📄 plant biology

Inherited proliferation states organize plant transcriptomes

This study reveals that inherited genetic programs, specifically a conserved proliferation transcriptional state regulated by discrete loci, are the primary organizers of global plant transcriptome variation across species, outweighing the influence of environmental adaptation.

Original authors: Lee, C., Lee, S., Gwon, D., Razzaque, S., Jeong, H., Busch, W., Michael, T. P., Lee, S.

Published 2026-07-14

📖 5 min read🧠 Deep dive

CC BY 4.0

Original authors: Lee, C., Lee, S., Gwon, D., Razzaque, S., Jeong, H., Busch, W., Michael, T. P., Lee, S.

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ⚕️ This is an AI-generated explanation of a preprint that has not been peer-reviewed. It is not medical advice. Do not make health decisions based on this content. Read full disclaimer

Imagine you have a massive library of 665 different plant families (called Arabidopsis thaliana accessions), each living in a slightly different spot on Earth. For a long time, scientists thought that if you looked at the "instruction manuals" inside these plants (their transcriptomes), the biggest differences would be caused by the weather. They assumed a plant in a hot, dry desert would have a totally different manual than a plant in a cool, wet forest, just because they were reacting to their immediate surroundings.

But this paper flips that idea on its head. The authors discovered that where a plant's ancestors came from matters way more than the weather it's currently experiencing.

The Great Identity Crisis: Weather vs. Family Tree

The researchers ran a massive test to see what actually organizes these plant instruction manuals. They compared two things:

The Environment: The temperature, rain, and soil of where the plant is growing right now.
The Family History: The genetic background and population structure of the plant.

The results were shocking. The environment alone explained only 2.5% of the differences in the plants' gene activity. In contrast, the plant's genetic history explained a whopping 30.0% of the variation.

Think of it like this: If you walked into a room of 665 people, you could guess what they were wearing based on the weather outside, but you'd be way better at guessing their family traditions and genetic quirks just by looking at them. The plants' "genetic family tree" is the primary architect of their internal biology, not the current climate.

The "ProlifME" Engine

So, what is this massive genetic influence actually doing? The authors found that the plants' gene activity is dominated by a single, giant co-expression program they named prolifME (short for "proliferation Module Eigengene").

Imagine the plant's cells are a busy factory. prolifME is the master switch that turns on the assembly lines for two specific things:

Cell Division: Making new cells.
Ribosome Biogenesis: Building the machines that make proteins.

This isn't just a random list of genes; it's a coordinated "growth engine" involving 10,736 genes (about 45% of the plant's entire transcriptome). It's like finding that 45% of the factory's workers are all synchronized to the same rhythm, regardless of whether it's raining or sunny outside.

The Growth-Defense Trade-Off

Here is where it gets interesting for the plants' survival. The paper shows that plants with a "loud" prolifME engine (high activity) tend to be smaller. They grow faster in terms of cell division but end up with less total biomass, slower overall growth rates, and lower water-use efficiency.

It's a classic trade-off: You can either spend your energy building a massive, sturdy fortress (defense) or you can spend it frantically building new rooms and expanding the factory (proliferation). The plants with high prolifME activity chose the "expand fast" strategy, which ironically made them smaller and less efficient at holding water. This pattern held true even when the plants were all grown in the exact same garden, proving it's a built-in genetic strategy, not just a reaction to the weather.

The "Deep Time" Connection

The most mind-bending part? This isn't just a quirk of Arabidopsis. The researchers looked at rice and maize (corn), plants that split from Arabidopsis 150–200 million years ago.

They found that the specific genes contributing to this "growth engine" in Arabidopsis are conserved in rice and maize. It's as if the blueprint for this specific factory rhythm was written so long ago that even though the buildings (the plants) look totally different now, the internal rhythm of the assembly lines is still humming to the same beat.

What the Paper Rules Out

It is crucial to note what this study says is not the main driver. The authors explicitly rule out the idea that current environmental gradients (like temperature or soil type) are the primary organizers of the global transcriptome architecture. While the environment does matter a little bit (that 2.5%), it is negligible compared to the massive signal of population history.

They also clarify that this isn't just a "housekeeping" effect. Even after removing the genes responsible for basic ribosome function, the structure of this program remained intact. It's a specific, organized biological program, not just a generic "I'm alive" signal.

How Sure Are They?

The authors are very confident in these findings because they used rigorous statistical methods.

They measured the variance and found that genomic population structure uniquely explains 30.0% of the variation, while environment explains only 2.5%.
They tested this across 665 natural accessions.
They confirmed the results in a "common garden" experiment where all plants grew in the same spot, proving the differences were genetic, not environmental.
They used permutation tests (random shuffling) to show that the conservation between species is statistically significant (p < 1e-300), meaning it's virtually impossible this happened by chance.

In short, the paper suggests that the "personality" of a plant's gene expression is inherited from its ancestors and locked into a specific growth strategy, rather than being a flexible response to the weather outside. It's a fundamental, intrinsic state that has been conserved across hundreds of millions of years of evolution.

