Takaya Kisugi's research while affiliated with Tohoku University and other places

... The over-branching phenotype of the SL-deficient mutant sb1 mostly disappeared when it was grafted onto a wild-type rootstock ( Figure 5A, Table S1), supporting the notion that the roots are the primary site of SL biosynthesis, which are transported acropetally to the shoots through the xylem [28,47,59]. Similar results were previously reported in other plant species [28,[59][60][61][62][63]. Over-branching, accompanied by loss of fruit yield, was also recovered in a wild-type (M82) scion grafted onto the SL-deficient rootstock of sb1 ( Figure 5 and Table S1). ...

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Tomato Mutants Reveal Root and Shoot Strigolactone Involvement in Branching and Broomrape Resistance

... Outside flowering plants, SL synthesis has been characterized in the moss Physcomitrella patens, where CCD7 and CCD8 act consecutively in CL synthesis as in angiosperms (Proust et al, 2011;Decker et al, 2017). There is some uncertainty about which strigolactones are ultimately synthesised by P. patens, with recent analysis suggesting only CL is produced, consistent with the lack of MAX1 orthologue in this species (Decker et al, 2017;Yoneyama et al, 2017). In general, conclusions regarding SL synthesis outside the angiosperms are based on very limited sampling of sequences. ...

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Reassessing the evolution of strigolactone synthesis and signalling

... SLs are a group of terpenoid phytohormones responsible for a wide range of developmental processes, especially the branching of shoots, and responses to stresses (Korek and Marzec 2023). SLs are sensed by their receptor DWARF14 (AtD14/OsD14) in Arabidopsis and rice, respectively (Seto et al. 2019). The activated receptor, in turn, interacts with an F-box protein MORE AXILLARY GROWTH 2 (MAX2) in Arabidopsis, an ortholog of DWARF3 (D3) in rice, from the SCF complex SCF MAX2 , and SL repressors SUPPRESSORS OF MAX2 1-LIKE 6/7/8 (SMXL6/7/8) in Arabidopsis or D53 in rice, reducing the stability of SMXL6/7/8 (D53) proteins (Jiang et al. 2013, Zhou et al. 2013a). ...

Reference:

pcae047-1

... Another intriguing question in the biology of SLs is related to their structural diversity ( Table 1 provides a summary of identified SLs in different species) [12,19,24,29,31,36,[41][42][43][44][45][46]51,52,65,66,73,74,[79][80][81][82][83][84][85][86][87][88][89][90][91][92] and the structure-biological function relationship: do all SLs fulfill the same hormonal functions in planta and act as rhizospheric signals [93][94][95][96]? Both SL classes are assumed to height, stem thickness, and leaf senescence, whereas they inhibit shoot branching and the growth of adventitious and lateral roots [10,56] in the non-arbuscular mycorrhiza (AM) host arabidopsis. ...

Reference:

Distinguishing the functions of canonical strigolactones as rhizospheric signals

... Another intriguing question in the biology of SLs is related to their structural diversity ( Table 1 provides a summary of identified SLs in different species) [12,19,24,29,31,36,[41][42][43][44][45][46]51,52,65,66,73,74,[79][80][81][82][83][84][85][86][87][88][89][90][91][92] and the structure-biological function relationship: do all SLs fulfill the same hormonal functions in planta and act as rhizospheric signals [93][94][95][96]? Both SL classes are assumed to height, stem thickness, and leaf senescence, whereas they inhibit shoot branching and the growth of adventitious and lateral roots [10,56] in the non-arbuscular mycorrhiza (AM) host arabidopsis. ...

Reference:

Distinguishing the functions of canonical strigolactones as rhizospheric signals

... Moreover, the catalyzing property of CL and CLA of CYP711A subfamily to canonical SLs in seed plant was exclusively detected only in rice [71]. In a previous study on faba bean, a genitor of our R_Host was used as a resistant host, and orobanchol was not detected in its root exudates [72]. Whereas, orobanchol and orobanchol acetate were detected in the root exudates of the same S_Host variety used in our study [72]. ...

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Global changes in gene expression during compatible and incompatible interactions of faba bean (Vicia faba L.) during Orobanche foetida parasitism

... CK transports acropetally in xylem and synthesizes locally to promote shoot branching. SL, a new phytohormone, also transports acropetally from root to shoot but it inhibits shoot branching (Gomez-Roldan et al., 2008;Xie et al., 2016). It has also recently been proved that abscisic acid (ABA) and gibberellic acid (GA) are involved in shoot branching (Yao and Scott, 2015;Charnikhova et al., 2017). ...

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A Rapid Method for Quantifying RNA and Phytohormones From a Small Amount of Plant Tissue

... Hence, it has been proposed that SLs are longdistance signals translocated to shoots to exert their function in inhibiting shoot tillering/ branching. Grafting experiments [61,62] and liquid chromatography-mass spectrometry (LC-MS) quantification of SLs in shoot tissues, including xylem sap [51,[63][64][65][66], demonstrate that both classes of SLs can be transported upward from the root to the shoot. However, whether a specific SL molecule is the mobile inhibitor of shoot branching in plants remains unclear. ...

Reference:

Distinguishing the functions of canonical strigolactones as rhizospheric signals

... About 50 years ago, they were known to be seed germination stimulants in root parasitic plants, e.g., Striga, Orobanche, and Phelipanche (Ruyter-Spira et al. 2013). A single plant species can produce various types of SLs, whereas in case of intraspecific varieties, blends of different kinds and amounts of SL molecules can be observed (Yoneyama et al. 2013). Though SLs are synthesized and accumulated in small quantities in roots, other parts of the plants can also produce these biomolecules. ...

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Targeting Plant Hormones to Develop Abiotic Stress Resistance in Wheat

... Orobanchol, a major naturally occurring SL, has been detected in the root exudate of numerous plants, including monocots like rice (Oryza sativa) (Zhang et al., 2014) and dicots such as Sonalaceae , Fabaceae (Ueno et al., 2011), Cucurbitaceae (Khetkam et al., 2014), and Linaceae (Xie et al., 2009a). Regarding SL biosynthesis, enzyme reactions catalyzed by DWARF27 (D27), carotenoid cleavage dioxygenase 7 (CCD7), and CCD8 are known to convert all-trans-b-carotene to carlactone (Alder et al., 2012). ...

Reference:

2-oxoglutarate-dependent dioxygenases and BAHD acyltransferases drive the structural diversification of orobanchol in Fabaceae plants