Biology subjects

Simon, R.

Publications and source records attributed to Simon, R..

At least 19 recordsLinked to original sources

bioRxiv2026

Structural and functional insights into the role of Cysteine-Rich Receptor-Like Kinase 18 (CRK18) in Arabidopsis

Plants perceive and integrate diverse environmental signals through receptor kinase (RK) networks at the plasma membrane. Within this, Cysteine-Rich Receptor-Like Kinases (CRKs) constitute a large but not well-understood subfamily characterised by extracellular domains (ECDs) enriched in cysteine residues. CRKs have been implicated in plant responses to biotic and abiotic stress, as well as in developmental processes. Additionally, several CRKs have been proposed to act as redox sensors. Here, we investigate the homodimerization mechanism of Arabidopsis CRK18 and its regulation by redox conditions. By modulating pH and redox state, we assessed the stability and binding dynamics of the CRK18 ECD and its cysteine mutants. We also tested the plasma membrane localisation of all the cysteine mutants involved in the predicted disulfide bonds, and only CRK18C227A, C228A-ECD resembled the plasma membrane localization of wild-type CRK18. We combine co-immunoprecipitation, Forster resonance energy transfer-fluorescence lifetime imaging microscopy and microscale thermophoresis to quantify CRK18 self-association in planta and in vitro. Furthermore, we place CRK18 dimerization in a broader signalling context by identifying CRK18 interaction partners and CRK18-dependent signalling outputs. Using Arabidopsis CRK18 overexpression lines, we perform (phospho)proteomic and immunoprecipitation-mass spectrometry (IP-MS) analyses to map CRK18-centred signalling networks associated with stress-related responses. The constitutive activation of the CRK18 kinase domain and its interaction with many putative (cell wall) glycan-sensing RKs, including PERK15, suggest a regulatory role for CRK18. The absence of significant changes in the proteome and phosphoproteome of CRK18 overexpression lines in the absence of any trigger, and its restricted mobility after elicitation, suggest that CRK18 requires a stimulus for activation and possibly induces membrane microdomain reorganisation. This is in line with the infection assay with the nematode Heterodera schachtii, which causes modification and targeted damage to plant cell walls during infection, revealing that CRK18 acts as negative regulator of this process.

biochemistry↗

bioRxiv2026

Combination siRNA delivery as a therapeutic strategy for ADPKD

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic kidney disease worldwide, characterized by progressive cyst growth and inflammation, yet effective targeted therapies remain limited. Here we show that TMEM16A and MCP-1, key mediators of cyst-lining epithelial expansion and inflammatory macrophage recruitment respectively, are consistently upregulated in cyst-lining collecting duct (CD) epithelia across murine, porcine, and human ADPKD models. In human ADPKD patient cells, although individual silencing of TMEM16A or MCP-1 transcripts reduced cyst growth, combined silencing produced superior therapeutic efficacy, establishing the rationale for evaluating dual-target delivery. To achieve dual gene silencing in the kidneys, we delivered Tmem16a and Mcp-1 siRNA using peptide amphiphile micelles (PAMs), an ultrasmall nanoparticle platform that enables efficient renal targeting. To redirect siRNA-loaded PAMs to CD epithelia, we functionalized their surface with a CD-targeting peptide (CDM), which enabled preferential accumulation in cyst-lining CD epithelia. In an inducible Pkd1-deficient mouse model, co-delivery of CDMs loaded with Tmem16a and Mcp-1 siRNA reduced kidney enlargement, cystic burden, tubular injury, and macrophage infiltration, with efficacy exceeding non-targeted siRNA delivery at equivalent doses. CDM demonstrated enhanced uptake in primary human ADPKD patient-derived CD cells and dual gene silencing reduced target gene expression and cyst expansion, establishing translational relevance. These findings establish CD peptide-functionalized micelles as a route to cell-type-selective RNAi in the kidney, delivering siRNA to cyst-lining CD cells. Furthermore, because both targets, TMEM16A and MCP-1, are transcribed within CD cells, our siRNA-loaded CD-targeting micelles silence two drivers of cyst expansion, and their simultaneous suppression represents an effective therapeutic strategy for ADPKD.

bioengineering↗

bioRxiv2026

Structural Mapping of the EIN2-EIN3 Interaction Core and Its Integration with ENAP1 in Ethylene Signaling

