Biology subjects

Kuhlmann, M.

Publications and source records attributed to Kuhlmann, M..

8 recordsLinked to original sources

bioRxiv2026

Hypermorphic TaARF4 shapes wheat architecture by repressing SPL-mediated developmental timing

Integrating spatial morphogens with temporal developmental clocks is fundamental to optimizing plant architecture and crop yield, yet their molecular interface remains elusive. Here, we characterize Branched shoot 1 (Bsh1), a semi-dominant wheat mutant exhibiting non-canonical upper-aerial branching and aberrant spike development, caused by a T265I substitution in the DNA-binding domain of the auxin response factor TaARF4-A2. Unlike flanking mutations governing protein stability in basal land plants, this central substitution uniquely converts TaARF4-A2 into an auxin-insensitive hypermorphic repressor. The mutant protein disrupts auxin-cytokinin homeostasis and markedly enhances the native repression of SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) transcription factors, the core timers of developmental phase transitions. This spatial and temporal uncoupling unleashes upper axillary buds from dormancy, promoting aerial branching and diverting resources from reproductive development. Our findings demonstrate how a conserved spatial morphogen effector was evolutionarily rewired in polyploid wheat to dictate the temporal SPL clock, orchestrating species-specific shoot architectural innovation.

plant biology↗

bioRxiv2025

Limited Water Stress Triggers Adaptive Leaf Trait Response in Australian Commercial Rice Without Compromising Grain Yield and Quality

Water scarcity poses significant challenge for the Australian rice industry, driving the need for varieties with improved water use efficiency (WUE). This study evaluated 18 Australian elite japonica, two indica rice lines, and the West African japonica cultivar Moroberekan to assess stomatal and non-stomatal leaf traits contributing to WUE. Plants were cultivated under controlled glasshouse conditions with two water treatments: ponded (PW) and limited water (LW) maintained at 60-65% field capacity throughout the vegetative stage. Under LW, plants exhibited decreased photosynthetic efficiency, stomatal conductance, and stomatal density but increased cuticular and epicuticular wax (CEW) deposition, which helped conserve water. The rice cultivar Sherpa exhibited reduced sensitivity to regulation of gas exchange, stomatal adjustments and photosynthetic efficiency, and the greatest CEW deposition among the japonica varieties, indicating potential for improved WUE. Thousand grain weight showed no significant differences between the two water treatments. Brown rice yield and milling recovery were also unaffected. Spectral analysis of dehulled seeds suggested that LW stress increased protein content but had no effect on lipids and starch. These findings demonstrate that LW during the vegetative stage can induce water-conserving traits without compromising yield or grain quality; providing valuable insights for developing water-efficient rice varieties. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=70 SRC="FIGDIR/small/655428v1_ufig1.gif" ALT="Figure 1"> View larger version (18K): org.highwire.dtl.DTLVardef@11820bcorg.highwire.dtl.DTLVardef@10d1940org.highwire.dtl.DTLVardef@f4f3c2org.highwire.dtl.DTLVardef@1af7748_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightWater scarcity elicits a range of stomatal and non-stomatal responses in Australian commercial rice varieties without compromising yield and grain quality while enhancing water conservation.

plant biology↗

bioRxiv2023

Specialized mesenteric lymphatic capillaries by-pass the mesenteric lymph node chain to transport peritoneal antigens directly into mediastinal lymph nodes.

Lymphatic vessels (LVs) are indispensable for tissue fluid homeostasis and immune cell trafficking. The network of LVs that channel fluids from the gut into mesenteric lymph nodes (MLN) has been recognized as the sole lymphatic system in the mesentery. Here we describe an alternative, functionally autonomous set of capillary mesenteric LVs (capMLVs) that by-pass the MLNs and drain directly into mediastinal LNs. CapMLVs develop perinatally from valves of collective mesenteric lymphatic vessels (colMLVs) in response to arterial endothelial cell-derived VEGF-C. Once extended, capMLVs detach from colMLVs to form an independent elongated network comprised of LYVE1+, CCL21+ endothelial cells. Avascular areas of the mesentery juxtaposed to capMLVs contain cell islets that express ACKR4. This CCL21-scavenging atypical receptor facilitates the migration of mesenteric phagocytes into capMLVs to be channeled directly into mediastinal LNs. This allows peritoneum-derived ominous antigens to be processed separately from alimentary antigens.

developmental biology↗

bioRxiv2022

Absence of microbiome in chronic infections impairs viral control without affecting CD8 T cell function

Prolonged antigen exposure in chronic viral infections reduces the effector capacity of cytotoxic T cells - a phenomenon known as T cell exhaustion. Development of T cell exhaustion is driven by high viral titers, strong TCR stimulation, and high antigen concentrations associated with strong inflammatory signals. A largely unexplored factor has been the influence of the microbiome in these processes. Here, we report that T cell exhaustion progresses independently of the presence or absence of a microbiome in chronic lymphocytic choriomeningitis virus (LCMV) infections. Virus-specific CD8 T cells in germ-free mice showed high expression of the inhibitory receptor PD-1 and decreased cytokine production. Moreover, their global gene expression patterns, as determined by single-cell sequencing, were similar to those of cells in specific pathogen-free mice. In line with this, we observed similar pathogen loads with and without a microbiome. Thus, our study demonstrates that the microbiome is dispensable for the induction of T cell exhaustion and for the limited virus control seen in chronic LCMV infections.

