Biology subjects

Stellmach, H.

Publications and source records attributed to Stellmach, H..

3 recordsLinked to original sources

bioRxiv2024

The plant specific cohesin subunit SYN4 contributes to 3D genome organization and activity

O_LIChromatin architecture in the cells of animals and fungi influences gene expression. The molecular factors that influence higher genome architecture in plants and their effects on gene expression remain unknown. Cohesin complexes, conserved in eukaryotes, are essential factors in genome structuring. Here, we investigated the relevance of the plant-specific somatic cohesin subunit SYN4 for chromatin organisation in Arabidopsis thaliana. C_LIO_LIPlants mutated in SYN4 were studied using HRM, Hi-C, RNA sequencing, untargeted and targeted metabolomics and physiological assays to understand the role of this plant-specific cohesin. C_LIO_LIWe show that syn4 mutants exhibit altered intra- and interchromosomal interactions, expressed as sharply reduced contacts between telomeres and chromosome arms but not between centromeres, and differences in the placement and number of topologically associated domains (TADs)-like structures. By transcriptome sequencing, we also show that syn4 mutants have altered gene expression, including numerous genes that control abiotic stress responses. C_LIO_LIThe response to drought stress in Arabidopsis is strongly influenced by the genome structure in syn4 mutants, potentially due to altered expression of CYP707A3, an ABA 8-hydroxylase. C_LI In briefThe 3D architecture of the genome extensively influences gene expression in animals and fungi. We show that the plant-specific cohesin subunit SYN4 affects intra- and interchromosomal interactions including telomere clustering, with consequences for the expression of genes of transient and induced biological pathways and the biosynthesis of bioactive compounds. Highly condensed genome structures at the CYP707A3 locus positively affects the stress response to water deprivation regulated by abscisic acid.

genetics↗

bioRxiv2020

Jasmonate biosynthesis arising from altered cell walls is prompted by turgor-driven mechanical compression and guides root hydrotropism

Despite the vital roles of jasmonoyl-isoleucine (JA-Ile) in governing plant growth and environmental acclimation, it remains unclear what intracellular processes lead to its induction. Here, we provide compelling genetic evidence that mechanical and osmotic regulation of turgor pressure represents a key factor in eliciting JA-Ile biosynthesis. After identifying cell wall mutant alleles in KORRIGAN1 (KOR1) with elevated JA-Ile in seedling roots, we found that ectopic JA-Ile resulted from cell non-autonomous signals deriving from enlarged cortex cells compressing inner tissues and stimulating JA-Ile production. Restoring cortex cell size by cell-type-specific KOR1 complementation, by isolating a genetic kor1 suppressor, and by lowering turgor pressure with hyperosmotic treatments, abolished JA-Ile signalling. Strikingly, heightened JA-Ile levels guided kor1 roots towards greater water availability, uncovering a previously unrecognized JA-Ile function in root hydrotropism. Collectively, these findings enhance our understanding of JA-Ile biosynthesis initiation, and reveal a novel role of JA-Ile in orchestrating environmental resilience.

plant biology↗

bioRxiv2019

Shoot-to-root translocation of the jasmonate precursor 12-oxo-phytodienoic acid (OPDA) coordinates plant growth responses following tissue damage

Multicellular organisms rely upon the movement of signaling molecules across cells, tissues and organs to communicate among distal sites. In plants, herbivorous insects, necrotrophic pathogens and mechanical wounding stimulate the activation of the jasmonate (JA) pathway, which in turn triggers the transcriptional changes necessary to protect plants against those challenges, often at the expense of growth. Although previous evidence indicated that JA species can translocate from damaged into distal sites, the identity of the mobile compound(s), the tissues through which they translocate and the consequences of their relocation remain unknown. Here, we demonstrated that endogenous JA species generated after shoot injury translocate to unharmed roots via the phloem vascular tissue in Arabidopsis thaliana. By wounding wild-type shoots of chimeric plants and by quantifying the relocating compounds from their JA-deficient roots, we uncovered that the JA-Ile precursor 12-oxo-phytodienoic acid (OPDA) is a mobile JA species. Our data also showed that OPDA is a primary mobile compound relocating to roots where, upon conversion to the bioactive hormone, it induces JA-mediated gene expression and root growth inhibition. Collectively, our findings reveal the existence of long-distance transport of endogenous OPDA which serves as a communication molecule to coordinate shoot-to-root responses, and highlight the importance of a controlled distribution of JA species among organs during plant stress acclimation.

plant biology↗