Ethylene regulates diverse developmental processes, yet the molecular function of its central regulator, ETHYLENE INSENSITIVE 2 (EIN2), has remained unclear. Although EIN2 nuclear import is mediated by the Importin-/{beta} pathway, the molecular events initiated by EIN2 after nuclear entry were unknown. Here we show that EIN2 directly engages the transcription factor EIN3, establishing a mechanistic link between EIN2 nuclear accumulation and transcriptional activity. Microscale thermophoresis, yeast two-hybrid analysis and in planta FLIM-FRET consistently support this interaction. Domain mapping identifies EIN3 residues 86-173 as the core EIN2-binding region, and structural modeling refines the interface to a conserved segment within residues 86-120 that contacts a conserved region near the N-terminus of the EIN2-CEND fragment. In planta, EIN2 residues 1042-1214 are sufficient for EIN3 binding, revealing multiple interaction-competent surfaces with distinct affinities. The chromatin-associated protein ENAP1 also binds EIN2 and competes with EIN3, indicating a dynamic, concentration-dependent regulatory mechanism rather than a stable ternary complex. These findings define the molecular basis of the EIN2-EIN3 interaction and provide a mechanistic framework for EIN2-dependent transcriptional control in ethylene signaling.

plant biology↗

bioRxiv2026

A single-cell transcriptome atlas of the barley root apical meristem uncovers conserved and divergent roles of HvWOX5

Single-cell approaches have transformed plant developmental biology; however, cell-type-resolved resources for cereals remain limited. Here, we present a single-cell transcriptome atlas of the barley root apical meristem (RAM), which resolves 24 transcriptionally distinct cell populations. We assigned major root cell identities by integrating marker gene validation using Hybridization Chain Reaction (HCR) RNA fluorescence in situ hybridization and spatial transcriptomics with cross-species comparisons of published root atlases. Pseudotime analysis reconstructed developmental trajectories from the quiescent center to differentiating tissues, supporting the spatial and developmental organization of the atlas. We further demonstrated the utility of this resource by identifying HvWOX5 expression in the quiescent center and metaxylem and showing that HvWOX5 loss-of-function mutants displayed reduced root and meristem lengths, altered stem cell niche homeostasis, and disrupted metaxylem organization. Taken together, this atlas provides a framework for dissecting barley root development and identifies HvWOX5 as a key regulator of RAM organization and metaxylem patterning.

Plant Biology↗

bioRxiv2026

Collecting Duct-Targeted Lipid Nanoparticles Deliver Pkd2 mRNA to Restore Polycystin-2 and Attenuate ADPKD

Autosomal dominant polycystic kidney disease (ADPKD), a leading genetic cause of kidney failure, is caused by mutations in the PKD1 or PKD2 genes, resulting in functional polycystin 1 (PC1) or polycystin 2 (PC2) deficiency, and is characterized by progressive cyst expansion in the kidneys. However, no approved therapy directly restores polycystin expression, and current treatments target downstream pathways rather than the genetic defect. Gene replacement therapy offers a direct route to functional rescue, but efficient delivery to cyst-lining renal epithelia remains a major barrier. To meet this challenge, we developed a lipid nanoparticle (LNP) that incorporates a collecting duct (CD) targeting peptide (CD LNPs) to enable delivery of Pkd2 mRNA (CD-mPkd2) to renal CD epithelia, the predominant site of cyst origin. CD LNPs increased renal accumulation and targeted CD cells in vivo, outperforming non-targeted formulations. In a Pkd2-deficient mouse model, repeated administration of CD-mPkd2 induced reversal of established cystic disease, restored renal architecture, and reduced the fibrotic and inflammatory microenvironment characteristic of ADPKD. Furthermore, CD-mPkd2 was well tolerated without detectable off-target toxicity. Given that PC2 supplementation can attenuate disease in Pkd1-deficient models, we further demonstrate that a single dose of CD-mPkd2 reduces cyst burden and improves renal function across this distinct genetic background. These findings establish CD-mPkd2 as a potential therapeutic strategy for ADPKD across genetic backgrounds.

bioengineering↗

bioRxiv2026

Redox-dependent extracellular interaction networks of Cysteine-Rich Receptor-Like Kinases

