条纹色调(SL),一类类胡萝卜素来源的激素,通过调节与共生丛枝菌根真菌(AM)的地下通讯并控制芽和根结构,在开花植物中发挥关键作用。虽然核心SL基因的功能已在许多植物中得到表征,它们在苔藓等非气管植物中的作用需要进一步研究。在这项研究中,我们采用了鼠李草模型,缺乏可检测的SL产生和关键SL生物合成基因的直系同源物,包括类胡萝卜素裂解酶8(CCD8)和更多的轴生长1(MAX1)。然而,它保留了一些SL通路组件,包括DWARF27(D27)和CCD7。为了帮助阐明多态分枝杆菌中这些剩余成分的功能,产生MpD27-1、MpD27-2和MpCCD7的敲除突变体。这些突变体与野生型对照的表型比较揭示了这些基因在调节gemmae从gemma杯中的释放以及gemmae在黑暗中的发芽和生长方面的新作用。Mpd27-1,Mpd27-2和Mpccd7突变体显示参与光合作用的基因的转录物丰度较低,如早期光感(ELI),和应激反应,如晚期胚胎发生丰富(LEA),但表现出更高的乙烯反应因子(ERF)和SL和类胡萝卜素相关基因的转录水平,如萜烯合成酶(TS),CCD7和软骨-视网膜酰基转移酶(LRAT)。此外,SL途径中的多形性分枝杆菌突变体显示出增加的类胡萝卜素含量。这揭示了MpD27-1,MpD27-2和MpCCD7在控制释放方面的作用,发芽,和Gemmae在不同光照条件下的生长。这些发现增强了我们对非开花植物中SL生物合成基因的调节功能的理解。
Strigolactones (SLs), a class of carotenoid-derived hormones, play a crucial role in flowering plants by regulating underground communication with symbiotic arbuscular mycorrhizal fungi (AM) and controlling shoot and root architecture. While the functions of core SL genes have been characterized in many plants, their roles in non-tracheophyte plants like liverworts require further investigation. In this study, we employed the model liverwort species Marchantia polymorpha, which lacks detectable SL production and orthologs of key SL biosynthetic genes, including CAROTENOID CLEAVAGE DIOXYGENASE 8 (CCD8) and MORE AXILLARY GROWTH 1 (MAX1). However, it retains some SL pathway components, including DWARF27 (D27) and CCD7. To help elucidate the function of these remaining components in M. polymorpha, knockout mutants were generated for MpD27-1, MpD27-2 and MpCCD7. Phenotypic comparisons of these mutants with the wild-type control revealed a novel role for these genes in regulating the release of gemmae from the gemma cup and the germination and growth of gemmae in the dark. Mpd27-1, Mpd27-2, and Mpccd7 mutants showed lower transcript abundance of genes involved in photosynthesis, such as EARLY LIGHT INDUCED (ELI), and stress responses such as LATE EMBRYOGENESIS ABUNDANT (LEA) but exhibited higher transcript levels of ETHYLENE RESPONSE FACTORS (ERFs) and SL and carotenoid related genes, such as TERPENE SYNTHASE (TS), CCD7 and LECITHIN-RETINAL ACYL TRANSFERASE (LRAT). Furthermore, the mutants of M. polymorpha in the SL pathway exhibited increased contents of carotenoid. This unveils a previously unrecognized role for MpD27-1, MpD27-2 and MpCCD7 in controlling release, germination, and growth of gemmae in response to varying light conditions. These discoveries enhance our comprehension of the regulatory functions of SL biosynthesis genes in non-flowering plants.