Genetius

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 reveals that the Arabidopsis O-GlcNAc transferase SEC is essential for timely ABA‑induced stomatal closure and drought tolerance, with sec-5 mutants showing delayed closure and increased water loss, while SEC overexpression enhances responsiveness. SEC influences guard‑cell microtubule remodeling, as loss of SEC impairs microtubule reorganization and SEC directly interacts with tubulin α‑4, suggesting tubulin as a target of O‑GlcNAcylation.

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 investigated the five Arabidopsis SCAMP proteins, focusing on SCAMP5, and identified conserved tyrosine and NPF motifs that mediate anterograde transport and endocytosis, respectively. SCAMPs were shown to dimerize at the plasma membrane and endosomes, interact with plasma‑membrane aquaporins, and their loss (triple and quintuple mutants) conferred mild developmental delay but increased drought tolerance, likely via altered PIP trafficking or stability.

The study examines how autophagy-related genes AtATG5 and AtATG7 influence Arabidopsis seed germination and ABA responses, revealing that atg5 and atg7 mutants germinate more slowly and display altered lipid droplet and protein storage vacuole organization. Transcriptomic and immunolocalization analyses show delayed ABI5 decay and a direct interaction between ATG8 and the autophagy machinery, implicating autophagy in seed reserve mobilization via transcription factor turnover.

Loss‑of‑function mutations in the drought‑induced genes GASA3 and AFP1 confer enhanced drought tolerance in Arabidopsis thaliana, primarily through smaller stomatal apertures and increased ABA accumulation via hydrolysis of ABA‑GE. Constitutive overexpression of these genes heightens drought sensitivity, indicating that the AFP1/GASA3 module negatively regulates stomatal closure and ABA signaling.

The study reveals that root hair cells rely on elevated autophagy to extend their lifespan, and that loss-of-function mutations in autophagy genes ATG2, ATG5, or ATG7 trigger premature, cell-autonomous death mediated by NAC transcription factors ANAC046 and ANAC087. This uncovers an antagonistic interaction between autophagy and a developmentally programmed cell death pathway that controls root hair longevity, highlighting a potential target for improving nutrient and water uptake in crops.