Biology subjects

Bessho-Uehara, K.

Publications and source records attributed to Bessho-Uehara, K..

3 recordsLinked to original sources

bioRxiv2025

Brassinosteroids promote sugar synthesis by inhibiting BIN2 phosphorylation of phosphoenolpyruvate carboxykinase

Sugar is both an essential energy source and the major substrate for cell wall biosynthesis during plant growth, yet how growth-promoting hormones regulate sugar synthesis remains unclear. Here, we show that the brassinosteroids (BRs) promote gluconeogenic and photosynthetic sugar synthesis by activating phosphoenolpyruvate carboxykinase (PCK), which catalyzes the conversion of oxaloacetate to phosphoenolpyruvate, a central step in primary metabolism. Arabidopsis BR-deficient mutants display reduced PCK1 activity and elevated phosphorylation at conserved Ser-62 and Thr-66 residues. BR treatment induces PCK1 dephosphorylation and activation, whereas the GSK3-like kinase BIN2 phosphorylates these sites, altering quaternary structure and inhibiting PCK1. Phospho-blocking mutations of Ser-62/Thr-66 confer BR-independent PCK1 activity and enhance seedling growth, while phosphomimetic mutations reduce PCK1 activity and impair seedling growth and establishment. BR also promotes PCK dephosphorylation and activation in photosynthetic leaves of maize and sorghum. Our study demonstrates that BR regulates primary metabolism via GSK3/BIN2-mediated phosphorylation of PCK, thereby promoting gluconeogenesis and photosynthesis.

plant biology↗

bioRxiv2025

Citizen science data indicates morphological complexity of galls depends on the originating plant organ

Galls are abnormal plant structures formed through interactions between host plants and insects, providing shelter and nutrients for gall-inducing insects. As distinct insect species can generate unique gall morphologies even on the same host plant, galls are often viewed as an extended phenotype of the insect. However, since galls consist of plant-derived cells, plant factors are also hypothesized to shape their morphology. Previous studies exploring this possibility have been restricted to one or a few plant species, limiting broad evolutionary inference. Here, we used citizen science observations to analyze gall morphological complexity across 26 plant orders. Quantitative comparisons using fractal dimension indices revealed that stem-derived galls display significantly less morphological variation than leaf-derived galls. Generalized linear mixed models indicated that stems possess lower morphological plasticity than leaves. These results held even after accounting for insect and plant phylogeny, suggesting that gall form is influenced by both insect species and the developmental properties of the host organ. Our findings highlight the role of plant organ identity in modulating gall morphology and demonstrate that tissue plasticity constrains insect-induced developmental outcomes. This study provides the large-scale cross-species analysis of gall formation and illustrates the power of citizen science in studying morphological evolution across taxa.

plant biology↗

bioRxiv2024

Parasitic-plant parasite utilizes flowering pathways at unconventional stages to form stem-derived galls

Galls induced by various organisms exhibit diverse morphological and physiological characteristics, involving complex plant-insect interactions. Most transcriptome analyses to date have focused on leaf-derived galls. To better understand gall formation mechanisms, we investigated stem-derived galls induced by the weevil Smicronyx madaranus on the parasitic plant Cuscuta campestris at gene expression, cellular, and physiological levels. RNA-seq across four developmental stages identified differentially expressed genes and associated gene ontology terms. Consistent with histological observations, genes related to cell division and the cell cycle were upregulated early but decreased as the gall matured. Similar to leaf-derived galls, we found high expression of PLETHORA and meristem-related homeobox genes in early gall development, suggesting that stem cell induction and maintenance are involved in various gall types. Like leaf- derived galls, the expression of genes related to floral organ development increased through the gall development. However, their expression patterns were dramatically different: downstream genes in the flowering pathway were highly expressed at the initial gall stage, whereas upstream genes were highly expressed later. This suggests that the weevil might activate the flowering pathway at unconventional stages, potentially rerouting the typical flowering cascade to influence gall development. Unlike the decrease in photosynthesis-related genes in leaf-derived galls, we observed an increase in these genes in galls formed on the stem of the holoparasitic plant. Shading experiments confirmed that photosynthesis is crucial for both gall growth and the weevil. This study highlights how gall-inducers can co-opt host resources and genetic pathways, offering new insights into the complexity of plant-insect interactions.

plant biology↗