The study identifies the cysteine‑rich receptor‑like kinase CRK5 as a negative regulator of salicylic‑acid‑mediated cell death and a positive regulator of antioxidant homeostasis during dark‑induced leaf senescence in Arabidopsis. Loss‑of‑function crk5 mutants display accelerated senescence, elevated ROS and electrolyte leakage, and altered antioxidant enzyme activities, phenotypes that are rescued by suppressing SA biosynthesis or catabolism. Transcriptome analysis reveals extensive deregulation of senescence‑ and redox‑related genes, highlighting CRK5’s central role in coordinating hormonal and oxidative pathways.
The study characterizes the chloroplast‑localized protein AT4G33780 in Arabidopsis thaliana using CRISPR/Cas9 knockout and overexpression lines, revealing tissue‑specific expression and context‑dependent effects on seed germination, seedling growth, vegetative development, and root responses to nickel stress. Integrated transcriptomic (RNA‑seq) and untargeted metabolomic analyses show extensive transcriptional reprogramming—especially of cell‑wall genes—and altered central energy metabolism, indicating AT4G33780 coordinates metabolic state with developmental regulation rather than controlling single pathways.
Identification of a putative RBOHD-FERONIA-CRK10-PIP2;6 plasma membrane complex that interacts with phyB to regulate ROS production in Arabidopsis thaliana
Authors: Mohanty, D., Fichman, Y., Pelaez-Vico, M. A., Myers, R. J., Sealander, M., Sinha, R., Morrow, J., Eckstein, R., Olson, K., Xu, C., An, H., Yoo, C. Y., Zhu, J.-K., Zhao, C., Zandalinas, S. I., Liscum, E., Mittler, R.
The study demonstrates that FERONIA and phytochrome B physically interact with the NADPH oxidase RBOHD, and that FERONIA-mediated phosphorylation of phyB is essential for RBOHD-driven ROS production under excess light stress in Arabidopsis thaliana. Additional membrane proteins CRK10 and PIP2;6 also associate with this complex, forming a plasma‑membrane assembly that integrates multiple signaling pathways to regulate stress‑induced ROS.
The study examined how Arabidopsis calcium‑dependent protein kinases AtCPK5 and AtCPK6 modulate immunity triggered by bacterial rhamnolipids, finding that RLs up‑regulate these kinases and that mutants, especially cpk5/6, show altered reactive oxygen species production and defense gene expression. However, these kinases did not influence RL‑induced electrolyte leakage or resistance to Pseudomonas syringae pv. tomato DC3000, indicating additional signaling components are involved.
Phosphoproteomics uncovers rapid and specific transition from plant two-component system signaling to Ser/Thr phosphorylation by the intracellular redox sensor AHK5
Authors: Drechsler, T., Li, Z., Schulze, W. X., Harter, K. J. W.
A comparative phosphoproteomics study using Arabidopsis thaliana ahk5 loss‑of‑function mutants and wild‑type seedlings revealed that the histidine kinase AHK5 mediates a rapid shift from multistep phosphorelay signaling to serine/threonine phosphorylation in response to H2O2. AHK5 controls ROS‑responsive phosphorylation of plasma‑membrane nanodomain proteins and orchestrates distinct ABA‑independent stomatal closure and ABA‑dependent root development pathways by modulating key components such as RBOHD, CAS, HPCA1, and auxin transporters.
The study used CRISPR/Cas9 to edit the downstream region of the Arabidopsis thaliana FLOWERING LOCUS T (FT) gene, identifying a 2.3‑kb segment containing the Block E enhancer as crucial for normal FT expression and flowering. Fine‑scale deletions pinpointed a 63‑bp core module with CCAAT‑ and G‑boxes, and revealed a cryptic CCAAT‑box that becomes active when repositioned, highlighting the importance of local chromatin context and motif arrangement for enhancer function.
DECREASE IN DNA METHYLATION 1-mediated epigenetic regulation maintains gene expression balance required for heterosis in Arabidopsis thaliana
Authors: Matsuo, K., Wu, R., Yonechi, H., Murakami, T., Takahashi, S., Kamio, A., Akter, M. A., Kamiya, Y., Nishimura, K., Matsuura, T., Tonosaki, K., Shimizu, M., Ikeda, Y., Kobayashi, H., Seki, M., Dennis, E. S., Fujimoto, R.
The study demonstrates that the chromatin remodeler DDM1 is essential for biomass heterosis in Arabidopsis thaliana hybrids, as loss of DDM1 function leads to reduced rosette growth and extensive genotype‑specific transcriptomic and DNA methylation changes. Whole‑genome bisulfite sequencing revealed widespread hypomethylation in ddm1 mutants, while salicylic acid levels were found unrelated to heterosis, indicating that epigenetic divergence, rather than SA signaling, underpins hybrid vigor.
The study applied a progressive, sublethal drought treatment to Arabidopsis thaliana, collecting time‑resolved phenotypic and transcriptomic data. Machine‑learning analysis revealed distinct drought stages driven by multiple overlapping transcriptional programs that intersect with plant aging, and identified high‑explanatory‑power transcripts as biomarkers rather than causal agents.
A copper-dependent, redox-based hydrogen peroxide perception in plants
Authors: Ishihama, N., Fukuda, Y., Shirano, Y., Takizawa, K., Hiroyama, R., Fujimoto, K. J., Ito, H., Nishimura, M., Yanai, T., Inoue, T., Shirasu, K., Laohavisit, A.
The study resolves the ectodomain structure of the plant-specific LRR‑RLK CARD1 (HPCA1) and reveals a surface‑exposed copper ion coordinated by histidines that is essential for hydrogen peroxide signaling. Combined structural, genetic, and biochemical analyses show that previously identified cysteine residues are not required for signal perception, establishing CARD1 as the first copper‑dependent redox receptor.
Enhancement of Arabidopsis growth by Enterobacter sp. SA187 under elevated CO2 is dependent on ethylene signalling activation and primary metabolism reprogramming
Authors: Ilyas, A., Mauve, C., Pateyron, S., Paysant-Le Roux, C., Bigeard, J., Hodges, M., de Zelicourt, A.
The study shows that inoculating Arabidopsis thaliana with the plant‑growth‑promoting bacterium Enterobacter sp. SA187 markedly boosts root and shoot biomass under elevated CO₂, accompanied by altered nitrogen and carbon content and reshaped phytohormone signaling. Transcriptomic and metabolomic analyses reveal activation of salicylic acid, jasmonic acid, and ethylene pathways and enhanced primary metabolism, while the ethylene‑insensitive ein2‑1 mutant demonstrates that the growth benefits are ethylene‑dependent.