Biology subjects

Slawinska, M. W.

Publications and source records attributed to Slawinska, M. W..

3 recordsLinked to original sources

bioRxiv2022

Differential expression analysis of sexual and apomictic Boechera uncovers FAS4 as crucial for gametogenesis

During sexual reproduction of higher plants, seed formation is initiated by double fertilization of egg and central cell. In contrast, pseudogamous apomicts form embryos asexually by parthenogenesis of the egg, but initiation of endosperm development still depends on central cell fertilization. It can be envisioned that these differences are determined during gametogenesis and specification of gametophytic cells. To deepen the understanding of the transcriptional basis underlying sexual and apomictic reproduction, we applied tissue type-specific RNA-Seq. We compared expression in reproductive tissues of different Boechera accessions at distinct developmental stages. This confirmed previous evidence for an enrichment of RNA helicases at onset of reproductive development. We further identified a small number of members of this gene family as differentially expressed in female reproductive ovule tissues harbouring mature gametophytes from apomictic and sexual accessions. This included homologues of A. thaliana FASCIATED STEM 4 (FAS4) and of ENHANCED SILENCING PHENOTYPE 3 (ESP3), which have previously been identified as potential candidates for gametogenesis and apomixis, respectively. Unlike in A. thaliana, for either of them additional homologues or copies of related genes are present in Boechera, indicating complex evolutionary histories. As the expression patterns implied potential roles of FAS4 during gametogenesis, we first studied A. thaliana lines carrying mutant alleles. Indeed, we observed defects during male and female gametogenesis and severely reduced transmission efficiencies through both parents. In conclusion, our study identifies FAS4 as crucial for plant reproduction and suggests the potential for sub-functionalization of additional homologous genes in Boechera to shape reproductive development.

plant biology↗

bioRxiv2022

A hair cell-specific peroxidase coordinates stomatal and prickle hair cell size to optimize epidermal cell functionality in grasses

The leaf epidermis is the outermost cell layer forming the interface between plants and the atmosphere that must both provide a robust barrier against (a)biotic stressors and facilitate carbon dioxide uptake and leaf transpiration 1. To achieve these opposing requirements, the plant epidermis developed a wide range of specialized cell types such as stomata and hair cells. While factors forming these individual cell types are known 2-5, it is poorly understood how their number and size is coordinated. Here, we identified a role for BdPRX76/BdPOX, a class III peroxidase, in regulating hair cell and stomatal size in the model grass Brachypodium distachyon. In bdpox mutants prickle hair cells were smaller and stomata were longer. Because stomatal density remained unchanged, the negative correlation between stomatal size and density was disrupted in bdpox and resulted in higher stomatal conductance and lower intrinsic water-use efficiency. BdPOX was exclusively expressed in hair cells suggesting that BdPOX cell-autonomously promotes hair cell size and indirectly restricts stomatal length. Cell wall autofluorescence and lignin stainings indicated a role for BdPOX in lignification or crosslinking of related phenolic compounds at the hair cell base. Ectopic expression of BdPOX in the stomatal lineage increased phenolic autofluorescence in guard cell walls and restricted stomatal elongation in bdpox. Together, we highlight a developmental interplay between hair cells and stomata that optimizes epidermal functionality. We propose that cell-type-specific changes disrupt this interplay and lead to compensatory developmental defects in other epidermal cell types.

plant biology↗

bioRxiv2021

Quantitative effects of environmental variation on stomatal anatomy and gas exchange in a grass model

Stomata are cellular pores on the leaf epidermis that allow plants to regulate carbon assimilation and water loss. Stomata integrate environmental signals to regulate pore apertures and optimize gas exchange to fluctuating conditions. Here, we quantified intraspecific plasticity of stomatal gas exchange and anatomy in response to seasonal variation in Brachypodium distachyon. Over the course of two years we (i) used infrared gas analysis to assess light response kinetics of 120 Bd21-3 wild-type individuals in an environmentally fluctuating greenhouse and (ii) microscopically determined the seasonal variability of stomatal anatomy in a subset of these plants. We observed systemic environmental effects on gas exchange measurements and remarkable intraspecific plasticity of stomatal anatomical traits. To reliably link anatomical variation to gas exchange, we adjusted anatomical gsmax calculations for grass stomatal morphology. We propose that systemic effects and variability in stomatal anatomy should be accounted for in long-term gas exchange studies.

plant biology↗