Genetius

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.

The study shows that inoculating Arabidopsis thaliana with the plant‑growth‑promoting bacterium Enterobacter sp. SA187 markedly boosts root and shoot biomass under elevated CO₂, accompanied by altered nitrogen and carbon content and reshaped phytohormone signaling. Transcriptomic and metabolomic analyses reveal activation of salicylic acid, jasmonic acid, and ethylene pathways and enhanced primary metabolism, while the ethylene‑insensitive ein2‑1 mutant demonstrates that the growth benefits are ethylene‑dependent.

The study combined cell biology, transcriptomics, and ionomics to reveal that zinc deficiency reduces root apical meristem size while preserving meristematic activity and local Zn levels, leading to enhanced cell elongation and differentiation in Arabidopsis thaliana. ZIP12 was identified as a highly induced gene in the zinc‑deficient root tip, and zip12 mutants displayed impaired root growth, altered RAM structure, disrupted Zn‑responsive gene expression, and abnormal metal partitioning, highlighting ZIP12’s role in maintaining Zn homeostasis and meristem function.

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 study used proximity labeling, co‑immunoprecipitation, and fluorescence microscopy to dissect the protein components and pathways governing distinct extracellular vesicle (EV) subpopulations in Arabidopsis, identifying roles for EXO70 exocyst subunits, RIN4, and VAP27. Mutant analyses revealed that disruptions in exo70 family genes, rin4, rabA2a, scd1, and vap27 reduce EV secretion and increase susceptibility to the fungal pathogen Colletotrichum higginsianum, highlighting EV secretion as a key facet of plant immunity.

The study investigates the conserved EDVID motif in the coiled‑coil domain of plant CC‑NLR immune receptors, revealing its role as a predictor of canonical CC‑NLR function and oligomeric assembly. It identifies a preceding acidic “preEDVID” motif in certain Arabidopsis‑related CC‑NLRs and shows that loss of the EDVID motif defines a distinct NLR subgroup, while acidic residues in the helper NLR NRG1.1 are crucial for cell‑death activity.

The authors engineered a novel ethylene‑responsive promoter (EBSn) containing ten divergent natural EIN3‑binding sites and demonstrated that it provides higher sensitivity and broader tissue expression than existing reporters in Arabidopsis thaliana. The EBSn promoter successfully monitored endogenous ethylene levels and also functioned in tomato, suggesting utility for studying ethylene‑regulated processes such as fruit ripening.

The study used Arabidopsis thaliana mutants with low (vtc2, vtc4) and high (vtc2/OE-VTC2) ascorbate levels to examine how ascorbate concentration affects gene expression and cellular homeostasis. Transcriptomic analysis revealed that altered ascorbate levels modulate defense and stress pathways, and that TAA1/TAR2‑mediated auxin biosynthesis is required for coping with elevated ascorbate in a light‑dependent manner.

The study identifies the RNA‑binding protein AtG3BP1 as a phosphorylation target of MAPKs MPK3, MPK4, and MPK6 at Ser257 in Arabidopsis thaliana and shows that this modification promotes susceptibility to bacterial pathogens, suppresses ROS accumulation and salicylic acid biosynthesis, and maintains stomatal opening. Phospho‑mimic and phospho‑dead mutants reveal that phosphorylation stabilizes AtG3BP1 by preventing proteasomal degradation, highlighting a novel post‑translational control layer in plant immunity.

The study reveals that Arabidopsis actin depolymerization factors (ADF2/3/4) have a nuclear moonlighting role, directly interacting with WRKY transcription factors to regulate immune‑related gene expression. Nuclear, rather than cytosolic, ADFs are essential for defense against both virulent and avirulent Pseudomonas syringae, highlighting a non‑canonical mechanism linking actin dynamics to transcriptional control in plant immunity.