SMAX1 interacts with DELLA protein to inhibit seed germination under weak light conditions via gibberellin biosynthesis in Arabidopsis

Peipei Xu; Jinbo Hu; Haiying Chen; Weiming Cai

doi:10.1016/j.celrep.2023.112740

SMAX1 interacts with DELLA protein to inhibit seed germination under weak light conditions via gibberellin biosynthesis in Arabidopsis

Cell Rep. 2023 Jul 25;42(7):112740. doi: 10.1016/j.celrep.2023.112740. Epub 2023 Jul 4.

Authors

Peipei Xu¹, Jinbo Hu², Haiying Chen³, Weiming Cai⁴

Affiliations

¹ Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai 200032, China; University of Chinese Academy of Sciences, Beijing 100039, China. Electronic address: ppxu@cemps.ac.cn.
² Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai 200032, China; University of Chinese Academy of Sciences, Beijing 100039, China.
³ Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai 200032, China.
⁴ Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, No. 300 Fenglin Road, Shanghai 200032, China. Electronic address: wmcai@cemps.ac.cn.

PMID: 37405917
DOI: 10.1016/j.celrep.2023.112740

Abstract

Karrikins (KARs) were first identified as a class of small-molecule chemicals derived from smoke that promote seed germination. However, the implied mechanism is still not well understood. Here, we find that KAR signaling mutants have a lower germination percentage than that of wild type under weak light conditions, and KARs promote seed germination through transcriptional activation of gibberellin (GA) biosynthesis via SMAX1. SMAX1 interacts with the DELLA proteins REPRESSOR of ga1-3-LIKE 1 (RGL1) and RGL3. The interaction enhances the transcriptional activity of SMAX1 and inhibits GIBBERELLIN 3-oxidase 2 (GA3ox2) gene expression. The KAR signaling mutant seed germination defect under weak light is partially rescued by exogenous application of GA₃ or by GA3ox2 overexpression, and the rgl1 rgl3 smax1 triple mutant exhibits higher germination rates under weak light than the smax1 mutant. Thus, we show a crosstalk between KAR and GA signaling pathways via a SMAX1-DELLA module in regulating seed germination in Arabidopsis.

Keywords: CP: Plants; DELLA; auto-regulated transcription factor; germination; gibberellin; karrikin.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Arabidopsis Proteins* / genetics
Arabidopsis Proteins* / metabolism
Arabidopsis* / metabolism
Gene Expression Regulation, Plant
Germination / genetics
Gibberellins* / metabolism
Intracellular Signaling Peptides and Proteins* / metabolism
Seeds / genetics

Substances

Arabidopsis Proteins
Gibberellins
Intracellular Signaling Peptides and Proteins
SMAX1 protein, Arabidopsis
GAI protein, Arabidopsis