A carlactonoic acid methyltransferase that contributes to the inhibition of shoot branching in Arabidopsis

Abstract

Significance Strigolactones (SLs) are a group of apocarotenoid hormones, which regulates shoot branching and other diverse developmental processes in plants. The major bioactive form(s) of SLs as endogenous hormones has not yet been clarified. Here, we identify an Arabidopsis methyltransferase, CLAMT, responsible for the conversion of an inactive precursor to a biologically active SL that can interact with the SL receptor in vitro. Reverse genetic analysis showed that this enzyme plays an essential role in inhibiting shoot branching. This mutant also contributed to specifying the SL-related metabolites that could move from root to shoot in grafting experiments. Our work has identified a key enzyme necessary for the production of the bioactive form(s) of SLs.

Environmental strigolactone drives early growth responses to neighboring plants and soil volume in pea

“…Our recent work in wheat shows that plants emit and detect the concentration of a “substrate volume-sensing signal” (SVS), which allows them to detect their available soil volume and proactively modulate their shoot growth to match the long-term availability of soil resources. 29 Like SLs in this study, an SVS primarily affects shoot growth, and its effects are first visible between 3 and 4 weeks post-gemination. 31 As such we believe that SLs are SVSs.…”

“…28 However, recent research suggests an emerging picture in which the canonical SLs do not act as hormonal signals within plants; this is the role of non-canonical SLs, which in turn do not act as exuded signals. 29,30 Thus, although there is a reduction in the higher-abundance canonical SLs in crowded plants, this does not necessarily imply a reduction in the lower-abundance non-canonical SLs. In this context, it is notable that expression of CYP711A10 is not decreased in crowded plants, unlike all other SL biosynthesis genes (Figure 4F).…”

Maize resistance to witchweed through changes in strigolactone biosynthesis

“…1A). The maize gene is an ortholog of At4g36470 , which was recently found to encode a carlactonoic acid methyltransferase CLAMT in Arabidopsis ( 40 , 41 ).…”

Strigolactones as a hormonal hub for the acclimation and priming to environmental stress in plants

“…After carlactone exits the plastid, the pathway diversifies and more than one biosynthetic options are available in different species. In arabidopsis, the CYP711A MAX1 (Abe et al, 2014 ; Seto et al, 2014 ), CARLACTONOIC ACID METHYLTRANSFERASE (CLAMT) (Mashiguchi et al, 2022 ; Wakabayashi et al, 2021 ) and LATERAL BRANCHING OXIDASE (LBO) (Brewer et al, 2016 ) cooperate to produce respectively the non‐canonical strigolactones carlactonoic acid, methyl carlactonoate and hydroxymethyl carlactonoate, even though there is still uncertainty on the fine details of LBO activity (Mashiguchi et al, 2022 ) (Figure 1 left).…”