Eview and editing, A.B., A.J.K. as well as a.P.Eview and editing, A.B., A.J.K. in addition

Eview and editing, A.B., A.J.K. as well as a.P.
Eview and editing, A.B., A.J.K. in addition to a.P.-K.; visualization, A.B.; supervision, A.P.-K. All authors have study and agreed towards the published version in the manuscript. Funding: This study was funded by internal financing of the Healthcare 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 critical roles in plant growth and development (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 based on the stereochemistry with the C-ring (Al-Babili and Bouwmeester, 2015; Figure 1). Distinctive SL structures have been reported to exhibit distinct parasitic weed germination activities (Yoneyama et al., 2010; Zwanenburg and Pospisil, 2013). By way of example, SLs exhibiting higher germination stimulation activity toward S. gesnerioides induced low germination in S. hermonthica, though a number of SLs of high germination stimulation activity to S. hermonthica inhibit the germination of S. gesnerioides (Nomura et al., 2013). Recently, LOW GERMINATION STIMULANT 1 (LGS1) has been identified to be accountable for the Striga germination stimulant activity in sorghum and missing in the Striga-resistant sorghum varieties (Gobena et al., 2017), which make distinct SL profiles, i.e., (S)-type 5-deoxystrigol (5DS) and (O)-type OB, respectively (Gobena et al., 2017). LGS1 is actually a putative sulfotransferase (SOT), which normally catalyzes the transfer of a sulfonate group from 3 -phosphoadenosine five -phosphosulfate (PAPS) to a hydroxyl group of acceptor molecules (Paul et al., 2012). The mechanism of how LGS1 regulates SL profiles between 5DS and OB in sorghum remains unclear. Strigolactones are DNA Methyltransferase Species synthesized from carlactone (CL), which is then converted to diverse SL structures by different downstream tailoring enzymes specifically cytochrome P450s (CYPs) (Figure 1; Wang and Bouwmeester, 2018; Chesterfield et al., 2020). The two major groups of CYP thatFrontiers in Plant Science | www.frontiersinDecember 2021 | PI3KC2β Purity & Documentation Volume 12 | ArticleWu and LiIdentification of Sorghum LGScontribute towards the structural diversity downstream of CL belong to CYP711A and CYP722C subfamily (Nelson et al., 2008). The most beneficial studied CYP711A is Extra AXILLARY GROWTH1 (MAX1) from Arabidopsis thaliana (AtMAX1), which converts CL to carlactonoic acid (CLA) and is functionally conserved in dicots (Challis et al., 2013). However, monocots, specifically the economically important Poaceae family members, generally encode much more than one particular 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). For example, rice has 5 MAX1 homologs, with CYP711A2 catalyzing the conversion of CL to 4-deoxyorobanchol (4DO) and CYP711A3 further oxidizing 4DO to OB (Zhang et al., 2014). Most CYP711As encoded by monocot plants remain to be characterized. The other key group of SL-synthesizing CYPs, CYP722C subfamily, catalyzes the conversion of CLA towa.