Reactive oxygen species (ROS) regulate plant development and immunity, but how extracellular ROS signals are decoded and whether the Cysteine-rich Receptor-like Kinases (CRKs) truly serve as the long-suspected ROS sensors remains uncertain. Here, we combine high-throughput interactomics, redox proteomics, structural modelling, and genetics to map a ROS-dependent CRK interaction landscape in Arabidopsis thaliana. Using a redox-dependent interactome assay (RIACRK) on 40 CRK extracellular domains (ECDs), we identified ROS-modulated dimerisation networks with enhanced inter-community connectivity and hub redistribution in the presence of ROS. Integrating this with developmental and flg22-induced expression profiles reveals spatiotemporally limited subnetworks that likely function during activated immunity and leaf senescence, both of which are associated with extensive ROS production. Differential cysteine alkylation coupled with mass spectrometry shows that cysteines in a subset of CRK ectodomains undergo ROS-dependent oxidation. Notably, solvent-exposed, vicinal cysteines C228/C229 in CRK28 emerge as prime redox-sensitive candidates. CRK28 homodimerises and heterodimerises with CRK17 in vivo, and mutation of C228/C229 retains plasma membrane localisation but abolishes CRK28 homodimerisation, indicating a redox-controlled dimerisation switch. Loss of CRK28 delays senescence, while CRK28 overaccumulation from its native promoter causes dwarfism, premature senescence, autoimmune-like phenotypes, extensive phosphoproteome rewiring, and associations with Pathogenesis Related (PR) proteins, ROS-detoxifying enzymes, receptor(-like) kinases, and vesicle trafficking components. These results indicate that CRK28 is a potential ROS-regulated hub connecting extracellular redox signals to CRK network organisation, immune response, and age-related senescence.

plant biology↗

bioRxiv2026

Improving the immunogenicity of E. coli FimH via multivalent display on I53-50 nanoparticles

Urinary tract infections, caused primarily by uropathogenic E. coli, are a significant public health burden, affecting approximately 50% of women worldwide. The adhesin FimH is responsible for host receptor binding and is therefore a promising vaccine candidate, but prior studies showed that recombinant monomeric FimH is poorly immunogenic. Here we displayed FimH antigens on the two-component protein nanoparticle I53-50 to generate nanoparticle immunogens that elicit robust levels of receptor-blocking antibodies in mice and non-human primates. We produced nanoparticle immunogens displaying either the FimH lectin domain or a recently reported conformationally stabilized antigen, FimH-DSG, comprising both the lectin and pilin domains. When formulated on aluminum hydroxide, both nanoparticle immunogens elicited similar levels of receptor-blocking activity as a ten-fold higher dose of monomeric FimH-DSG formulated with a potent adjuvant. The improved manufacturability of the stabilized antigen, combined with the ability of nanoparticle display to obviate the need for complex adjuvants, provides important preclinical data for FimH-based vaccines intended to prevent urinary tract infections. More broadly, our data extend the applicability of the I53-50 nanoparticle platform, which to date has been mainly used for displaying viral and protozoan antigens, to bacterial indications.

immunology↗

bioRxiv2025

FLOWERING LOCUS T1 is a pleiotropic regulator of reproductive development, plant longevity, and source-sink relations in barley

Source-sink interactions play a critical but mechanistically underexplored role in coordinating reproductive output and longevity in plants. Here, we investigated the role of FT1, the barley homolog of the florigen FLOWERING LOCUS T (FT), in regulating source (leaf) and sink (inflorescence) development and metabolism. Using ft1 knock-out mutants in the spring barley cultivar Golden Promise, which carries a mutated ppd-H1 allele, and in an introgression line with a wild-type Ppd-H1 allele, we show that Ppd-H1 primarily regulates the timing of inflorescence development and flowering through FT1, whereas variation in tiller number and leaf size is determined by the genetic background. ft1 mutants exhibited reduced determinacy of both leaf and inflorescence meristems, resulting in increased leaf and spikelet numbers and size, but severely reduced inflorescence fertility, altered senescence patterns, and significantly extended plant longevity. The ft1 mutants exhibited a strong transcriptional reprogramming of genes involved in both the light and dark reactions of photosynthesis in the leaf, alongside an upregulation of genes associated with carbon catabolism and stress responses in the leaf and inflorescence. Elevated soluble sugar and starch levels in ft1 inflorescences indicated that the impaired development and fertility of ft1 inflorescences were not caused by carbon limitation, but instead reflected a reduced sink strength. Our work reveals that FT1 coordinates the development of vegetative and reproductive meristems and organs with plant physiology and metabolism, thereby regulating source-sink relationships and balancing plant longevity with reproductive output.

