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.

Thermopriming enhances heat stress tolerance by orchestrating protein maintenance pathways: it activates the heat shock response (HSR) via HSFA1 and the unfolded protein response (UPR) while modulating autophagy to clear damaged proteins. Unprimed seedlings cannot mount these responses, leading to proteostasis collapse, protein aggregation, and death, highlighting the primacy of HSR and protein maintenance over clearance mechanisms.

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 identifies an autophagy pathway that degrades plasma membrane-derived clathrin-coated vesicles (CCVs) during hyperosmotic stress, helping maintain membrane tension as cell volume decreases. Using live imaging and correlative microscopy, the authors show that the TPLATE complex subunits AtEH1/Pan1 and AtEH2/Pan1 act as selective autophagy receptors by directly binding ATG8, thereby removing excess membrane under drought or salt conditions.

The study investigates autophagy’s protective role against cadmium stress in Arabidopsis thaliana by comparing wild-type, atg5 and atg7 autophagy-deficient mutants, and ATG5/ATG7 overexpression lines. Cadmium exposure triggered autophagy, shown by ATG8a-PE accumulation, GFP-ATG8a fluorescence and ATG gene up-regulation, with atg5 mutants displaying heightened Cd sensitivity and disrupted metal ion homeostasis, whereas overexpression had limited impact. Genotype-specific differences between Col-0 and Ws backgrounds were also observed.

The study introduces a native‑condition method combining cell fractionation and immuno‑isolation to purify autophagic compartments from Arabidopsis, followed by proteomic and lipidomic characterisation of the isolated phagophore membranes. Proteomic profiling identified candidate proteins linked to autophagy, membrane remodeling, vesicular trafficking and lipid metabolism, while lipidomics revealed a predominance of glycerophospholipids, especially phosphatidylcholine and phosphatidylglycerol, defining the unique composition of plant phagophores.

The study identifies the Arabidopsis phospholipases LCAT3 and LCAT4 as essential components that hydrolyze membranes of autophagic bodies within the vacuole, a critical step for autophagy completion. Double mutants lacking both enzymes accumulate autophagic bodies and display diminished autophagic activity, while in vivo reconstitution shows LCAT3 initiates membrane hydrolysis, facilitating LCAT4’s function.

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.