Search for: All records

Centromeres are essential for chromosome function, yet their role in shaping genome evolution in polyploid plants remains poorly understood. Allopolyploidy, where post-hybridization genome doubling merges parental genomes that may differ markedly in chromosomal architecture, has the potential to increase centromeric complexity and influence genomic plasticity. We explore this possibility in carnivorous Caryophyllales, a morphologically and chromosomally diverse plant lineage encompassing sundews, Venus flytraps, and Nepenthes pitcher plants. Focusing on sundews (Drosera), we generated chromosome-scale assemblies of holocentric D. regia and monocentric D. capensis, which share an allohexaploid origin but have diverged dramatically in genome structure. D. regia retains ancestral chromosomal fusions, dispersed centromeric repeats, and conserved synteny, whereas D. capensis exhibits extensive chromosomal reorganization and regionally localized centromeres after a lineage-specific genome duplication. Phylogenomic evidence traces D. regia to an ancient hybridization between sundew- and Venus flytrap-like ancestors, setting it apart within its infrageneric context. Genus-wide satellite DNA repeat profiling reveals rapid turnover and species-level variation in centromere organization. Together, these results establish sundews as a natural system for investigating how centromere dynamics interact with recurrent polyploidization and episodes of ecological innovation to shape genomic resilience. 

Abstract Living in nutrient-poor environments, the carnivorous Venus flytrapDionaea muscipulacaptures animal prey to compensate for this deficiency. Stimulation of trigger hairs located on the inner trap surface elicits an action potential (AP). While two consecutive APs result in fast trap closure in wildtype (WT) plants, sustained AP generation by the insect struggling to escape the trap leads to jasmonic acid (JA) biosynthesis, formation of the digestive “stomach”, and release of enzymes needed to decompose the victim. TheDionaea muscipulaDYSCALCULIA (DYSC) mutant is able to fire touch-induced APs, but unlike WT plants, it does not snap-close its traps after two consecutive APs. Moreover, DYSC plants fail to properly initiate the JA pathway in response to mechanostimulation and even wounding, a well-known JA-dependent process conserved among plants. As demonstrated in previous studies, this DYSC mutant defect is associated with impaired decoding of mechanostimulation (i.e. touch) -induced Ca²⁺signals. External JA application to the trap, however, restores slow trap closure and digestive gland function in DYSC, while rapid trap closure is JA-independent and cannot be rescued by exogenous JA application. Higher frequency mechanostimulation and thus more APs, however, revealed that DYSC is still able to close its traps, albeit much slower than WT plants. To reveal the molecular underpinnings of DYSC’s delayed trap movement, we generated a chromosome-scaleDionaeagenome assembly and profiled gene expression. The refined transcriptomic analysis uncovered widespread misregulation of cell wall-related genes in DYSC, implicating altered cell wall plasticity in the sluggish mutant. Cell indentation studies by atomic force microscopy revealed a strictly localized and strikingly enhanced stiffening of the cell wall for DYSC that may hinder rapid trap closure and snap buckling. Together, these genomic, transcriptomic, and biophysical data identify cell wall elasticity as a key constraint on voltage and Ca²⁺dependent trap kinetics. This finding documents the interrelationship between mechanosensing and Ca²⁺signaling in the ultrafast capture organ of the Venus flytrap. 

Abstract To survive in the nutrient-poor habitats, carnivorous plants capture small organisms comprising complex substances not suitable for immediate reuse. The traps of carnivorous plants, which are analogous to the digestive systems of animals, are equipped with mechanisms for the breakdown and absorption of nutrients. Such capabilities have been acquired convergently over the past tens of millions of years in multiple angiosperm lineages by modifying plant-specific organs including leaves. The epidermis of carnivorous trap leaves bears groups of specialized cells called glands, which acquire substances from their prey via digestion and absorption. The digestive glands of carnivorous plants secrete mucilage, pitcher fluids, acids, and proteins, including digestive enzymes. The same (or morphologically distinct) glands then absorb the released compounds via various membrane transport proteins or endocytosis. Thus, these glands function in a manner similar to animal cells that are physiologically important in the digestive system, such as the parietal cells of the stomach and intestinal epithelial cells. Yet, carnivorous plants are equipped with strategies that deal with or incorporate plant-specific features, such as cell walls, epidermal cuticles, and phytohormones. In this review, we provide a systematic perspective on the digestive and absorptive capacity of convergently evolved carnivorous plants, with an emphasis on the forms and functions of glands.