Biology subjects

Isoda, R.

Publications and source records attributed to Isoda, R..

6 recordsLinked to original sources

bioRxiv2026

The Lateral Protein Cluster as a Key Component of Plant Cell Polarity

Cell polarity is an ancient organizing principle across kingdoms. As in animal epithelial cells, plant cells asymmetrically distribute proteins to establish functionally distinct membrane domains. In roots, radial polarity distinguishes inner and outer cell surfaces and supports directional nutrient transport, yet its molecular basis remains poorly understood. Here, we show that the leucine-rich repeat receptor-like kinases CaMRLK and IRK occupy complementary lateral plasma membrane domains in Arabidopsis thaliana roots. Polarity-guided proximity labeling identified previously uncharacterized proteins associated with inner- and outer-lateral domains. Clade VII LRR-RLKs, protein S-acyltransferases, SICK, IRKI1, and a distinct group of NPH3/RPT2-LIKEs assemble into the Lateral Protein Cluster (LPC) through multivalent interactions. LPC components are conserved across land plants, and disruption of NRL function impairs morphogenesis in Arabidopsis and Marchantia polymorpha. Together, these findings establish the LPC as an evolutionarily conserved molecular machinery linking radial cell polarity to plant morphogenesis.

plant biology↗

bioRxiv2023

Near-infrared imaging of phytochrome-derived autofluorescence in plant nuclei

Capturing images of the nuclear dynamics within live cells is an essential technique for comprehending the intricate biological processes inherent to plant cell nuclei. While various methods exist for imaging nuclei, including combining fluorescent proteins and dyes with microscopy, there is a dearth of commercially available dyes for live-cell imaging. In Arabidopsis thaliana, we discovered that nuclei emit autofluorescence in the near-infrared (NIR) range of the spectrum and devised a non-invasive technique for the visualization of live cell nuclei using this inherent NIR autofluorescence. Our studies demonstrated the capability of the NIR imaging technique to visualize the dynamic behavior of nuclei within primary roots, root hairs, and pollen tubes, which are tissues that harbor a limited number of other organelles displaying autofluorescence. We further demonstrated the applicability of NIR autofluorescence imaging in various other tissues by incorporating fluorescence lifetime imaging techniques. Nuclear autofluorescence was also detected across a wide range of plant species, enabling analyses without the need for transformation. The nuclear autofluorescence in the NIR wavelength range was not observed in animal or yeast cells. Genetic analysis revealed that this autofluorescence was caused by the phytochrome protein. Our studies demonstrated that nuclear autofluorescence imaging can be effectively employed not only in model plants but also for studying nuclei in non-model plant species.

plant biology↗

bioRxiv2022

Imbalance of circuit plasticity and consolidation in autism model marmosets is adjusted by oxytocin administration

Alterations in the experience-dependent and autonomous elaboration of neural circuits are assumed to underlie autism spectrum disorder (ASD), though it is unclear what synaptic traits are responsible. Here, we used a valproic acid-induced ASD marmoset model, which shares common molecular features with idiopathic ASD, to investigate the structural dynamics of tuft dendrites of upper-layer pyramidal neurons and adjacent axons in the dorsomedial prefrontal cortex using two-photon microscopy. In model marmosets, dendritic spine turnover was upregulated, and spines were actively generated in clusters and subsequently survived more often than in control marmosets. Presynaptic boutons in local axons but not in commissural long-range axons showed hyperdynamic turnover in model marmosets, suggesting alterations in projection-specific plasticity. Intriguingly, nasal administration of oxytocin reduced the clustered spine emergence. Enhanced clustered spine generation, possibly unique to certain presynaptic partners, may be associated with ASD and may be a potential therapeutic target.

neuroscience↗

bioRxiv2022

SWEET13 transport of sucrose, but not gibberellin, restores male fertility in Arabidopsis sweet13;14

SWEET sucrose transporters play important roles in the allocation of sucrose in plants. Some SWEETs were shown to also mediate transport of the plant growth regulator gibberellin (GA). The close physiological relationship between sucrose and GA raised the questions of if there is a functional connection, and whether one or both of the substrates are physiologically relevant. To dissect these two activities, molecular dynamics were used to map the binding sites of sucrose and GA in the pore of SWEET13 and predicted binding interactions that might be selective for sucrose or GA. Transport assays confirmed these predictions. In transport assays, the N76Q mutant had 7x higher relative GA3 activity, and the S142N mutant only transported sucrose. The impaired pollen viability and germination in sweet13;14 double mutants were complemented by the sucrose-selective SWEET13S142N but not by the SWEET13N76Q mutant, indicating that sucrose is the physiologically relevant substrate and that GA transport capacity is dispensable in the context of male fertility. Therefore, GA supplementation to counter male sterility may act indirectly via stimulating sucrose supply in male sterile mutants. These findings are also relevant in the context of the role of SWEETs in pathogen susceptibility.

plant biology↗

bioRxiv2021

OsSWEET11b, a sixth leaf blight susceptibility gene involved in sugar transport-dependent male fertility

SWEETs play important roles in intercellular sugar transport. Induction of SWEET sugar transporters by transcription activator-like effectors (TALe) of Xanthomonas ssp. is a key factor for bacterial leaf blight (BLB) infection of rice, cassava and cotton. Here, we identified the so far unknown OsSWEET11b with roles in male fertility and BLB susceptibility in rice. While single ossweet11a or b mutants were fertile, double mutants were sterile. Since clade III SWEETs can transport gibberellin (GA), a key hormone for rice spikelet fertility, sterility and BLB susceptibility might be explained by GA transport deficiencies. However, in contrast to the Arabidopsis homologs, OsSWEET11b did not mediate detectable GA transport. Fertility and susceptibility must therefore depend on SWEET11b-mediated sucrose transport. Ectopic induction of OsSWEET11b by designer TALe enables TALe-free Xanthomonas oryzae pv. oryzae (Xoo) to cause disease, identifying OsSWEET11b as a BLB susceptibility gene and demonstrating that the induction of host sucrose uniporter activity is key to virulence of Xoo. Notably, only three of now six clade III SWEETs are targeted by known Xoo strains from Asia and Africa. The identification of OsSWEET11b has relevance in the context of fertility and for protecting rice against emerging Xoo strains that evolve TALes to exploit OsSWEET11b.

plant biology↗

bioRxiv2020

Distinct synaptic and related transcriptional abnormalities in neonatal, childhood and mature autism model of primate: implications for early-age therapeutic intervention

Autism spectrum disorder (ASD) is a synapse-related disorder that is diagnosed at around 3 years of age. Earlier intervention is desirable for better ASD prognosis; however, there is limited biological literature regarding early-age ASD. This study aimed to assess altered cortical synapses and gene expression in the ASD model marmoset. There were distinct phenotypes in the model animals across the neonate, childhood, and mature stages in the dorsomedial prefrontal cortex (Brodmann area 8b/9). At the neonate stage, synapses were underdeveloped and modulated genes were enriched with synaptogenesis- and ASD-related genes. At the childhood stage, synaptic features and gene expressions associated with experience-dependent circuit remodeling were altered in model animals. At the mature stage, there were synapse overdevelopment and altered gene expression similar to those in human ASD. These early synaptic phenotypes and altered gene expressions could be novel targets of efficient therapy from a young age.

neuroscience↗