The study investigated meristem activation in the liverwort Marchantia polymorpha, revealing that simulated shade causes alternating inactivity of meristems. Transcriptomic comparison of active versus inactive meristems identified the cytochrome P450 monooxygenase MpCYP78E1 as an inhibitor of meristem activity and initiation, with loss- and gain-of-function mutants confirming its regulatory role in shoot branching architecture.
The study examines how the SnRK1 catalytic subunit KIN10 integrates carbon availability with root growth regulation in Arabidopsis thaliana. Loss of KIN10 reduces glucose‑induced inhibition of root elongation and triggers widespread transcriptional reprogramming of metabolic and hormonal pathways, notably affecting auxin and jasmonate signaling under sucrose supplementation. These findings highlight KIN10 as a central hub linking energy status to developmental and environmental cues in roots.
The study demonstrates that MYB‑bHLH‑WDR transcriptional complexes (MBW) are present in the liverwort Marchantia polymorpha, indicating that such complexes originated before the diversification of land plants. Functional analyses reveal that two MYB paralogs, MpMYB14 and MpMYB02, rely on a single bHLH partner (MpbHLH12) to regulate flavonoid biosynthesis and liverwort‑specific oil body maturation, suggesting an ancestral role in pigment production and a derived role in organelle development.
The authors adapted OpenPlant kit CRISPR/Cas9 tools to enable multiplex gRNA expression from a single transcript using tRNA sequences in the liverwort Marchantia polymorpha, markedly enhancing editing efficiency and scalability. They coupled this vector system with a simplified, optimized thallus transformation protocol, providing a rapid and versatile platform for generating CRISPR/Cas9 mutants and advancing functional genomics in this model species.
The study used comparative transcriptomics across Erysimum species to identify two 2‑oxoglutarate‑dependent dioxygenases, CARD5 and CARD6, responsible for the 14β‑ and 21‑hydroxylation steps in cardenolide biosynthesis in Erysimum cheiranthoides. Knockout mutants lacking these genes accumulated pathway intermediates, and transient expression in Nicotiana benthamiana confirmed their enzymatic functions, while structural modeling pinpointed residues linked to neofunctionalization.
Arsenic-sensing domain controls ACR3 transporter trafficking and function in Marchantia polymorpha
Authors: Mizio, K., Bonter, I., Zbieralski, K., Dolzblasz, A., Tomaszewska, P., Staszewski, J., Wawrzycka, D., Reymer, A., Bialek, W., Kriechbaumer, V., Haseloff, J., Wysocki, R., Maciaszczyk-Dziubinska, E.
The study characterizes MpACR3, an ACR3 transporter from the liverwort Marchantia polymorpha, demonstrating its role as a metalloid/proton antiporter that provides resistance to arsenic and moderate tolerance to antimony. The authors reveal an N‑terminal arsenic‑sensing domain that controls Golgi retention and plasma‑membrane trafficking via cysteine‑mediated conformational changes, and show that a conserved arginine motif influences both membrane accumulation and transport activity. These findings suggest a plant‑specific adaptation of ACR3 transporters to arsenic toxicity.
Comparative transcriptomics uncovers plant and fungal genetic determinants of mycorrhizal compatibility
Authors: Marques-Galvez, J. E., de Freitas Pereira, M., Nehls, U., Ruytinx, J., Barry, K., Peter, M., Martin, F., Grigoriev, I. V., Veneault-Fourrey, C., Kohler, A.
The study used comparative and de‑novo transcriptomic analyses in poplar to uncover plant and fungal gene regulons that govern ectomycorrhizal (ECM) compatibility, distinguishing general fungal‑sensing responses from ECM‑specific pathways. Key findings include modulation of jasmonic acid‑related defenses, coordinated regulation of secretory and cell‑wall remodeling genes, and dynamic expression of the Common Symbiosis Pathway during early and mature symbiosis stages.
High radiosensitivity in the conifer Norway spruce (Picea abies) due to lesscomprehensive mobilisation of protection and repair responses compared to the radiotolerant Arabidopsis thaliana
Authors: Bhattacharjee, P., Blagojevic, D., Lee, Y., Gillard, G. B., Gronvold, L., Hvidsten, T. R., Sandve, S. R., Lind, O. C., Salbu, B., Brede, D. A., Olsen, J. E.
The study compared early protective, repair, and stress responses to chronic gamma irradiation in the radiosensitive conifer Norway spruce (Picea abies) and the radiotolerant Arabidopsis thaliana. Norway spruce exhibited growth inhibition, mitochondrial damage, and higher DNA damage at low dose rates, while Arabidopsis maintained growth, showed minimal organelle damage, and activated DNA repair and antioxidant genes even at the lowest dose rates. Transcriptomic analysis revealed that the tolerant species mounts a robust transcriptional response at low doses, whereas the sensitive species only responds at much higher doses.
The study used comparative transcriptomics to examine how Fusarium oxysporum isolates with different lifestyles on angiosperms regulate effector genes during infection of the non‑vascular liverwort Marchantia polymorpha. Core effector genes on fast core chromosomes are actively expressed in the bryophyte host, while lineage‑specific effectors linked to angiosperm pathogenicity are silent, and disruption of a compatibility‑associated core effector alters the expression of other core effectors, highlighting conserved fungal gene networks across plant lineages.
Phylogenetic analysis reveals that non‑seed plants, exemplified by the liverwort Marchantia polymorpha, possess a streamlined repertoire of cyclin and CDK genes, with only three cyclins active in a phase‑specific manner during vegetative development. Single‑cell RNA‑seq and fluorescent reporter assays, combined with functional overexpression studies, demonstrate the distinct, non‑redundant roles of MpCYCD;1, MpCYCA, and MpCYCB;1 in G1 entry, S‑phase progression, and G2/M transition, respectively.