Phytochromes mediate germination inhibition under red, far-red, and white light in Aethionema arabicum

0575857 - ÚEB 2024 RIV US eng J - Journal Article
Mérai, Z. - Xu, F. - Musilek, A. - Ackerl, F. - Khalil, S. - Soto-Jiménez, L. M. - Lalatović, K. - Klose, C. - Tarkowská, Danuše - Turečková, Veronika - Strnad, Miroslav - Scheid, O. M.
Phytochromes mediate germination inhibition under red, far-red, and white light in Aethionema arabicum.
Plant Physiology. Roč. 192, č. 2 (2023), s. 1584-1602. ISSN 0032-0889. E-ISSN 1532-2548
R&D Projects: GA MŠMT(CZ) EF16_019/0000738; GA ČR(CZ) GA21-07661S
Institutional support: RVO:61389030
Keywords : SEED-GERMINATION * BLUE-LIGHT * ARABIDOPSIS-THALIANA
OECD category: Biochemistry and molecular biology
Impact factor: 7.4, year: 2022
Method of publishing: Open access
https://doi.org/10.1093/plphys/kiad138

The view on the role of light during seed germination stems mainly from studies with Arabidopsis (Arabidopsis thaliana), where light is required to initiate this process. In contrast, white light is a strong inhibitor of germination in other plants, exemplified by accessions of Aethionema arabicum, another member of Brassicaceae. Their seeds respond to light with gene expression changes of key regulators converse to that of Arabidopsis, resulting in opposite hormone regulation and prevention of germination. However, the photoreceptors involved in this process in A. arabicum remain unknown. Here, we screened a mutant collection of A. arabicum and identified koy-1, a mutant that lost light inhibition of germination due to a deletion in the promoter of HEME OXYGENASE 1, the gene for a key enzyme in the biosynthesis of the phytochrome chromophore. koy-1 seeds were unresponsive to red- and far-red light and hyposensitive under white light. Comparison of hormone and gene expression between wild type and koy-1 revealed that very low light fluence stimulates germination, while high irradiance of red and far-red light is inhibitory, indicating a dual role of phytochromes in light-regulated seed germination. The mutation also affects the ratio between the 2 fruit morphs of A. arabicum, suggesting that light reception via phytochromes can fine-tune several parameters of propagation in adaptation to conditions in the habitat.
Permanent Link: https://hdl.handle.net/11104/0345562