Technical Summary: Inherited proliferation states organize plant transcriptomes

Problem and Motivation
A central question in plant biology concerns the primary drivers of natural transcriptome variation: does it reflect environmental adaptation or intrinsic genetic programs? While previous studies have linked gene expression to local climate and environmental gradients (e.g., Des Marais and Juenger 2010; Lasky et al. 2012), it remains unresolved whether intrinsic, genetically encoded constraints organize global transcriptome architecture across natural populations. In other biological systems, such as yeast and the human brain, transcriptome organization is known to reflect intrinsic biological constraints (Gasch et al. 2000; Oldham et al. 2008). This study investigates whether a similar intrinsic program dominates the transcriptome variation in natural Arabidopsis thaliana populations, distinguishing it from environmental plasticity.

Methodology
The authors integrated multi-omics data from 665 natural A. thaliana accessions from the 1001 Genomes Project. The dataset included:

Transcriptomics: Genome-wide RNA-seq profiles.
Genomics: Whole-genome SNP data to derive genomic principal components (genomicPC1–10) representing population structure.
Environment: Climate variables (WorldClim v2.1, 19 BIO variables) and soil properties (SoilGrids).
Phenotypes: Growth and physiological traits from AraPheno and common garden experiments.

Key analytical steps included:

Variance Partitioning: Using ridge regression and cross-validation (CV-R²) to quantify the unique and shared contributions of environmental predictors versus genomic population structure to transcriptome variation (ExprPC1–10). A circadian expression proxy (ClockPC1) was included as a covariate to control for sampling time artifacts.
Co-expression Network Analysis: Weighted Gene Co-expression Network Analysis (WGCNA) was performed to identify dominant co-expression modules. The largest module was characterized for functional enrichment (Gene Ontology) and promoter motif analysis (E2F, TCP class I, Telobox).
Genetic Basis: Genome-wide association studies (GWAS) were conducted using the module eigengene as a quantitative trait, followed by trans-eQTL analysis to identify loci with broad regulatory effects.
Phenotypic Association: Partial regression analyses assessed the relationship between the dominant module and growth-strategy phenotypes (plant size, biomass, growth rate, water-use efficiency), controlling for population structure and geography.
Cross-Species Conservation: Gene contributions to the identified module were projected onto orthologous genes in rice (Oryza sativa) and maize (Zea mays) to test for conservation of the proliferation program across 150–200 million years of divergence.

Key Results

Population History Dominates Transcriptome Architecture: Genomic population structure uniquely explains 30.0% of transcriptome-wide variation, whereas environmental variables account for only 2.5%. While environmental gradients explain more variation within geographically restricted subsets, population history is the primary organizer of global transcriptome variation across the full diversity of A. thaliana.
Identification of the Proliferation Module (prolifME): The dominant axis of population-structured variation is captured by a single co-expression module, prolifME, comprising 10,736 genes (~45% of the expressed transcriptome). This module is enriched for cell cycle regulation and ribosome biogenesis. Its regulatory architecture is bipartite: E2F motifs are enriched in cell cycle gene promoters, while TCP class I and Telobox motifs are enriched in ribosome gene promoters.
Genetic Encoding and Trans-Regulation: GWAS identified four independent loci associated with prolifME eigengene variation. These loci exhibit significant trans-regulatory effects, influencing thousands of genes within the module. Candidate genes at these loci (e.g., GRF2, RPT3) are themselves members of prolifME, suggesting that natural variation in module activity arises from genetic variation within the module's components.
Phenotypic Correlations: Higher prolifME activity is associated with reduced plant size, reduced rosette dry mass, reduced growth rate, and reduced water-use efficiency (lower $\delta^{13}$ C). These associations persist in common garden experiments and controlled greenhouse conditions, indicating they reflect an intrinsic, genetically encoded growth strategy rather than plastic environmental responses. A negative correlation with defense-related modules (defenseME) suggests a transcriptome-level growth-defense trade-off.
Cross-Species Conservation: The relative contribution of genes to the proliferation program is significantly conserved in rice ( $r=0.292$ ) and maize ( $r=0.178$ ). This conservation reflects the co-expression structure of the proliferation axis, which remains organized similarly across plant lineages separated by 150–200 million years.

Significance and Claims
The paper claims to identify an intrinsic transcriptional proliferation program as a primary state of plant population transcriptomes. The findings suggest that knowing a plant's genetic ancestry (population history) predicts its global expression profile significantly better than knowing its current environment. The study establishes that plant population transcriptomes are organized primarily by an intrinsic proliferation program involving cell cycle and ribosome biogenesis, which is conserved across diverse plant species. This provides a framework for understanding the relationship between genetic ancestry, environment, and transcriptome architecture, highlighting that global transcriptome variation may be more informative about evolutionary history than immediate ecological conditions. The authors note that while individual genes respond to the environment, the global scaffold of variation is shaped by this conserved, intrinsic biological program.