Biology subjects

Betsuyaku, S.

Publications and source records attributed to Betsuyaku, S..

4 recordsLinked to original sources

bioRxiv2025

Unipolar polysaccharide-mediated attachment of the N2O-reducing bacterium Bradyrhizobium ottawaense SG09 to plant roots.

Agricultural soils are an important source of nitrous oxide (N2O), which has greenhouse and ozone-depleting effects. Bradyrhizobium ottawaense SG09 is a nitrogen-fixing rhizobium with high N2O-reducing activity. Rhizobia form symbiotic nodules in leguminous plants. The initial physical attachment of bacteria to plant roots is a critical step in the establishment of symbiotic interactions. In this study, we performed microscopic analysis using DsRed-expressing B. ottawaense SG09. We revealed that B. ottawaense SG09 attached to both the root surface and root hairs via single cellular poles. This polar attachment was observed not only to the symbiotic host soybean, but also to non-leguminous plants, such as Arabidopsis, rice, corn, and wheat. We identified and analyzed the unipolar polysaccharide (upp) gene cluster, which is proposed to be involved in polar attachment of rhizobia, in the genome of B. ottawaense SG09. We established an Arabidopsis-based interaction assay and demonstrated that uppC and uppE play a critical role in attachment to both the root surface and root hairs.

microbiology↗

bioRxiv2025

Systematic measurements of dose-dependent responses for combinatorial treatments of SA and JA led to the development of transcriptomic biomarkers

Plants coordinate defence against pathogens and herbivores through the crosstalk between salicylic acid (SA) and jasmonic acid (JA) signalling pathways. However, little is known about how plants integrate the phytohormone concentration profiles to shape defence states in complex field environments. Here we show that systematically varying combinatorial SA and JA concentrations in Arabidopsis thaliana reveals 43 distinct combination-specific transcriptional signatures beyond SA-JA antagonism. Leveraging these data, we developed and validated machine-learning-based transcriptomic biomarkers that enabled independent quantification of SA and JA response states. By applying these biomarkers to field-grown A. thaliana, we revealed that SA/JA response states were dynamically shaped by abundant and co-occurrence of herbivores on individual plants. Our study provides a strategy to decode hormonal responses to biotic environments from field transcriptomes, bridging the gap between molecular signalling and ecological dynamics.

plant biology↗

bioRxiv2021

Mechanosensory trichome cells evoke a mechanical stimuli-induced immune response in plants

Perception of pathogen-derived ligands by corresponding host receptors is a pivotal strategy in eukaryotic innate immunity. In plants, this is complemented by circadian anticipation of infection timing, promoting basal resistance even in the absence of pathogen threat. Here, we report that trichomes, hair-like structures on the epidermis, directly sense external mechanical forces caused by raindrops to anticipate waterborne infections in Arabidopsis thaliana. Exposure of leaf surfaces to mechanical stimuli initiates the concentric propagation of intercellular calcium waves away from trichomes to induce defence-related genes. Propagating calcium waves enable effective immunity against pathogenic microbes through the calmodulin-binding transcription activator 3 (CAMTA3) and mitogen-activated protein kinases. We propose a novel layer of plant immunity in which trichomes function as mechanosensory cells to detect potential risks.

plant biology↗

bioRxiv2021

An evolutionarily conserved coreceptor gene is essential for CLAVATA signaling in Marchantia polymorpha

Growth and development of land plants are controlled by CLAVATA3/EMBRYO SURROUNDING REGION-related (CLE) family of peptide hormones. In contrast to the genetic diversity of CLE family in flowering plants, the liverwort Marchantia polymorpha possesses a minimal set of CLE, MpCLE1(TDIF homolog) and MpCLE2 (CLV3 homolog). MpCLE1 and MpCLE2 peptides exert distinct function at the apical meristem of M. polymorpha gametophyte via specific receptors, MpTDIF RECEPTOR (MpTDR) and MpCLAVATA1 (MpCLV1), respectively, both belonging to the subclass XI of leucine-rich repeat receptor-like kinases (LRR-RLKs). Biochemical and genetic studies in Arabidopsis have shown that TDR/PXY family and CLV1/BAM family recognize the CLE peptide ligand in a heterodimeric complex with a member of subclass-II coreceptors. Here we show that three LRR-RLK genes of M. polymorpha are classified into subclass II, representing three distinct subgroups evolutionarily conserved in land plants. To address the involvement of subclass-II coreceptors in M. polymorpha CLE signaling, we performed molecular genetic analysis on one of them, MpCLAVATA3 INSENSITIVE RECEPTOR KINASE (MpCIK). Two knockout alleles for MpCIK formed narrow apical meristems marked by promMpYUC2:GUS marker, which were not expanded by MpCLE2 peptide treatment, phenocopying Mpclv1. Loss of sensitivity to MpCLE2 peptide was also observed in gemma cup formation in both Mpclv1 and Mpcik. Biochemical analysis using a Nicotiana benthamiana transient expression system revealed weak association between MpCIK and MpCLV1, as well as MpCIK and MpTDR. While MpCIK may also participate in MpCLE1 signaling, our data show that the conserved CLV3-CLV1-CIK module functions in M. polymorpha, controlling meristem activity for development and organ formation for asexual reproduction.

plant biology↗