Light on perenniality: Para-dormancy is based on ABA-GA antagonism and endo-dormancy on the shutdown of GA biosynthesis

0578551 - ÚEB 2024 RIV US eng J - Journal Article
Veerabagu, M. - van der Schoot, C. - Turečková, Veronika - Tarkowská, Danuše - Strnad, Miroslav - Rinne, P. L.H.
Light on perenniality: Para-dormancy is based on ABA-GA antagonism and endo-dormancy on the shutdown of GA biosynthesis.
Plant Cell and Environment. Roč. 46, č. 6 (2023), s. 1785-1804. ISSN 0140-7791. E-ISSN 1365-3040
R&D Projects: GA MŠMT(CZ) EF16_019/0000738
Institutional support: RVO:61389030
Keywords : 1,3-β-glucanase * abscisic acid * branching * callose * gibberellins * plasmodesmata * prolepsis * syllepsis
OECD category: Biochemical research methods
Impact factor: 7.3, year: 2022
Method of publishing: Open access
https://doi.org/10.1111/pce.14562

Perennial para- and endo-dormancy are seasonally separate phenomena. Whereas para-dormancy is the suppression of axillary buds (AXBs) by a growing shoot, endo-dormancy is the short-day elicited arrest of terminal and AXBs. In hybrid aspen (Populus tremula x P. tremuloides) compromising the apex releases para-dormancy, whereas endo-dormancy requires chilling. ABA and GA are implicated in both phenomena. To untangle their roles, we blocked ABA biosynthesis with fluridone (FD), which significantly reduced ABA levels, downregulated GA-deactivation genes, upregulated the major GA3ox-biosynthetic genes, and initiated branching. Comprehensive GA-metabolite analyses suggested that FD treatment shifted GA production to the non-13-hydroxylation pathway, enhancing GA4 function. Applied ABA counteracted FD effects on GA metabolism and downregulated several GA3/4-inducible α- and γ-clade 1,3-β-glucanases that hydrolyze callose at plasmodesmata (PD), thereby enhancing PD-callose accumulation. Remarkably, ABA-deficient plants repressed GA4 biosynthesis and established endo-dormancy like controls but showed increased stress sensitivity. Repression of GA4 biosynthesis involved short-day induced DNA methylation events within the GA3ox2 promoter. In conclusion, the results cast new light on the roles of ABA and GA in dormancy cycling. In para-dormancy, PD-callose turnover is antagonized by ABA, whereas in short-day conditions, lack of GA4 biosynthesis promotes callose deposition that is structurally persistent throughout endo-dormancy.
Permanent Link: https://hdl.handle.net/11104/0347549