A newly published paper in Cell deciphered the mystery of how plants’ “heat-sensing decoders” achieve exquisite signal transmission from the membrane to the nucleus.

Plants do not have nervous systems. How do they sense changes in ambient temperature and initiate survival responses? In December 2025, the team of Hongxuan et al. published a study titled “A stepwise decoding mechanism for heat sensing in plants connections lipid remodeling to a nuclear signaling cascade” in the internationally authoritative academic journal Cell, which revealed a corner of this mystery. For the first time, a complete analysis of plant-perceived high-temperature signals was performed,  “ Three-step decoding mechanism”, perfectly connecting the physical changes of cell membranes with the regulation of gene expression in the nucleus.

1. Cell crisis under heat stress

Heat stress can rapidly destroy cell membrane structure and change the physical properties and composition of lipid bilayers. Among them, the rapid accumulation of Phosphatidic acid (PA).  is considered one of the early signs of heat stress.

However, a fundamental issue has long been unresolved: How do plants translate the physical signal of membrane lipid changes into biological signals that cells can understand?  How are these signals transmitted step by step to the cell nucleus and ultimately regulate gene expression?

2. Finding heat signals “first responders”

The research team started with two rice genotypes: Heat-sensitive HJX and Heat-resistant NIL-TT2HPS32. By integrating time-series transcriptome with lipid metabolome analysis, they screened candidate genes that responded rapidly to heat stress and whose expression patterns matched “sensor” characteristics.

DGK7 (diacylglycerol kinase 7) stood out from many candidates. Its expression is rapidly upregulated under heat stress and is closely related to TT2 (G protein γ subunit), a known negative regulator of heat tolerance.

Key experiment: Determining the cellular localization of DGK7

If DGK7 is indeed the “first responder” of the heat signal, it should be located at the site where the heat signal first occurs -the cell membrane. To this end, the research team conducted precise localization experiments using a specialized plant membrane protein isolation kit (Invent Biotechnologies, Cat# SM-005-P). Researchers efficiently isolated the cell membrane protein components of rice. Western Blot test results clearly show: DGK7-GFP fusion protein , specific enrichment in membrane protein fractions , while it is almost undetectable in the cytoplasmic fraction.

(I) Immunoblotting assay showing that DGK7-GFP exists in the PM protein fraction. GFP antibody was used to detect exogenous DGK7.

 

This seemingly simple yet crucial result spatially establishes DGK7 as Membrane-localized kinases The position sets the starting point for the entire heat signaling pathway. When conducting signaling studies, clarifying the subcellular localization of key proteins is essential.”

3. “Braking” mechanism of G protein

Interestingly, the researchers found that both the G protein gamma subunit TT2 and the beta subunit RGB1 interact with DGK7, and this interaction also occurs on the cell membrane.

Further research revealed that TT2 has a very clever mechanism of action: It inhibits the kinase activity of DGK7 by promoting dephosphorylation of serine at position 477 of DGK7.

The main function of DGK7 is the phosphorylation of diacylglycerols (DAGs) to phosphatidic acid (PA). Under normal conditions, the Ser477 site of DGK7 is phosphorylated and is in an activated state. When TT2 binds to it, DGK7 is dephosphorylated, and its activity is reduced, thereby reducing the production of PA.

This is equivalent to setting one upstream of the heat signaling pathway, “ Molecular brakes ”: When an overresponse is not required, the G protein system inhibits DGK7, preventing unnecessary energy expenditure and potential harm.

 

4. PA: From second messenger to “navigator”

PA has been extensively supported as a lipid second messenger, but this study reveals a new role for it: Regulators of enzyme activity and guides of nuclear localization.

The research team discovered a metal-dependent phosphodiesterase called MdPDE1, which is able to hydrolyze cyclic adenosine monophosphate (cAMP). Surprisingly, the enzymatic activity and nuclear localization of MdPDE1 are completely dependent on binding to PA.

There are two key PA-binding regions on the surface of the MdPDE1 protein: the KK-K domain (Lys112, Lys113, Lys166) and the KR-KR domain (Lys200, Arg201, Lys204, Arg205). When heat stress leads to PA accumulation, PA binds to these two regions, not only activating the enzymatic activity of MdPDE1 but also directing it into the nucleus.

This discovery breaks with the traditional concept of PA as a simple second messenger and shows that it is a signaling complex assembler and spatial positioning navigator of multiple functions.

5. Final-stage decoding of the signal in the core

Researchers found that a decrease in nuclear cAMP levels. To verify the specific role of cAMP regulation, the research team also designed an ingenious “cAMP sponge” experiment: expressing cAMP-binding protein in the cell nucleus specifically reduces nuclear cAMP levels. The results showed that even in the absence of MdPDE1, reducing nuclear cAMP could partially restore plant heat tolerance.

6. Field Validation: From the Laboratory to Farmland

Can theoretical research be translated into practical applications? The research team conducted a two-year field validation in a pilot field. They constructed a variety of transgenic rice lines: DGK7 overexpression, MdPDE1 overexpression, DGK7 overexpression in the context of TT2 knockout, etc. Under artificially simulated high-temperature conditions, these transgenic plants showed significant advantages:

• DGK7 overexpressing lines: Output increased by 66.72%-108.67%
• MdPDE1 overexpressing lines: Output increased by 64.91%-77.46%
• Pollen vitality is improved, and the chalkiness of the seeds is reduced

Most importantly, these genetic improvements Does not affect agronomic characteristics at normal temperature, truly achieving the breeding goal of “heat resistance without yield reduction”.

7. Technical Implications: The Importance of Precise Positioning

Looking back at the entire study, precise determination of protein subcellular localization is the basis for establishing credible signaling pathway models throughout.

During the early screening phase, the team realized that the whole “membrane to nuclear” signaling model would not hold if DGK7 were not on the cell membrane. Therefore, they chose a professional membrane protein separation method for validation. Modern plant signaling research is increasingly focusing on Cell space dimension, the dynamic distribution of proteins between different components, such as the membrane, plasma, and nucleus, often determines their functions. Accurate and efficient subcellular isolation technology has become a key support for this type of research.

The Invent spin column-based plant membrane protein extraction kit can separate plant cells into four components: nucleus (coarse extraction), cytoplasm, organelles, and cell membrane within 1 hour. It eliminates the need for ultra-high-speed centrifuges and homogenizing instruments to quickly separate the four natural components of protein from plant tissues. It can be applied downstream to SDS-PAGE, immunoblotting, ELISA, IP, Membrane protein structure analysis, 2-D, enzyme activity determination, and other applications.

Minute™ Plant Membrane Protein Extraction Kit SM-005-P

 

8. The complete picture of signaling pathways

Taking all the findings into account, the complete signaling pathways by which plants sense and respond to high temperatures are gradually becoming clear.

 

1. Perception on the membrane: High temperature causes membrane lipid remodeling and DAG accumulation
2. Signal conversion: DGK7 converts DAG into PA (regulated by TT2)
3. Signal transmission: PA binds to and activates MdPDE1, guiding it into the nucleus
4. In-core decoding: MdPDE1 degrades cAMP and promotes thermoresponsive gene expression
5. Physiological response: HSPs and antioxidant enzymes maintain cellular homeostasis and enhance heat tolerance

This  “Physical signals → lipid signals → second messengers → gene expression” The hierarchical decoding mechanism not only reveals the fine regulatory network of plant temperature perception, but also provides new ideas for crop improvement under climate change.