plant biology↗

bioRxiv2025

The developing leaf of the wild grass Brachypodium distachyon at single-cell resolution

Leaves are the plants main photosynthetic organs and drive Earths primary production. Grasses form longitudinal leaves with parallel venation and graminoid stomata. Yet, how distinct leaf tissues coordinatively develop to build functional grass leaf anatomy is not well understood. Here, we decoded the developing grass leaf from vegetative meristems to mature tissues using single-cell RNA-sequencing in the wild grass Brachypodium distachyon. In-depth analysis of epidermal clusters and multiplexed whole-mount RNA-fluorescence in situ hybridization resolved most epidermal lineages and confirmed them in planta. Gene regulatory network analysis distinguished the targetome of the two co-expressed, yet functionally divergent stomatal transcription factors BdMUTE and BdFAMA. Finally, we used our dataset to identify and functionally describe BdGRAS32s role in cell division inhibition and a stomata-specific function for a cell wall modifying enzyme. Together, our single-cell grass leaf atlas enables the dissection of developmental processes that shape the leaf sustaining global food production.

plant biology↗

bioRxiv2025

In situ architecture of plasmodesmata suggests mechanisms controlling intercellular exchange

Plasmodesmata are nanoscopic channels that traverse plant cell walls, establishing membrane and cytoplasmic continuity between adjacent cells to enable direct intercellular exchange. Although numerous components have been identified, their molecular organization and roles in controlling passage remain unclear. Here, we used cryo-electron tomography to resolve the in situ architecture of plasmodesmata in Physcomitrium patens across tissues and physiological states. We show how callose deposition at the cell wall shapes channel architecture to modulate permeability and identify helical protein assemblies formed by Multiple C2 domain and Transmembrane Proteins (MCTPs), which scaffold a central endoplasmic reticulum tubule and tether it to the plasma membrane. These findings define core architectural features of plasmodesmata and establish a structural framework for understanding how membrane, protein and cell wall components coordinate intercellular connectivity in plants.

cell biology↗

bioRxiv2025

Multi-omics analysis highlights the link of aging-related cognitive decline with systemic inflammation and alterations of tissue-maintenance

Aging-related cognitive decline is associated with changes across different tissues and the gut microbiome, including dysfunction of the gut-brain axis. However, only few studies have linked multi-organ alterations to cognitive decline during aging. Here we report a multi-omics analysis integrating metabolomics, transcriptomics, DNA methylation, and metagenomics data from hippocampus, liver, colon, and fecal samples of mice, correlated with cognitive performance in the Barnes Maze spatial learning task across different age groups. We identified 734 molecular features associated with cognitive rank within individual data layers, of which 227 features remain when integrating all data layers with each other. Among the single-layer predictors, several host and microbial features were highlighted, with host-associated markers being predominant. Host features associated with cognitive function mainly belong to innate and adaptive inflammatory activity (inflammaging) and developmental processes. Our findings suggest that cognitive decline in aging is tightly coupled to systemic, age-associated inflammation, potentially initiated by microbiome-driven gastrointestinal inflammatory activity, emphasizing a link between peripheral tissue alterations and brain function.

systems biology↗

bioRxiv2025

Integration of auxin and cytokinin signalling in Arabidopsis root meristem maintenance through the secreted peptide CLE40

Plant meristems perpetually generate new cells for the initiation, growth and differentiation of various cell types and organs. CLAVATA3/EMBRYO SURROUNDING REGION-RELATED (CLE) genes encode plant specific peptides exerting indispensable functions in a multitude of these developmental processes. Previously, we have described a CLE40 signaling module that regulates stemness in the distal root meristem (DRM). Here, we show that CLE40 is additionally needed to maintain the proximal root meristem (PRM). We demonstrate that in cle40 mutants, meristematic cells differentiate prematurely, resulting in shortened PRMs and ultimately, reduced root growth. Furthermore, we link these effects to increased cytokinin signaling that can be circumvented by preventing the perception of cytokinin. We highlight how increased cytokinin signaling leads to a change in auxin distribution mediated by SHORT HYPOCOTYL 2 (SHY2), which is ectopically activated if CLE40 is not active. Finally, we propose that the receptor BARELY ANY MERISTEM 1 (BAM1), but not its homolog BAM2, perceives CLE40 in the PRM.

developmental biology↗

bioRxiv2025

Imputation integrates single-cell and spatial gene expression data to resolve transcriptional networks in barley shoot meristem development

