Large-scale single-cell profiling of stem cells identifies redundant regulators of shoot development and yield trait variation.

Plant shoot stem cells generate organs essential for food, feed, and biofuels. However, plant single-cell analyses struggled to capture these rare cells or to detect stem cell regulators like CLAVATA3 and WUSCHEL. Here, we dissected stem cell-enriched shoot tissues from maize and Arabidopsis for single-cell RNA sequencing (scRNA-seq), and we optimized protocols to recover thousands of CLAVATA3- and WUSCHEL-expressing cells.

A cytokinin response maximum induces and activates bifacial stem cells for radial growth.

Wood is formed as plants expand in thickness through radial growth, which initiates after apical growth. At the onset of radial growth, dormant procambial cells in the vasculature become active and act as bifacial cambium stem cells, which produce xylem (wood) inward and phloem outward. Cytokinin has been implicated in radial growth initiation; however, its precise mechanisms, especially at the cellular level, remain unclear.

Spatiotemporal localization of jasmonate in the regulation of fruit set in tomato.

Tomato (Solanum lycopersicum) is a globally important crop, typically requiring pollination for fruit set. Seedless fruit production-fruit set without pollination (parthenocarpy)-is a desirable trait for horticulture, though its molecular mechanisms are not fully understood. Research on tomato fruit set has largely focused on phytohormones like auxin and gibberellins (GAs), while the role of jasmonic acid (JA) remains unclear.

Spatio-Temporal Regulation of Gibberellin Biosynthesis Contributes to Optimal Rhizome Bud Development.

The perennial life cycle involves the reiterative development of sexual and asexual organs. Asexual structures such as rhizomes are found in various plant species, fostering extensive growth and competitive advantages. In the African wild rice Oryza longistaminata, we investigated the formation of rhizomes from axillary buds, which notably bend diagonally downward of the main stem, as the factors determining whether axillary buds become rhizomes or tillers are unclear.

Multi-omics signatures of diverse plant callus cultures.

Callus cultures are fundamental for plant propagation, genetic transformation, and emerging biotechnological applications that use cellular factories to produce high-value metabolites like plant-based drugs. These applications exploit the diverse metabolic capabilities of various plant species. However, optimizing culture conditions for specific applications necessitates a deep understanding of the transcriptome, metabolome, and phytohormone profiles of different species.

Multiomics-based assessment of the impact of airflow on diverse plant callus cultures.

Plant cell culture has multiple applications in biotechnology and horticulture, from plant propagation to the production of high-value biomolecules. However, the interplay between cellular diversity and ambient conditions influences the metabolism of cultured tissues; understanding these factors in detail will inform efforts to optimize culture conditions. This study presents multiomics datasets from callus cultures of tobacco (Nicotiana tabacum), rice (Oryza sativa), and two bamboo species (Phyllostachys nigra and P.

KAI2-dependent signaling controls vegetative reproduction in Marchantia polymorpha through activation of LOG-mediated cytokinin synthesis (14).

Marchantia polymorpha reproduces vegetatively (asexually) by producing propagules known as gemmae within gemma cups and sexually through spores. We previously reported that KARRIKIN INSENSITIVE2 (KAI2)-dependent signaling promotes gemma cup and gemma formation. KAI2A perceives unidentified endogenous ligand(s), tentatively referred to as KAI2 ligands (KL).

Chloroplast arrangement in finger millet under low-temperature conditions.

Background: Finger millet, a C plant with mesophyll and bundle sheath cells, has been cultivated at high altitudes in the Himalayas owing to its adaptability to stressful environments. Under environmental stresses such as high light and drought, finger millet mesophyll chloroplasts move toward the bundle sheath, a phenomenon known as aggregative arrangement.

Methods: To investigate the effect of low temperatures on mesophyll chloroplast arrangement in finger millet, we conducted microscopic observations and photochemical measurements using leaves treated at different temperatures in light or darkness, with or without pharmacological inhibitors.

The cytokinin efflux transporter ABCC4 participates in Arabidopsis root system development.

