Biology subjects

Sugiura, D.

Publications and source records attributed to Sugiura, D..

6 recordsLinked to original sources

bioRxiv2026

Lotus japonicus CLV1-Like Receptor HAR1 Promotes Nitrogen Utilization and Growth Under Non-Symbiotic Conditions.

Legumes establish mutualistic symbiosis with nitrogen (N)-fixing bacteria, which allows them to utilize atmospheric N2. Because the maintenance of symbiosis requires abundant carbon (C) sources, legumes regulate the balance between carbon consumption and nitrogen acquisition by systemically controlling the nodule number through CLAVATA1 (CLV1)-like receptors. In Lotus japonicus, the CLV1-like receptor HYPERNODULATION ABERRANT ROOT FORMATION1 (HAR1) acts in shoots to regulate root nodulation and contributes to symbiotic C/N coordination. This raises the possibility that HAR1 may also influence plant growth and nitrogen utilization beyond symbiotic nodulation. In this study, we showed that HAR1 plays a critical role in regulating nitrogen use to enhance growth under conditions of high nitrate availability, even in non-symbiotic environments. Unlike the wild-type, the har1 mutant failed to increase its growth in response to higher nitrate availability. This lack of growth response was associated with a lower rate of net biomass production per unit leaf area and a reduced capacity for biomass production per unit plant nitrogen. We further found that nitrate-responsive TCA cycle-related organic acids were higher in har1 leaves than in wild-type leaves even under low nitrate conditions. Because the HAR1 mutation did not affect photosynthetic traits, we propose that HAR1 promotes growth under non-symbiotic conditions by coordinating nitrogen utilization with primary metabolism. One-sentence summaryLotus japonicus CLV1-like receptor HAR1 improves nitrogen utilization and growth at high nitrate conditions by regulating organic acid metabolism, independent of root nodule symbiosis.

plant biology↗

bioRxiv2024

Shoot nitrate status regulates Arabidopsis shoot growth and systemic transcriptional responses via shoot adenylate isopentenyltransferase 3

Plants systemically regulate growth and gene expression according to their internal nitrate status. Our previous study reported that shoot nitrate accumulation increases shoot expression of adenosine phosphate-ISOPENTENYLTRANSFERASE 3 (IPT3) and shoot levels of N6-({Delta}2-isopentenyl) adenine (iP)-type cytokinins (CKs). IPT3 expression is localized in the phloem, and iP-type CKs, which are synthesized by IPT3, are phloem-mobile. As CKs are a class of phytohormones that control growth and genome-wide gene expression, shoot-expressed IPT3 may mediate the systemic regulation of growth and transcriptomic responses to shoot nitrate status. To examine this, we developed a novel system to manipulate nitrate levels and IPT3 expression in a shoot-specific manner and performed growth analysis, CK determination, and RNA-sequencing. Our results demonstrated that shoot nitrate accumulation significantly promoted shoot growth and elevated shoot concentrations of iP ribotides, iP-7-N-glucoside, and iP-9-N-glucoside through the action of shoot IPT3. Transcriptomic responses to shoot nitrate accumulation were largely tuned by shoot IPT3, with opposite effects in shoots and roots. Shoot IPT3 amplified shoot responses of nitrate-inducible genes and immune response genes to shoot nitrate accumulation, while it dampened root responses of nitrate transport/assimilation genes. This transcriptomic modulation via shoot IPT3 was accompanied by coherent transcriptional changes in genes encoding mobile peptides and transcriptional repressors. Here we present a novel scheme integrating shoot nitrate status responses with CK signaling.

plant biology↗

bioRxiv2024

Morphological Plasticity and Reproductive Strategies of Kalanchoe Species in Invasive Spread

Kalanchoe species, originally introduced worldwide as ornamentals, are now reported to be spreading in many regions, including China. It is hypothesized that morphological plasticity and the production of asexual plantlets contribute to their successful invasion. To address the hypothesis, four species - Kalanchoe delagoensis Eckl. & Zeyh., Kalanchoe x houghtonii D. B. Ward, Kalanchoe laetivirens Desc. and Kalanchoe daigremontiana Raym. - Hamet & H. Perrier - were cultivated under contrasting light and water conditions, and their reproductive and vegetative traits were examined. The plants subjected to high light tended to prioritize plantlet production, accompanied by a reduction in vegetative growth. Two distinct reproductive strategies were observed: K. delagoensis and K. x houghtonii significantly increased plantlet production under high light conditions, whereas K. daigremontiana and K. laetivirens enhanced the fresh weight of individual plantlets without altering the total number produced. These results highlight the high plasticity of vegetative and reproductive growth in response to light and water availability. The increased production of plantlets may contribute to the widespread occurrence of Kalanchoe species in open fields.

