A dual component system instructs membrane hydrolysis during the final stages of plant autophagy
Authors: Castets, J., Buridan, M., Toboso Moreno, I., Sanchez de Medina Hernandez, V., Gomez, R. E., Dittrich-Domergue, F., Lupette, J., Chambaud, C., Pascal, S., Ibrahim, T., Bozkurt, T. O., Dagdas, Y., Domergue, F., Joubes, J., Minina, A. E. A., Bernard, A.
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.
ATG8i Autophagy activation is mediated by cytosolic Ca2+ under osmotic stress in Arabidopsis thaliana
Authors: Castillo-Olamendi, L., Gutierrez-Martinez, J., Jimenez-Nopala, G., Galindo, A., Barrera-Ortiz, S., Rosas-Santiago, P., Cordoba, E., Leon, P., Porta, H.
The study examined how osmotic stress and cytosolic Ca²⁺ signaling regulate autophagy in plants by monitoring the dynamics of RFP‑tagged ATG8i. Both stimuli altered the accumulation of RFP‑ATG8i‑labeled autophagosomes in an organ‑specific way, and colocalization with the ER marker HDEL indicated that ATG8i participates in ER‑phagy during stress.
Tomato leaf transcriptomic changes promoted by long-term water scarcity stress can be largely prevented by a fungal-based biostimulant
Authors: Lopez-Serrano, L., Ferez-Gomez, A., Romero-Aranda, R., Jaime Fernandez, E., Leal Lopez, J., Fernandez Baroja, E., Almagro, G., Dolezal, K., Novak, O., Diaz, L., Bautista, R., Leon Morcillo, R. J., Pozueta Romero, J.
Foliar application of Trichoderma harzianum cell‑free culture filtrates (CF) increased fruit yield, root growth, and photosynthesis in a commercial tomato cultivar under prolonged water deficit in a Mediterranean greenhouse. Integrated physiological, metabolite, and transcriptomic analyses revealed that CF mitigated drought‑induced changes, suppressing about half of water‑stress responsive genes, thereby reducing the plant’s transcriptional sensitivity to water scarcity.
The study profiled root transcriptomes of Arabidopsis wild type and etr1 gain-of-function (etr1-3) and loss-of-function (etr1-7) mutants under ethylene or ACC treatment, identifying 4,522 ethylene‑responsive transcripts, including 553 that depend on ETR1 activity. ETR1‑dependent genes encompassed ethylene biosynthesis enzymes (ACO2, ACO3) and transcription factors, whose expression was further examined in an ein3eil1 background, revealing that both ETR1 and EIN3/EIL1 pathways regulate parts of the network controlling root hair proliferation and lateral root formation.
The autophagy-related genes AtATG5 and AtATG7 influence reserve mobilisation and responses to ABA during seed germination in Arabidopsis thaliana
Authors: Contreras, E., Sanchez-Vicente, I., Pastor-Mora, E., Aylon-Rodriguez, M., Gonzalez-Ceballos, M., Delgado-Gutierrez, M. A., Lorenzo, O., Vicente-Carbajosa, J., Iglesias-Fernandez, R.
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.
The study investigated how Arabidopsis thaliana SR protein kinases (AtSRPKs) regulate alternative RNA splicing by using chemical inhibitors of SRPK activity. Inhibition with SPHINX31 and SRPIN340 caused reduced root growth and loss of root hairs, accompanied by widespread changes in splicing and phosphorylation of genes linked to root development and other cellular processes. Multi‑omics analysis (transcriptomics and phosphoproteomics) revealed that AtSRPKs modulate diverse splicing factors and affect the splicing landscape of numerous pathways.
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.
The study reveals that root hair-forming trichoblast cells in Arabidopsis thaliana display higher autophagic flux than adjacent atrichoblast cells, a difference linked to cell fate determination. Elevated autophagy in trichoblasts is required for vacuolar sodium sequestration, contributing to salt‑stress tolerance, whereas disrupting autophagy in these cells impairs ion accumulation and survival. Cell‑type‑specific genetic complementation restores both autophagy and stress resilience, highlighting a developmental program that tailors autophagy for environmental adaptation.
Bacteria use processing body condensates to attenuate host translation during infection
Authors: Gonzalez-Fuente, M., Schulz, N., Abdrakhmanov, A., Izzati, G., Zhu, S., Langin, G., Gouguet, P., Franz-Wachtel, M., Macek, B., Hafren, A., Dagdas, Y., Üstün, S.
The study reveals that the bacterial pathogen Pseudomonas syringae suppresses host plant translation by targeting processing bodies (P‑bodies) through two liquid-like effectors, linking this repression to the ER stress response. It further demonstrates that autophagic clearance of P‑bodies is essential for balancing translationally active and inactive mRNAs, uncovering new connections among translation, ER stress, and autophagy during plant immunity.
The study investigates the role of the Arabidopsis transcription factor AtMYB93 in sulfur (S) signaling and root development, revealing that AtMYB93 mutants exhibit altered expression of S transport and metabolism genes and increased shoot S levels, while tomato plants overexpressing SlMYB93 show reduced shoot S. Transcriptomic profiling, elemental analysis, and promoter activity assays indicate that AtMYB93 contributes to root responses to S deprivation, though functional redundancy masks clear phenotypic effects on lateral and adventitious root formation.