The directional and sequential flow of cytokinin in plants is organized by a complex network of transporters. Genes involved in several aspects of cytokinin transport have been characterized; however, much of the elaborate system remains elusive. In this study, we used a transient expression system in tobacco (Nicotiana benthamiana) leaves to screen Arabidopsis (Arabidopsis thaliana) transporter genes and isolated ATP-BINDING CASSETTE TRANSPORTER C4 (ABCC4).

Periodic cytokinin responses in rhizobium infection and nodule development.

Host plants benefit from legume root nodule symbiosis with nitrogen-fixing bacteria under nitrogen-limiting conditions. In this interaction, the hosts must regulate nodule numbers and distribution patterns to control the degree of symbiosis and maintain root growth functions. The host response to symbiotic bacteria occurs discontinuously but repeatedly at the region behind the tip of the growing roots.

Plant hormone profiling of scion and rootstock incision sites and intra- and inter-family graft junctions in .

Many previous studies have suggested that various plant hormones play essential roles in the grafting process. In this study, to understand the plant hormones that accumulate in the graft junctions, whether these are supplied from the scion or rootstock, and how these hormones play a role in the grafting process, we performed a hormonome analysis that accumulated in the incision site of the upper plants from the incision as "ungrafted scion" and lower plants from the incision as "ungrafted rootstock" in . The results revealed that indole-3-acetic acid (IAA) and gibberellic acid (GA), which regulate cell division; abscisic acid (ABA) and jasmonic acid (JA), which regulate xylem formation; cytokinin (CK), which regulates callus formation, show different accumulation patterns in the incision sites of the ungrafted scion and rootstock.

A cell wall-localized cytokinin/purine riboside nucleosidase is involved in apoplastic cytokinin metabolism in .

In the final step of cytokinin biosynthesis, the main pathway is the elimination of a ribose-phosphate moiety from the cytokinin nucleotide precursor by phosphoribohydrolase, an enzyme encoded by a gene named LONELY GUY (LOG). This reaction accounts for most of the cytokinin supply needed for regulating plant growth and development. In contrast, the LOG-independent pathway, in which dephosphorylation and deribosylation sequentially occur, is also thought to play a role in cytokinin biosynthesis, but the gene entity and physiological contribution have been elusive.

Phosphate starvation response precedes abscisic acid response under progressive mild drought in plants.

Drought severely damages crop production, even under conditions so mild that the leaves show no signs of wilting. However, it is unclear how field-grown plants respond to mild drought. Here, we show through six years of field trials that ridges are a useful experimental tool to mimic mild drought stress in the field.

The trans-zeatin-type side-chain modification of cytokinins controls rice growth.

Cytokinins (CKs), a class of phytohormones with vital roles in growth and development, occur naturally with various side-chain structures, including N6-(Δ2-isopentenyl)adenine-, cis-zeatin- and trans-zeatin (tZ)-types. Recent studies in the model dicot plant Arabidopsis (Arabidopsis thaliana) have demonstrated that tZ-type CKs are biosynthesized via cytochrome P450 monooxygenase (P450) CYP735A and have a specific function in shoot growth promotion. Although the function of some of these CKs has been demonstrated in a few dicotyledonous plant species, the importance of these variations and their biosynthetic mechanism and function in monocots and in plants with distinctive side-chain profiles other than Arabidopsis, such as rice (Oryza sativa), remain elusive.

Identification of a pluripotency-inducing small compound, PLU, that induces callus formation Heat Shock Protein 90-mediated activation of auxin signaling.

Plants retain the ability to generate a pluripotent tissue called callus by dedifferentiating somatic cells. A pluripotent callus can also be artificially induced by culturing explants with hormone mixtures of auxin and cytokinin, and an entire body can then be regenerated from the callus. Here we identified a pluripotency-inducing small compound, PLU, that induces the formation of callus with tissue regeneration potency without the external application of either auxin or cytokinin.

