Physcomitrella patens MAX2 characterization suggests an ancient role for this F‐box protein in photomorphogenesis rather than strigolactone signalling. Issue 2 (21st May 2018)

• Record Type: Journal Article
• Authors: Lopez‐Obando, Mauricio; de Villiers, Ruan; Hoffmann, Beate; Ma, Linnan; de Saint Germain, Alexandre; Kossmann, Jens; Coudert, Yoan; Harrison, C. Jill; Rameau, Catherine; Hills, Paul; Bonhomme, Sandrine
• Is Part Of: New phytologist. Volume 219:Issue 2(2018)
• Page Start: 743
• Page End: 756
• Publication Date: 2018-05-21
• Subjects: bryophyte -- F‐box protein -- hormone signalling -- moss -- photomorphogenesis -- strigolactone; Botany -- Periodicals; 580
• DOI: 10.1111/nph.15214
• Languages: English
• ISSNs: 0028-646X

Abstract

Summary: Strigolactones (SLs) are key hormonal regulators of flowering plant development and are widely distributed amongst streptophytes. In Arabidopsis, SLs signal via the F‐box protein MORE AXILLARY GROWTH2 (MAX2), affecting multiple aspects of development including shoot branching, root architecture and drought tolerance. Previous characterization of a Physcomitrella patens moss mutant with defective SL synthesis supports an ancient role for SLs in land plants, but the origin and evolution of signalling pathway components are unknown. Here we investigate the function of a moss homologue of MAX2, PpMAX2, and characterize its role in SL signalling pathway evolution by genetic analysis. We report that the moss Ppmax2 mutant shows very distinct phenotypes from the moss SL‐deficient mutant. In addition, the Ppmax2 mutant remains sensitive to SLs, showing a clear transcriptional SL response in dark conditions, and the response to red light is also altered. These data suggest divergent evolutionary trajectories for SL signalling pathway evolution in mosses and vascular plants. In P. patens, the primary roles for MAX2 are in photomorphogenesis and moss early development rather than in SL response, which may require other, as yet unidentified, factors.