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.
The study reconstructed the evolutionary history of plant-specific GBF1-type ARF-GEFs by building phylogenetic trees and ortho‑synteny groups, identifying orthologs of AtGNOM and AtGNL1 across species. Functional analyses using transgenic Arabidopsis lines and yeast two‑hybrid assays revealed how duplication and loss events diversified GNOM paralogs, separating polar recycling from secretory trafficking functions.
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.
Rapid population flux in bacterial spot xanthomonads during a transition in dominance between two genotypes in consecutive tomato production seasons and identification of a new species Xanthomonas oklahomensis sp. nov.
Authors: Johnson, B., Subedi, A., Damicone, J., Goss, E., Jones, J. B., Jibrin, M. O.
The study examined Xanthomonas strains causing bacterial spot on tomato in Oklahoma fields during 2018‑2019, revealing a shift from X. euvesicatoria pv. euvesicatoria (Xee) to X. euvesicatoria pv. perforans (Xep) race T4, which also expanded to pepper. Phenotypic assays and whole‑genome sequencing highlighted differences in race composition, host range, copper sensitivity, and effector repertoires, and identified a novel species, Xanthomonas oklahomensis.
The authors conducted a comprehensive phylogenetic and sequence analysis of the conserved YUCCA (YUC) gene family across representative plant lineages, classifying the family into six major classes and 41 subclasses. They linked YUC diversification to protein sequence conservation and spatial/temporal gene expression patterns, providing a framework for future functional investigations of auxin biosynthesis.
The study analyzes ancient maize genomes from a 500–600 BP Bolivian offering and compares them with 16 archaeological samples spanning 5,000 years and 226 modern Zea mays lines, revealing close genetic affinity to ancient Peruvian maize and increased diversity during Inca‑local interactions. Phylogenetic and phenotypic analyses of ovule development indicate targeted breeding for seed quality and yield, suggesting culturally driven selection was already established by the 15th century CE.
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.
Using a barley pangenome of 76 genotypes and a pan‑transcriptome subset of 20, the study characterizes the diversity and evolutionary dynamics of CCT motif genes, uncovering novel frameshift variants and clade‑specific domain expansions. Phylogenetic and tissue‑specific expression analyses reveal functional divergence among paralogs, and the unexpected retention of the VRN2 repressor in spring barley suggests additional regulatory mechanisms beyond vernalization.
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.
Phylogenetic analysis reveals that non‑seed plants, exemplified by the liverwort Marchantia polymorpha, possess a streamlined repertoire of cyclin and CDK genes, with only three cyclins active in a phase‑specific manner during vegetative development. Single‑cell RNA‑seq and fluorescent reporter assays, combined with functional overexpression studies, demonstrate the distinct, non‑redundant roles of MpCYCD;1, MpCYCA, and MpCYCB;1 in G1 entry, S‑phase progression, and G2/M transition, respectively.