Biology subjects

Swiezewski, S.

Publications and source records attributed to Swiezewski, S..

5 recordsLinked to original sources

bioRxiv2025

SnRK2.4 and SnRK2.10 redundantly control developmental leaf senescence by sustaining ABA production and signaling

Plants constantly and precisely control their growth by inducing distinct developmental programs to survive and produce high-quality offspring in the changing environment. The fine-tuning of the development according to endogenous and environmental signals requires exact intercellular signaling and a balanced response. Kinases of the Sucrose non-fermenting-1-Related protein Kinases type 2 (SnRK2s) family primarily take part in the response and adaptation to environmental stress factors. Notably, here we show that two ABA-non-activated SnRK2s, SnRK2.4 and SnRK2.10, are also activated in non-stress conditions in developmentally senescing leaves of Arabidopsis thaliana. Phenotypic, biochemical, and molecular analyses performed on single snrk2.4 or snrk2.10, and double snrk2.4/2.10 kinase mutants showed that SnRK2.4 and SnRK2.10, acting redundantly, promote developmental leaf senescence. Further, SnRK2.4 and SnRK2.10 enhance ABA accumulation in senescing leaves by inducing NCED2, one of key ABA biosynthesis-related genes. The two kinases induce developmental leaf senescence by modulating the expression of multiple ABA-responsive, osmotic stress, and senescence-related genes, such as the senescence master regulators ORE1, ORS1, WRKY33, WRKY75, and ANAC087. Furthermore, we show that SnRK2.4 and SnRK2.10 act upstream of MAPK signaling by enhancing the expression and activity of MAPKKK18, a senescence-inducing kinase. These results document a new regulatory function of SnRK2.4 and SnRK2.10: they are activated in Arabidopsis leaves in response to endogenous signals and redundantly induce developmental leaf senescence by stimulating ABA production and sustaining major ABA-dependent and -independent signaling pathways.

plant biology↗

bioRxiv2025

Chromatin retained MUSHER lncRNA integrates ABA and DOG1 signalling pathways to enhance Arabidopsis seeds dormancy.

Many plant lncRNAs regulate gene expression by binding to chromatin, but how they are retained at the target loci is unclear. We identify a new, chromatin-localized lncRNA - MUSHER, which activates two parallel regulatory pathways to increase Arabidopsis seed dormancy. MUSHER is upregulated in response to high temperatures, contributing to the induction of secondary dormancy. It promotes DOG1 expression by recruitment of the CPSF complex to enhance the proximal cleavage and polyadenylation at the DOG1 gene. It also increases ABA sensitivity in seeds by activating PIR1 gene transcription. These genes, located on different chromosomes, are both bound by MUSHER, despite lacking sequence homology. The chromatin association of MUSHER enables the integration of the DOG1-and ABA pathways to adjust seed germination timing. Additionally, MUSHER and other lncRNAs interact with U1 snRNP, which is required for their chromatin localisation, revealing a novel function of U1 snRNP in plants.

molecular biology↗

bioRxiv2024

The TUTase URT1 regulates the transcriptome of seeds and their primary dormancy

RNA uridylation is a pervasive mechanism that regulates the degradation of eukaryotic mRNAs. In Arabidopsis, uridylation influences mRNA decay both by favoring 5 to 3 degradation and by preventing excessive deadenylation. Yet, the significance of mRNA uridylation during plant development remains largely unknown. Here, we adapted FLEP-seq2, a method based on nanopore sequencing, to generate a comprehensive inventory of mRNA uridylation events in different Arabidopsis tissues. We also evaluated the respective contribution of the two known Arabidopsis uridylyltransferases, URT1 and HESO1, in mRNA uridylation. Our transcriptome-wide analysis showed that, URT1 is the main enzyme responsible for mRNA uridylation, in all analyzed tissues, while HESO1 can marginally uridylate mRNAs. Importantly, our results revealed the singularity of mRNA uridylation pattern in seeds and the dual function of URT1-dependent uridylation in shaping the transcriptome during seed maturation. We propose that during the late stages of seed maturation, URT1-dependent uridylation facilitates the degradation of unnecessary mRNAs encoding translation-related proteins, while also promoting the accumulation of mRNAs associated with the maturation program, by hindering their deadenylation. In line with its important function in shaping the seed transcriptome, our study also identifies URT1 as a novel regulator of seed dormancy. Overall, our study reveals the biological relevance of mRNA uridylation during the late stages of seed maturation.

plant biology↗

bioRxiv2024

Sucrose-responsive osmoregulation of plant cell size by a long non-coding RNA

The shoot of green plants is the primary site of carbon assimilation into sugars, the key source of energy and metabolic building blocks. The systemic transport of sugars is essential for plant growth and morphogenesis. Plants evolved intricate networks of molecular players to effectively orchestrate the subcellular partitioning of sugars. Dynamic distribution of these osmotically active compounds is a handy tool to regulate cell turgor pressure. Pressure-induced mechanical forces play an instructive role in developmental biology across kingdoms. Here, we functionally characterized a long non-coding RNA, CARMA, as a negative regulator of a receptor-like kinase, CANAR. Sugar-responsive CARMA specifically fine-tunes CANAR expression in the phloem, the route of sugar transport. By controlling sugar distribution, the CARMA-CANAR module allows cells to flexibly adapt to the external osmolality and adjust the size of vascular cell types during organ growth and development. We identify a nexus of plant vascular tissue formation with cell internal pressure monitoring and reveal a novel functional aspect of long non-coding RNAs in developmental biology.

plant biology↗

bioRxiv2022

The UBP5 histone H2A deubiquitinase counteracts PRC2-mediated repression to regulate Arabidopsis development and stress responses

Polycomb Repressive Complexes (PRCs) control gene expression through the incorporation of H2Aub and H3K27me3. However, there is limited knowledge about PRCs interacting proteins and their interplay with PRCs in epigenome reshaping, which is fundamental to understand gene regulatory mechanisms. Here, we identified UBIQUITIN SPECIFIC PROTEASE 5 (UBP5) as a novel interactor of the PRC2 subunit SWINGER and its associated factor PWO1 in Arabidopsis thaliana. As inferred from the functional analyses of ubp5 CRISPR-Cas9 mutant plants, UBP5 regulates plant development and stress responses, notably by promoting H2A monoubiquitination erasure, leading to transcriptional de-repression. Preferential association of UBP5 at PRC2 recruiting motifs and local H3K27me3 gaining in ubp5 mutant plants further suggest the existence of functional interplays between UBP5 and PRC2 in regulating epigenome dynamics. In summary, UBP5 provides novel insights to disentangle the complex PRC2 interaction network and is a crucial regulator of the pivotal epigenetic repressive marks H2Aub and H3K27me3.

developmental biology↗