Eview and editing, A.B., A.J.K. and a.P.Eview and editing, A.B., A.J.K. as well as a.P.-K.;

Eview and editing, A.B., A.J.K. and a.P.
Eview and editing, A.B., A.J.K. as well as a.P.-K.; visualization, A.B.; supervision, A.P.-K. All authors have read and agreed to the published version of the manuscript. Funding: This study was funded by internal financing on the Medical University of Bialystok (SUB/1/DN/21/006/1150). Information Availability Statement: Not applicable. Conflicts of Interest: The authors declare no conflict of interest.
Strigolactones (SL) are a group of butanolide-containing molecules initially identified as seed germination stimulants for the parasitic weeds Striga and Orobanche (Cook et al., 1966; Samejima et al., 2016) and later characterized as phytohormones that play diverse essential roles in plant growth and improvement (Al-Babili and Bouwmeester, 2015; Zwanenburg and Blanco-Ania, 2018; Chesterfield et al., 2020). SLs may be divided into canonical and non-canonical SLs, with canonical SLs further grouped into strigol (S)- and orobanchol (OB) (O)-type SLs in accordance with the stereochemistry on the C-ring (Al-Babili and Bouwmeester, 2015; Figure 1). Various SL structures have been reported to exhibit distinct parasitic weed germination activities (Yoneyama et al., 2010; Zwanenburg and Pospisil, 2013). For example, SLs exhibiting high germination stimulation activity toward S. gesnerioides induced low germination in S. hermonthica, even though various SLs of higher germination stimulation activity to S. hermonthica inhibit the germination of S. gesnerioides (Nomura et al., 2013). Lately, LOW GERMINATION STIMULANT 1 (LGS1) has been identified to become responsible for the Striga germination stimulant activity in sorghum and missing in the Striga-resistant sorghum varieties (Gobena et al., 2017), which create distinct SL profiles, i.e., (S)-type 5-deoxystrigol (5DS) and (O)-type OB, respectively (Gobena et al., 2017). LGS1 can be a putative sulfotransferase (SOT), which usually catalyzes the transfer of a sulfonate group from 3 -phosphoadenosine 5 -phosphosulfate (PAPS) to a hydroxyl group of acceptor molecules (Paul et al., 2012). The mechanism of how LGS1 regulates SL profiles among 5DS and OB in sorghum remains unclear. Strigolactones are synthesized from carlactone (CL), that is then converted to diverse SL structures by many downstream tailoring enzymes specifically cytochrome P450s (CYPs) (Figure 1; Wang and Bouwmeester, 2018; Chesterfield et al., 2020). The two big groups of CYP thatFrontiers in Plant Science | www.frontiersinDecember 2021 | Volume 12 | ArticleWu and LiIdentification of Sorghum LGScontribute for the structural diversity downstream of CL belong to CYP711A and CYP722C subfamily (Nelson et al., 2008). The ideal studied CYP711A is More AXILLARY GROWTH1 (MAX1) from Arabidopsis thaliana (AtMAX1), which 15-PGDH MedChemExpress converts CL to carlactonoic acid (CLA) and is functionally conserved in dicots (Challis et al., 2013). However, monocots, particularly the economically important Poaceae household, normally encode a lot more than one CYP711As (Supplementary Table 1; Figure 2A; Supplementary Figure 1), with diverse functions distinct from AtMAX1 (Challis et al., 2013; Zhang et al., 2014; Marzec et al., 2020; Changenet et al., 2021). By way of example, rice has 5 MAX1 homologs, with CYP711A2 catalyzing the conversion of CL to 4-deoxyorobanchol (4DO) and CYP711A3 additional oxidizing 4DO to OB (Zhang et al., 2014). Most CYP711As encoded by c-Myc site monocot plants stay to be characterized. The other significant group of SL-synthesizing CYPs, CYP722C subfamily, catalyzes the conversion of CLA towa.