Grass inflorescences are composite structures, featuring complex sets of meristems as stem cell niches that are initiated in a repetitive manner. Meristems differ in identity and longevity, generate branches or split to form flower meristems that finally produce seeds. Within meristems, distinct cell types are determined by positional information and the regional activity of gene regulatory networks. Understanding these local microenvironments requires precise spatio-temporal information on gene expression profiles, which current technology cannot achieve. Here we investigate transcriptional changes during barley development, from the specification of meristem and organ founder cells to the initiation of distinct floral organs, based on an imputation approach integrating deep single-cell RNA sequencing with spatial gene expression data. The expression profiles of more than 40.000 genes can be analysed at cellular resolution in multiple barley tissues using the web-based graphical interface BARVISTA, which enables precise virtual microdissection to analyse any sub-ensemble of cells. Our study pinpoints previously inaccessible key transcriptional events in founder cells during primordia initiation and specification, characterises complex branching mutant phenotypes by barcoding gene expression profiles, and defines spatio-temporal trajectories during flower development. We thus uncover the genetic basis of complex developmental processes, providing novel opportunities for precisely targeted manipulation of barley traits.

plant biology↗

bioRxiv2025

The transcription factor NO TRANSMITTING TRACT / WIP2 regulates cytokinin homeostasis in Arabidopsis

NO TRANSMITTING TRACT / WIP2 (NTT/WIP2) is a zinc finger transcription factor that alters developmental programs in Arabidopsis when overexpressed. Loss of NTT function, alone or in combination with closely related genes, leads to developmental defects in gynoecia and roots, respectively. Its overexpression phenotype resembles the effects of cytokinin treatments, suggesting a potential connection to this hormonal pathway. To further investigate this connection, we conducted cytokinin content and response evaluations, and transcriptome analyses in an inducible NTT line. Alterations in cytokinin content and response, as evaluated with the TCSn::GFP line, were observed. In both cases, as in the global expression analyses, the observed changes were dependent on the tissue analyzed. Moreover, Y1H and transactivation assays suggested direct NTT binding to the IPT5, AHP6 and CKX7, regulatory regions. We propose that NTT, among other mechanisms, regulates development through the modulation of cytokinin homeostasis at different levels, including its local concentration. Since NTT is a target of AUXIN RESPONSE FACTOR 5 / MONOPTEROS, the results presented here indicate that NTT connects an auxin input to a change in cytokinin levels.

plant biology↗

bioRxiv2025

Esr1-Dependent Signaling and Transcriptional Maturation in the Medial Preoptic Area of the Hypothalamus Shapes the Development of Mating Behavior during Adolescence

Mating and other behaviors emerge during adolescence through the coordinated actions of steroid hormone signaling throughout the nervous system and periphery. In this study, we investigated the transcriptional dynamics of the medial preoptic area (MPOA), a critical region for reproductive behavior, using single-cell RNA sequencing (scRNAseq) and in situ hybridization techniques in male and female mice throughout adolescence development. Our findings reveal that estrogen receptor 1 (Esr1) plays a pivotal role in the transcriptional maturation of GABAergic neurons within the MPOA during adolescence. Deletion of the estrogen receptor gene, Esr1, in GABAergic neurons (Vgat+) disrupted the developmental progression of mating behaviors in both sexes, while its deletion in glutamatergic neurons (Vglut2+) had no observable effect. In males and females, these neurons displayed distinct transcriptional trajectories, with hormone-dependent gene expression patterns emerging throughout adolescence and regulated by Esr1. Esr1 deletion in MPOA GABAergic neurons, prior to adolescence, arrested adolescent transcriptional progression of these cells and uncovered sex-specific gene-regulatory networks associated with Esr1 signaling. Our results underscore the critical role of Esr1 in orchestrating sex-specific transcriptional dynamics during adolescence, revealing gene regulatory networks implicated in the development of hypothalamic controlled reproductive behaviors. One Sentence SummarySingle cell RNA sequencing reveals how adolescent sex hormones sculpt hypothalamic cell types required for mating behavior.

