MdBRC1 and MdFT2 Interaction Fine-Tunes Bud Break Regulation in Apple
Authors: Gioppato, H. A., Estevan, J., Al Bolbol, M., Soriano, A., Garighan, J., Jeong, K., Georget, C., Soto, D. G., El Khoury, S., Falavigna, V. d. S., George, S., Perales, M., Andres, F.
The study identifies the transcription factor MdBRC1 as a key inhibitor of bud growth during the ecodormancy phase in apple (Malus domestica), directly regulating dormancy‑associated genes and interacting with the flowering promoter MdFT2 to modulate bud break. Comparative transcriptomic analysis and gain‑of‑function experiments in poplar demonstrate that MdFT2 physically binds MdBRC1, attenuating its repressive activity and acting as a molecular switch for the transition to active growth.
The study introduced full-length SOC1 genes from maize and soybean, and a partial SOC1 gene from blueberry, into tomato plants under constitutive promoters. While VcSOC1K and ZmSOC1 accelerated flowering, all three transgenes increased fruit number per plant mainly by promoting branching, and transcriptomic profiling revealed alterations in flowering, growth, and stress‑response pathways.
The study introduces a CRISPR/Cas9‑based restoration system (CiRBS) that reactivates a disabled luciferase reporter (LUC40Ins26bp) in transgenic Arabidopsis, enabling long‑term single‑cell bioluminescence monitoring. Restoration occurs within 24 h after particle‑bombardment‑mediated CRISPR delivery, with ~7 % of cells regaining luminescence and most restored cells carrying a single correctly edited chromosome, facilitating reliable analysis of cellular gene‑expression heterogeneity.
The study used CRISPR/Cas9 to create rice lines with one to three tandem copies of the OsMADS18 gene and confirmed copy-number through high‑throughput qPCR. Incremental increases in OsMADS18 copy number produced proportional rises in transcript levels and corresponding enhancements in leaf blade and culm length, showing that gene dosage can be leveraged to fine‑tune agronomic traits.
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.
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.
The study investigated how molecular factors determine the developmental fate of axillary buds (AXB) in Fragaria vesca, distinguishing between stolon formation and branch crown development. By combining phenotypic analysis of AXB development with RNA‑seq of undifferentiated buds across three genotypes, the authors identified FveBRC1 as a key regulator, and confirmed its role using CRISPR/Cas9‑generated brc1 mutants. These findings enhance understanding of AXB fate control and its impact on strawberry fruit yield.