CLPC2 plays specific roles in CLP complex-mediated regulation of growth, photosynthesis, embryogenesis and response to growth-promoting microbial compounds
Authors: Leal-Lopez, J., Bahaji, A., De Diego, N., Tarkowski, P., Baroja-Fernandez, E., Munoz, F. J., Almagro, G., Perez, C. E., Bastidas-Parrado, L. A., Loperfido, D., Caporalli, E., Ezquer, I., Lopez-Serrano, L., Ferez-Gomez, A., Coca-Ruiz, V., Pulido, P., Morcillo, R. J. L., Pozueta-Romero, J.
The study demonstrates that the plastid chaperone CLPC2, but not its paralogue CLPC1, is essential for Arabidopsis responsiveness to microbial volatile compounds and for normal seed and seedling development. Loss of CLPC2 alters the chloroplast proteome, affecting proteins linked to growth, photosynthesis, and embryogenesis, while overexpression of CLPC2 mimics CLPC1 deficiency, highlighting distinct functional roles within the CLP protease complex.
SPOROCYTELESS/NOZZLE acts together with MADS-domain transcription factors to regulate an auxin-dependent network controlling the Megaspore Mother Cell development
Authors: Cavalleri, A., Astori, C., Manrique, S., Bruzzaniti, G., Smaczniak, C., Mizzotti, C., Ruiu, A., Spano, M., Movilli, A., Gregis, V., Xu, X., Kaufmann, K., Colombo, L.
The study elucidates the SPL/NZZ‑dependent regulatory pathway governing megaspore mother cell (MMC) differentiation, revealing that SPL/NZZ directly targets genes and interacts with ovule‑identity MADS‑domain transcription factor complexes. Integration of multi‑omics data with genetic complementation and mutant analyses uncovers an auxin‑dependent downstream network that drives MMC formation.
The study investigated how barley (Hordeum vulgare) adjusts mitochondrial respiration under salinity stress using physiological, biochemical, metabolomic and proteomic approaches. Salt treatment increased respiration and activated the canonical TCA cycle, while the GABA shunt remained largely inactive, contrasting with wheat responses.
The study demonstrates that very long chain sphingolipids in the outer membrane leaflet interdigitate with inner‑leaflet phosphatidylserine, forming a vertical bridge that organizes PS nanodomains and enables auxin‑induced activation of the Rho‑GTPase ROP6. Disruption of sphingolipid biosynthesis disperses these nanodomains, impairing ROP6 signaling, cytoskeletal dynamics, and directional growth, highlighting interleaflet coupling as a key mechanism linking membrane asymmetry to plant signal transduction.
The study combined high-throughput image-based phenotyping with genome-wide association studies to uncover the genetic architecture of tolerance to the spittlebug Aeneolamia varia in 339 interspecific Urochloa hybrids. Six robust QTL were identified for plant damage traits, explaining up to 21.5% of variance, and candidate genes linked to hormone signaling, oxidative stress, and cell‑wall modification were highlighted, providing markers for breeding.
The study investigates how the timing of the vegetative phase change (VPC) in Arabidopsis thaliana influences drought adaptation, revealing strong genotype-by-environment interactions that create stage-specific fitness tradeoffs. Genotypes from warmer, drier Iberian climates transition earlier, and genome-wide association mapping identifies loci linked to VPC timing and drought response, with several candidates validated using T‑DNA insertion lines.
The study demonstrates that a rapid increase in cytosolic Ca²⁺ is the primary and sufficient signal mediating auxin‑induced root growth inhibition in Arabidopsis. Using live imaging, microfluidics, and optogenetic control of Ca²⁺ influx, the authors show that blocking Ca²⁺ entry prevents growth responses, while light‑triggered Ca²⁺ influx from the apoplast or ER mimics inhibition, indicating that diverse stimuli converge on a Ca²⁺‑dependent mechanism.
The study generated deep proteome and phosphoproteome datasets from guard cell‑enriched tissue to examine how phosphorylation regulates stomatal movements. Comparative analysis revealed increased phosphorylation of endomembrane trafficking and vacuolar proteins in closed stomata, supporting a role for phospho‑regulated trafficking in stomatal dynamics.
Uncovering the Molecular Regulation of Seed Development and Germination in Endangered Legume Paubrasilia echinata Through Proteomic and Polyamine Analyses
Authors: Vettorazzi, R. G., Carrari-Santos, R., Sousa, K. R., Oliveira, T. R., Grativol, C., Olimpio, G., Venancio, T. M., Pinto, V. B., Quintanilha-Peixoto, G., Silveira, V., Santa-Catarna, C.
The study examined seed maturation and germination in the endangered legume Paubrasilia echinata using proteomic and polyamine analyses at 4, 6, and 8 weeks post-anthesis, identifying over 2,000 proteins and linking specific polyamines to developmental stages. Mature seeds (6 weeks) showed elevated proteasome components, translation machinery, LEA proteins, and heat shock proteins, while polyamine dynamics revealed putrescine dominance in early development and spermidine/spermine association with desiccation tolerance and germination. These findings uncover dynamic molecular shifts underlying seed development and provide insights for conservation and propagation.
The study uses an optogenetic ChannelRhodopsin 2 variant (XXM2.0) to generate defined cytosolic Ca²⁺ transients in Arabidopsis root cells, revealing that these Ca²⁺ signatures suppress auxin‑induced membrane depolarization, Ca²⁺ spikes, and auxin‑responsive transcription, leading to reversible inhibition of cell division and elongation. This demonstrates that optogenetically imposed Ca²⁺ signals act as dynamic regulators of auxin sensitivity in roots.