neuroscience↗

bioRxiv2025

Making plant tissue accessible for cryo-electron tomography

Cryo-Electron Tomography (cryo-ET) allows to visualize the molecular architecture of pristinely preserved cells and tissues. The workflow of sample preparation for cryo-ET is rather complex; it involves vitrification by rapid freezing followed by cryo-Focused Ion Beam (FIB) milling rendering the volumes of interest thin enough for cryo-ET data acquisition. The established protocols for single cells grown on or deposited on EM-grids are not suitable for multicellular plant tissues. Plunge-freezing does not yield vitrified samples in most cases and must be replaced by high-pressure freezing. This, in turn, necessitates extensive modifications of the subsequent FIB milling procedures. In this communication we describe procedures for sample screening, targeted FIB milling guided by cryo-fluorescence microscopy and a novel lamella trimming step that allows to obtain homogenously thin lamellae suitable for cryo-ET. We have tested all the steps along the workflow with a variety of plant tissues including the moss Physcomitrium patens and tissues of Arabidopsis thaliana and Limonium bicolor. We could demonstrate that the workflow optimized for plant tissues allows to attain subnanometer resolution in cases where subtomogram averaging is applicable.

plant biology↗

bioRxiv2024

Ocular Disease Prevalence in California Sea Lions In Human Care: Freshwater Versus Saltwater Housing

California sea lions (Zalophus californianus), are susceptible to various ocular diseases, with some literature suggesting a heightened risk for those kept in freshwater pools as opposed to saltwater. Given the potential implications of housing conditions on animal health, we wanted to analyze the ocular health of two distinct groups of sea lions kept at Nuremberg Zoo, one housed in freshwater and the other in saltwater. Data extracted from the animals medical records over a ten-year period were used to compare the incidence of eye conditions and other medical conditions observed. The results revealed no significant difference in the overall prevalence of eye diseases between the two environments. However, a distinct seasonal pattern was noted: sea lions kept in freshwater exhibited a peak in eye disorders during the summer months, while those in saltwater displayed a more uniform distribution of the occurrence of ocular diseases throughout the year. These findings suggest that sun exposure and water quality are potentially more influential factors in the development of ocular diseases in pinnipeds than salinity or UV radiation. Further studies are necessary to elucidate the underlying mechanisms and optimize care practices for these marine mammals. Simple SummaryThis study investigated the ocular health of California sea lions (Zalophus californianus) at Nuremberg Zoo, comparing those housed in freshwater pools to those in saltwater. An analysis of medical records over ten years showed no significant difference in the overall prevalence of eye diseases between the two groups. However, sea lions in freshwater experienced a peak of eye disorders in the summer, while those in saltwater had a more consistent occurrence throughout the year. These results imply that factors such as sun exposure and water quality may play a more crucial in ocular disease development than salinity or UV radiation. The study highlights the need for further research to understand these dynamics and improve care for marine mammals.

zoology↗

bioRxiv2024

From Flowering Time to High Temperature Resilience: PHOTOPERIOD 1 (PPD-H1) Controls Spike Fertility through Improving Stress Resistance and Energy Metabolism under High Ambient Temperatures

High ambient temperature (HT) impairs reproductive development and grain yield in temperate crops. To ensure reproductive success under HT, plants must maintain developmental stability. However, the mechanisms integrating plant development and temperature resilience are largely unknown. Here, we demonstrate that PHOTOPERIOD 1 (PPD-H1), homologous to PSEUDO RESPONSE REGULATOR genes of the Arabidopsis circadian clock, controls developmental stability in response to HT in barley. We analyzed HT responses in independent introgression lines with either the ancestral wild-type Ppd-H1 allele or the natural ppd-h1 variant, selected in spring varieties to delay flowering and enhance yield under favourable conditions. HT delayed inflorescence development and reduced grain number in ppd-h1 mutant lines, while the wild-type Ppd-H1 genotypes accelerated reproductive development and showed a stable grain set under HT. Using a CRISPR/Cas9-induced ppd-h1 mutant, we confirmed that the CCT domain of Ppd-H1 controls developmental stability, but not clock gene expression. Transcriptome and phytohormone analyses in developing leaves and inflorescences revealed increased stress gene expression and abscisic acid levels in the leaf and inflorescence of the natural and induced mutant ppd-h1 lines. Furthermore, the mutant ppd-h1 lines downregulated photosynthesis-and energy metabolism-related genes, and reduced auxin and cytokinin levels in the inflorescence, which impaired anther and pollen development. By contrast, in the wild-type Ppd-H1 plants, the transcriptome and phytohormone levels and anther and pollen development remained stable under HT. Our findings suggest that Ppd-H1 enhances stress resistance and energy metabolism, thereby stabilizing reproductive development, floret fertility and grain set under HT.

plant biology↗