Comprehensive analyses of plant hormones in etiolated pea and maize seedlings grown under microgravity conditions in space: Relevance to the International Space Station experiment "Auxin Transport".

Functional relationships between endogenous levels of plant hormones in the growth and development of shoots in etiolated Alaska pea and etiolated Golden Cross Bantam maize seedlings under different gravities were investigated in the "Auxin Transport" experiment aboard the International Space Station (ISS). Comprehensive analyses of 31 species of plant hormones of pea and maize seedlings grown under microgravity (μg) in space and 1 g conditions were conducted. Principal component analysis (PCA) and a multiple regression analysis with the dataset from the plant hormone analysis of the etiolated pea seedlings grown under μg and 1 g conditions in the presence and absence of 2,3,5-triiodobenzoic acid (TIBA) revealed endogenous levels of auxin correlated positively with bending and length of epicotyls.

Plant Hormone and Inorganic Ion Concentrations in the Xylem Exudate of Grafted Plants Depend on the Scion-Rootstock Combination.

In grafted plants, inorganic ions and plant hormones in the xylem exudate transported from the rootstock to the scion directly or indirectly affect the scion, thereby improving the traits. Therefore, the concentration of these components in the xylem exudate of grafted plants may be an indicator for rootstock selection. On the other hand, few reports have presented a comprehensive analysis of substances transferred from the rootstock to the scion in plants grafted onto different rootstocks, primarily commercial cultivars.

ABCG11 modulates cytokinin responses in .

The Arabidopsis ABC transporter ABCG11 transports lipidic precursors of surface coating polymers at the plasma membrane of epidermal cells. Mutants in exhibit severe developmental defects, suggesting that ABCG11 might also participate in phytohormone-mediated development. Here, we report that ABCG11 is involved in cytokinin-mediated development.

Transcriptomic, Hormonomic and Metabolomic Analyses Highlighted the Common Modules Related to Photosynthesis, Sugar Metabolism and Cell Division in Parthenocarpic Tomato Fruits during Early Fruit Set.

Parthenocarpy, the pollination-independent fruit set, can raise the productivity of the fruit set even under adverse factors during the reproductive phase. The application of plant hormones stimulates parthenocarpy, but artificial hormones incur extra financial and labour costs to farmers and can induce the formation of deformed fruit. This study examines the performance of parthenocarpic mutants having no transcription factors of and and that do not have the protein-coding gene, , in tomato (cv.

Cytosolic Glutamine Synthetase GS1;3 Is Involved in Rice Grain Ripening and Germination.

Ammonium is combined with glutamate to form glutamine. This reaction is catalyzed by glutamine synthetase (GS or GLN). Plants harbor several isoforms of cytosolic GS (GS1).

Regulation of ammonium acquisition and use in Oryza longistaminata ramets under nitrogen source heterogeneity.

Oryza longistaminata, a wild rice, vegetatively reproduces and forms a networked clonal colony consisting of ramets connected by rhizomes. Although water, nutrients, and other molecules can be transferred between ramets via the rhizomes, inter-ramet communication in response to spatially heterogeneous nitrogen availability is not well understood. We studied the response of ramet pairs to heterogeneous nitrogen availability using a split hydroponic system that allowed each ramet root to be exposed to different conditions.

Root-specific Reduction of Cytokinin Perception Enhances Shoot Growth in Arabidopsis thaliana.

Previous studies suggest that root-derived cytokinins (CKs) contribute to shoot growth via long-distance transport; therefore, we hypothesized that an increase in root-derived CKs enhances shoot growth. To verify this, we grafted Arabidopsis Col-0 (wild type, WT) scion onto rootstock originated from WT or a double-knockout mutant of CK receptors Arabidopsis histidine kinase 2 (AHK2) and AHK3 (ahk2-5 ahk3-7; ahk23) because this mutant overaccumulates CKs in the body probably due to feedback homeostasis regulation. The grafted plants (scion/rootstock: WT/WT and WT/ahk23) were grown in vermiculite pots or solid media for vegetative growth and biochemical analysis.