Morphogenesis requires the coordination of cellular behaviors along developmental axes. In plants, gradients of growth and differentiation are typically established along a single longitudinal primordium axis to control global organ shape. Yet, it remains unclear how these gradients are locally adjusted to regulate the formation of complex organs that consist of diverse tissue types. Here we combine quantitative live imaging at cellular resolution with genetics, and chemical treatments to understand the formation of Arabidopsis thaliana female reproductive organ (gynoecium). We show that, contrary to other aerial organs, gynoecium shape is determined by two orthogonal, time-shifted differentiation gradients. An early mediolateral gradient controls valve morphogenesis while a late, longitudinal gradient regulates style differentiation. Local, tissue-dependent action of these gradients serves to fine-tune the common developmental program governing organ morphogenesis to ensure the specialized function of the gynoecium.

Plant organs have evolved into diverse shapes for specialized functions despite emerging as simple protrusions at the shoot apex. Cauline leaves serve as photosynthetic organs and protective structures for emerging floral buds. However, the growth patterns underlying this dual function remain unknown. Here, we investigate the developmental dynamics shaping Arabidopsis (Arabidopsis thaliana) cauline leaves underlying their functional diversification from other laminar organs. We show that cauline leaves display a significant delay in overall elongation compared to rosette leaves. Using live imaging, we reveal that their functional divergence hinges on early modulation of the timing of cell differentiation and cellular growth rates. In contrast to rosette leaves and sepals, cell differentiation is delayed in cauline leaves, fostering extended proliferation, prolonged morphogenetic activity, and growth redistribution within the organ. Notably, cauline leaf growth is transiently suppressed during the early stages, keeping the leaf small and unfolded during the initiation of the first flowers. Our findings highlight the unique developmental timing of cauline leaves, underlying their shift from an early protective role to a later photosynthetic function.

Summary: Plant development depends on coordinated growth at cellular and organ scales, yet comparative analyses are hindered by inconsistent reporting of growth across studies. We conducted a meta‐analysis of Arabidopsis thaliana growth dynamics, integrating data from 176 studies to create the first multiscale atlas of plant growth. We developed a unified mathematical framework to harmonise growth data from diverse organs (shoot apical meristem, root, hypocotyl, and leaf), methodologies, and experimental setups, allowing the conversion and direct comparison of expansion rates at cellular and organ levels. Analyses revealed both organ‐specific and general growth strategies linked to size control. In the meristem, a conserved offset in cell expansion between central and peripheral zones was observed. Root elongation was driven mainly by cell expansion and differentiation in the elongation zone, rather than meristem activity. Hypocotyl and leaf growth showed unexpected parallels: early exponential elongation resembled primary morphogenesis, while later linear growth matched secondary morphogenesis. Comparing dark‐ vs light‐grown hypocotyls and juvenile vs transition leaves showed that organ size was modulated by a trade‐off between growth rate and duration of the scaling phase. Cellular‐scale growth during early development was shown to influence final organ size, underscoring the need for early‐stage measurements. This growth atlas provides benchmark values and a reference framework for interpreting mutant phenotypes, guiding experimental design, and advancing our understanding of growth regulation across plant organs.

Morphogenesis requires the coordination of cellular behaviors along developmental axes ¹ . In plants, gradients of growth and differentiation are typically established along a single longitudinal primordium axis to control organ shaping ² . Here we combine quantitative live-imaging at cellular resolution with genetics, chemical treatments, and modeling to understand the formation of Arabidopsis thaliana female reproductive organ (gynoecium). We show that, contrary to other aerial organs, gynoecium shape is determined by two competing differentiation gradients positioned along two orthogonal axes. An early mediolateral gradient, dependent on meristematic activity in the medial domain, controls the valve morphogenesis while simultaneously restricting an auxin-dependent, longitudinal gradient to the style. This gradient competition serves to finetune the common developmental program governing organ morphogenesis to ensure the specialized function of the gynoecium ^3,4 .

The glyoxalase pathway intermediate S-d-lactoylglutathione was recently implicated in protein post-translational modifications in animal systems. Here, we examined the spontaneous modification of the Arabidopsis thaliana cytosolic glyceraldehyde-3-phosphate dehydrogenase C1 (GAPC1) by this compound. Incubation of GAPC1 with S-d-lactoylglutathione resulted in the inhibition of enzyme activity. The inhibitory effect was concentration dependent and increased at alkaline pHs. Furthermore, the inhibition of GAPC1 by S-d-lactoylglutathione was favored by oxidative conditions and reversed by reduction with dithiothreitol. Analyses of the S-d-lactoylglutathione-treated protein by nanoLC-MS/MS revealed S-glutathionylation of its two Cys residues and N-lactoylation of six Lys residues. Protein structure predictions showed that the double S-glutathionylation is accommodated by the GAPC1 catalytic pocket, which likely explains enzyme inhibition. N-lactoylated sites overlap partially with previously reported N-acetylated sites at the surface of the GAPC1 tetramer. The efficiency of cytosolic glutaredoxin and thioredoxin isoforms was tested for reversing the S-d-lactoylglutathione-induced modification. In these assays, recovery of GAPC1 activity after inhibition by S-d-lactoylglutathione treatment was used as indicator of efficiency. The results show that both types of redoxins were able to reverse inhibition. We propose a model describing the mechanisms involved in the two types of post-translational modifications found on GAPC1 following exposure to S-d-lactoylglutathione. The possible involvement of these findings for the control over glycolytic metabolism is discussed.

In this study, the involvement of S,D-lactoylglutathione in the modification of the iso-form 1 of cytosolic glyceraldehyde 3P dehydrogenase (GAPC1) is examined. Incuba-tion of GAPC1 with S,D-lactoylglutathione resulted in inhibition of enzyme activity. The inhibitory effect was concentration-dependent and increased at alkaline pHs. Furthermore, inhibition of GAPC1 by S,D-lactoylglutathione was favored by oxidative conditions and reversed by reduction with dithiothreitol. Analyses of the S,D-lactoylglutathione-treated protein by nano LC-MS/MS revealed S-glutathionylation of its two Cys residues and N-lactoylation of six Lys residues. Pro-tein structure prediction showed that the double S-glutathionylation is accommodated by the GAPC1 catalytic pocket which likely explains enzyme inhibition. N-lactoylated sites overlap partially with previously reported N-acetylated sites at the surface of the GAPC1 tetramer. The efficiency of cytosolic glutaredoxin and thioredoxin isoforms was tested for reversing the S,D-lactoylglutathione-induced modification. In these as-says, recovery of GAPC1 activity after inhibition by S,D-lactoylglutathione treatment was used as indicator of efficiency. Results show that both types of redoxins were able to reverse inhibition. We propose a model describing the mechanisms involved in the two types of post-translational modification found on GAPC1 following exposure to S,D-lactoylglutathione. The possible involvement of these findings for the control over glycolytic metabolism is discussed.