outgrowth (Kretzschmar et al., 2012).