The switch from vegetative to reproductive growth — flowering — is a pivotal developmental transition that dictates plant fitness, crop yield and quality. Temperature is one of the most influential environmental cues that set flowering time. With accelerating climate change, deciphering how non-vernalizing temperatures (i.e., those not requiring prolonged cold) modulate flowering has become both a scientific priority and a breeding imperative.

 

Recently, Dr. Xiao Luo’s group Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agriculture Sciences in Weifang) published a comprehensive review, “Molecular Mechanisms of Temperature-Mediated Flowering Regulation: From Arabidopsis to Short-Day Crops”, in Plant, Cell & Environment. Starting with the model plant Arabidopsis and extending to major short-day crops — soybean, rice and maize—the review maps the complete molecular circuit from temperature perception to flowering activation, and outlines future research and breeding directions.

How do plants sense temperature? Multiple thermosensors cooperate
The review first distinguishes vernalization (weeks-to-months near-freezing) from non-vernalizing temperature responses. In Arabidopsis, several thermosensors have been characterized (Fig. 1): phyB: a dual light/thermo sensor that changes conformation and undergoes phase separation with temperature. CRY2: stability is temperature-dependent. UVR8: high temperature converts the active monomer to an inactive dimer. ELF3: undergoes temperature-dependent phase separation to directly perceive heat. These sensors translate temperature into biochemical signals that reprogram downstream gene expression.

 

Fig. 1. Thermosensors modulating flowering time in Arabidopsis.

 

High temperature accelerates Arabidopsis flowering through multi-layered circuits
At elevated temperature (Fig. 2): phyB shifts from active Pfr to inactive Pr, releasing PIF4, which directly activates FLOWERING LOCUS T (FT). Alternative splicing of FLOWERING LOCUS M (FLM) favors the FLM-δ isoform, reducing the SVP–FLM-β repressor complex. Histone dynamics: H2A.Z eviction from the FT promoter and increased H3K36me3 facilitate transcription and splicing, respectively. miR172 accumulates, repressing AP2-type repressors. Brassinosteroid signaling enhances BZR1 nuclear accumulation, cooperating with PIF4 to promote flowering.

 

Fig. 2. Mechanisms of high-temperature promotion of Arabidopsis flowering.

 

Low temperature delays Arabidopsis flowering via complex repression
Cold stress (Fig. 3): CBF transcription factors rapidly induce FLOWERING LOCUS C (FLC), repressing FT and SOC1. The ICE1–CBF–COR pathway integrates circadian cues (CCA1/LHY enhance CBF expression; COR27/28 bridge clock and cold signals). GI protein stability is reduced via COP1/HOS15-mediated degradation. DELLA proteins (when GA is limiting) block PIF3–FT interaction. Strikingly, FT protein itself is sequestered by phosphatidylglycerol (PG) in the cold, restricting its mobility.

 

Fig. 3. Mechanisms of low-temperature delay of Arabidopsis flowering.

 

From model to crops: conservation and divergence
The mechanism by which temperature regulates flowering time in crops exhibits both conservation and specificity (Fig. 4). In soybeans: Low temperature upregulates the expression of GmCOL2b, which enhances GmE1 expression to inhibit GmFT2a and GmFT5a; 35 °C enhances GmphyA-mediated GmE1 expression to delay flowering, whereas 30 °C activates GmCOL5a/5b to suppress GmE1 and promote flowering. In rice, low temperature suppresses OsEhd1 expression while activating OsGhd7, resulting in reduced expression of OsHd3a and OsRFT1. In maize, the expression of ZmHPC1 (a gene encoding phospholipase A1) is increased under low temperature. This leads to the production of more phospholipids that bind to ZmZCN8, ultimately inhibiting flowering.

 

Fig. 4. Temperature-mediated flowering pathways in key short-day crops.

 

Outlook: breeding for a warming world
Despite progress in Arabidopsis, crop-specific pathways remain underexplored. Future priorities include: dissecting crop-unique thermo-response circuits; studying flowering under dynamic temperature regimes; integrating AI and big-data approaches to predict flowering time across environments. These efforts will underpin the development of climate-resilient cultivars and safeguard global food security.

 

Prof. Xiao Luo (Shandong Key Laboratory of Precision Molecular Crop Design and Breeding, Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agriculture Sciences in Weifang) serves as both the corresponding author and first author of this article. Research Associates Xiulin Liu and Na Zheng from his laboratory are co-first authors, while Research Assistant Chengyang Song also participated in the paper writing. Prof. Yuehui He (Peking University Institute of Advanced Agricultural Sciences/National Key Laboratory of Wheat Improvement, Peking‐Tsinghua Center for Life Sciences, School of Advanced Agricultural Sciences) also contributed to writing and provided critical guidance. Peking University Institute of Advanced Agricultural Sciences is the first affiliation.

 

This study was supported by projects including the National Key R&D Program of China, Taishan Scholars Program, National High-Level Talents Special Support Plan, Natural Science Foundation of Shandong Province, National Natural Science Foundation of China.

 

Paper link: http://doi.org/10.1111/pce.15678