immunology↗

bioRxiv2022

Parental pericentromeric methylation status drives methylome remodelling and heterosis in epigenetic hybrids

Heterosis is the superior phenotypic performance of F1 hybrids relative to their parents. Although this phenomenon is extensively exploited commercially, its molecular causes remain elusive. A central challenge is to understand how specific features of parental (epi)genomes contribute to the widespread functional remodelling that occurs in hybrids. Using Arabidopsis, we show that differentially methylated regions (DMRs) in parental pericentromeres act as major re-organizers of hybrid methylomes and transcriptomes, even in the absence of genetic variation. We demonstrate that these parental DMRs facilitate methylation changes in the hybrids not only in cis, but also in trans at thousands of target regions throughout the genome. Many of these trans-induced changes facilitate the expression of nearby genes, and are significantly associated with phenotypic heterosis. Our study establishes the epigenetic status of parental pericentromeres as an important predictor of heterosis and elucidates its pleiotropic potential in the functional remodelling of hybrid genomes.

genomics↗

bioRxiv2021

Dosage of duplicated and antifunctionalized homeobox proteins influences spikelet development in barley

Illuminating the mechanisms of inflorescence architecture of grain crops that feed our world may strengthen the goal towards sustainable agriculture. Lateral spikelet development of barley (Hordeum vulgare L.) is such an example of a floral architectural trait regulated by VRS1 (Vulgare Row-type Spike 1 or Six-rowed Spike 1, syn. HvHOX1). Its lateral spikelet-specific expression and the quantitative nature of suppressing spikelet development were previously shown in barley. However, the mechanistic function of this gene and its paralog HvHOX2 on spikelet development is still fragmentary.Here, we show that these duplicated transcription factors (TFs) have contrasting nucleotide diversity in various barley genotypes and several Hordeum species. Despite this difference, both proteins retain their basic properties of the homeodomain leucine zipper class I family of TFs. During spikelet development, these genes exhibit similar spatiotemporal expression patterns yet with anticyclic expression levels. A gene co-expression network analysis suggested that both have an ancestral relationship but their functions appear antagonistic to each other, i.e., HvHOX1 suppresses whereas HvHOX2 rather promotes spikelet development. Our transgenic promoter-swap analysis showed that HvHOX2 can restore suppressed lateral spikelets when expression levels are increased; however, at its low endogenous expression level, HvHOX2 appears dispensable for spikelet development. Collectively, this study proposes that the dosage of the two antagonistic TFs, HvHOX1 and HvHOX2, influence spikelet development in barley.

plant biology↗

bioRxiv2020

INTERMEDIUM-C mediates the shade-induced bud growth arrest in barley

Tiller formation is a key agronomic determinant for grain yield in cereal crops. The modulation of this trait is controlled by transcriptional regulators and plant hormones, tightly regulated by external environmental conditions. While endogenous (genetics) and exogenous (environmental factors) triggers for tiller formation have mostly been investigated separately, it has remained elusive how they are integrated into the developmental program of this trait. The transcription factor INTERMEDIUM-C (INT-C), which is the barley ortholog of the maize domestication gene TEOSINTE BRANCHED1 (TB1) has a prominent role in regulating tiller bud outgrowth. Here we show that INT-C is expressed in tiller buds, required for bud growth arrest in response to shade. In contrast to wild type plants, int-c mutant plants are impaired in their shade response and do not stop tiller production after shading. Gene expression levels of INT-C are up-regulated under light-limiting growth conditions, and down-regulated after decapitation. Transcriptome analysis of wild-type and int-c buds under control and shading conditions identified target genes of INT-C that belong to auxin and gibberellin biosynthesis and signaling pathways. Our study identifies INT-C as integrator of the shade response into tiller formation, which is prerequisite for implementing shading responses in the breeding of cereal crops.

plant biology↗

bioRxiv2019

Risks to pollinators from different land-use transitions: bee species’ responses to agricultural expansion show strong phylogenetic signal

Bee species worldwide are facing a future of further land-use change and intensification. Populations of closely-related species with similar ecological characteristics are likely to respond similarly to such pressures. Such phylogenetic signal in species responses could undermine the stability of pollination services in agricultural and natural systems. We use abundance data from a global compilation of bee assemblages in different land uses to assess the sensitivity of 573 bee species to agricultural expansion, intensification and urbanization; and combine the results with the Bee Tree of Life to assess phylogenetic signal. In addition, we assess whether variation in species sensitivity to land-use change is better explained by phylogenetic or available functional trait differences. Bee species show strong phylogenetic signal in sensitivity to agricultural land expansion but only a weak signal in sensitivity to agricultural intensification and urbanisation. Sensitivities were usually best explained by a combination of functional and phylogenetic distances. This finding suggests that the commonly-recorded traits, despite being meaningful as functional response traits, do not capture all important determinants of bee species vulnerability or resistance. However, it also suggests that model-based predictions of the sensitivity of poorly known species may be sufficient to help guide conservation efforts.

ecology↗