plant biology↗

bioRxiv2023

Downregulation and delayed induction of photosynthesis by coordinated transcriptomic changes induced by sink-source imbalance

Understanding comprehensive mechanisms of the downregulation of photosynthesis induced by accumulation of non-structural carbohydrates (NSCs) is essential for the future food security.x Despite numerous studies, whether NSCs accumulation directly affects steady-state maximum photosynthesis and photosynthetic induction, as well as underlying gene expression profiles, remains unknown so far. We evaluated the relationship between photosynthetic capacity and NSCs accumulation induced by cold-girdling, sucrose feeding, and low nitrogen treatment in Glycine max and Phaseolus vulgaris. In G. max, changes in transcriptome profiles were further investigated focusing on physiological processes of photosynthesis and NSCs accumulation. NSCs accumulation decreased maximum photosynthetic capacity and delayed photosynthetic induction in both species. In G. max, such photosynthetic downregulation was explained by coordinated downregulation of photosynthetic genes involved in Calvin cycle, Rubisco activase, photochemical reactions, and stomatal opening. Furthermore, sink-source imbalance may have triggered a change in the balance of sugar-phosphate translocators in chloroplast membranes, which may have promoted starch accumulation in chloroplasts. Our findings provided an overall picture of the photosynthetic downregulation and NSCs accumulation in G. max, demonstrating that the photosynthetic downregulation is triggered by NSCs accumulation and cannot be explained simply by N deficiency. One Sentence SummaryAccumulation of nonstructural carbohydrates directly induced both downregulation and delayed induction of photosynthesis by coordinated transcriptomic changes in photosynthetic genes in Glycine max.

plant biology↗

bioRxiv2022

Root-specific activation of plasma membrane H+-ATPase 1 enhances plant growth and shoot accumulation of nutrient elements under nutrient-poor conditions in Arabidopsis thaliana

Plasma membrane (PM) H+-ATPase contributes to nutrient uptake and stomatal opening by creating proton gradient across the membrane. Previous studies report that a dominant mutation in the OPEN STOMATA2 locus (OST2-2D) constitutively activates Arabidopsis PM H+-ATPase 1 (AHA1), which enlarges proton motive force for root nutrient uptake. However, the stomatal opening is also constitutively enhanced in the ost2-2D, causing drought hypersensitivity. To develop plants with improved nutrient acquisition and normal stomatal movement, we generated grafted plants (scion/rootstock : Col-0 (WT)/ost2-2D), and compared their growth and nutrient element content with those of control plants (WT/WT) under two nutrient regimes. WT/ost2-2D shoots had larger weights, rosette diameter, leaf blade area, and content of C, N, K, Ca, S, P, Mg, Na, Mn, B, Co, and Mo under nutrient-poor conditions compared with WT/WT shoots. The root weights and primary root length were greater in WT/ost2-2D plants than in WT/WT plants under both nutrient conditions. These results suggest that root-specific activation of PM H+-ATPase enhances root nutrient uptake, which accelerates the plant growth under nutrient-poor condition. Our study presents a novel approach to improving nutrient uptake efficiency in crops and vegetable for the implementation of low-input sustainable agriculture.

plant biology↗

bioRxiv2021

Aboveground biomass increments over 26 years (1993-2019) in an old-growth cool-temperate forest in northern Japan

Assessing long-term changes in biomass of old-growth forests is critical in evaluating forest ecosystem functions under a changing climate. Long-term biomass changes are the result of accumulated short-term changes, which can be affected by endogenous processes such as gap filling in small-scale canopy openings. Here, we used 26 years (1993-2019) of repeated tree census data in an old-growth, cool-temperate, deciduous mixed forest that contains three topographic units (riparian, denuded slope, and terrace) in northern Japan to document decadal changes in aboveground biomass (AGB) and their processes in relation to endogenous processes and climatic factors. AGB increased steadily over the 26 years in all topographic units, but different tree species contributed to the increase among the topographic units. AGB gain within each topographic unit exceeded AGB loss via tree mortality in most of the measurement periods despite substantial temporal variation in AGB loss. At the local scale, variations in AGB gain were partially explained by compensating growth of trees around canopy gaps. Climate affected the local-scale AGB gain: the gain was larger in the measurement periods with higher mean temperature during the current summer but smaller in those with higher mean temperature during the previous autumn, synchronously in all topographic units. The decadal climate trends of warming are likely to have contributed to the steady increase in AGB in this old-growth forest.

ecology↗