Genetius

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 plant spliceosomal protein AtSF1 in Arabidopsis thaliana, using iCLIP and RNA‑seq to map its in vivo branch point binding sites and demonstrate that loss of AtSF1 causes widespread 3' splice‑site mis‑selection. Structural comparison reveals a plant‑specific domain architecture, and the identified AtSF1 targets are enriched for circadian and defense genes, linking splicing regulation to timing and immunity.

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.

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 reveals that the energy sensor SnRK1 modulates Arabidopsis defense by repressing SA‑dependent gene expression and bacterial resistance, with its activity enhanced under high humidity. SnRK1 interacts with TGA transcription factors to attenuate PR1 expression, linking cellular energy status to immune regulation.

The study identified two subclades of Arabidopsis NUDIX hydrolases that selectively hydrolyze distinct inositol pyrophosphate isomers, with subclade I targeting 4-InsP7 and subclade II targeting 3-InsP7 in a Mg2+-dependent manner. Loss-of-function mutants of subclade II NUDTs displayed disrupted phosphate and iron homeostasis, elevated 1/3-InsP7 levels, and increased resistance to Pseudomonas syringae, revealing roles in nutrient signaling and plant immunity, while cross-kingdom analyses showed conserved PP-InsP‑metabolizing activities.

The study used single‑cell transcriptomics to compare Arabidopsis thaliana leaf cell responses during pattern‑triggered and effector‑triggered immunity, revealing that core defense modules are broadly shared but differ in timing, intensity, and cell‑type specific receptor dynamics. Distinct mesophyll subpopulations showed divergent resilience patterns, and gene regulatory network analysis identified WRKY‑regulated and salicylic‑acid biosynthesis modules, with the cue1-6 mutant confirming robustness of core immune responses while exposing cryptic sucrose‑responsive pathways.

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.

The study reveals that a conserved clade of pentatricopeptide repeat (PPR) genes in Arabidopsis thaliana generates secondary siRNAs that contribute to plant immunity, with these PPR loci undergoing extensive duplication and diversification to create a varied siRNA pool for pathogen defense. This PPR‑siRNA system is proposed as a novel family of defense genes with potential for engineering broad‑spectrum disease resistance.