DECREASE IN DNA METHYLATION 1-mediated epigenetic regulation maintains gene expression balance required for heterosis in Arabidopsis thaliana
Authors: Matsuo, K., Wu, R., Yonechi, H., Murakami, T., Takahashi, S., Kamio, A., Akter, M. A., Kamiya, Y., Nishimura, K., Matsuura, T., Tonosaki, K., Shimizu, M., Ikeda, Y., Kobayashi, H., Seki, M., Dennis, E. S., Fujimoto, R.
The study demonstrates that the chromatin remodeler DDM1 is essential for biomass heterosis in Arabidopsis thaliana hybrids, as loss of DDM1 function leads to reduced rosette growth and extensive genotype‑specific transcriptomic and DNA methylation changes. Whole‑genome bisulfite sequencing revealed widespread hypomethylation in ddm1 mutants, while salicylic acid levels were found unrelated to heterosis, indicating that epigenetic divergence, rather than SA signaling, underpins hybrid vigor.
The study examined how soil phosphorus and nitrogen availability influence wheat root-associated arbuscular mycorrhizal fungal (AMF) communities and the expression of mycorrhizal nutrient transporters. Field sampling across two years combined with controlled pot experiments showed that P and N jointly affect AMF colonisation, community composition (with Funneliformis dominance under high P), and regulation of phosphate, ammonium, and nitrate transporters. Integrating metabarcoding and RT‑qPCR provides a framework to assess AMF contributions to crop nutrition.
The study compared aphid resistance and Barley Yellow Dwarf Virus (BYDV) transmission among three wheat varieties (G1, RGT Wolverine, RGT Illustrious). G1 emits the repellent 2‑tridecanone, restricts aphid phloem access, and shows reduced BYDV transmission, whereas RGT Wolverine limits systemic viral infection despite high transmission efficiency. The authors suggest breeding the two resistance mechanisms together for improved protection.
The study applied a progressive, sublethal drought treatment to Arabidopsis thaliana, collecting time‑resolved phenotypic and transcriptomic data. Machine‑learning analysis revealed distinct drought stages driven by multiple overlapping transcriptional programs that intersect with plant aging, and identified high‑explanatory‑power transcripts as biomarkers rather than causal agents.
Salt stress strongly suppresses root growth in Festuca rubra while sparing shoot development. Transcriptome profiling identified over 68,000 differentially expressed genes, with up‑regulated genes enriched in methionine, melatonin, and suberin biosynthesis and down‑regulated genes involved in gibberellin, ABA, and sugar signaling, indicating extensive hormonal and metabolic reprogramming. Paradoxical regulation of gibberellin and ethylene pathways suggests a finely tuned balance between growth and stress responses.
A copper-dependent, redox-based hydrogen peroxide perception in plants
Authors: Ishihama, N., Fukuda, Y., Shirano, Y., Takizawa, K., Hiroyama, R., Fujimoto, K. J., Ito, H., Nishimura, M., Yanai, T., Inoue, T., Shirasu, K., Laohavisit, A.
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.
The study examined how single and repeated mechanical disturbances (whole‑pot drops) affect leaf folding in Mimosa pudica, using chlorophyll fluorescence to track photosystem II efficiency and transcriptome profiling to identify responsive genes. A single drop mainly up‑regulated flavonoid biosynthesis genes, whereas multiple drops triggered broader biotic and abiotic stress pathways, indicating a shift in the plant’s gene regulatory network under repeated stress.
Enhancement of Arabidopsis growth by Enterobacter sp. SA187 under elevated CO2 is dependent on ethylene signalling activation and primary metabolism reprogramming
Authors: Ilyas, A., Mauve, C., Pateyron, S., Paysant-Le Roux, C., Bigeard, J., Hodges, M., de Zelicourt, A.
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 evaluated the genetically encoded redox biosensor roGFP2-Orp1 for monitoring extracellular redox dynamics in diverse land plants, revealing that re‑oxidation rates in the apoplast differ between Physcomitrium patens and Arabidopsis thaliana and are accelerated by immune activation. Comparisons across tip‑growing cells showed no intracellular redox gradient but a partially reduced extracellular sensor in Nicotiana tabacum pollen tubes, indicating species‑ and cell‑type‑specific oxidative processes.
The study examined five sequential organ abscission events in two cherry species, revealing that some abscission zones form de novo while others are pre‑formed and reactivated by localized ethylene signaling, leading to cell division, lignification, ROS accumulation, and pH changes. Species‑specific differences were found in petal shedding and a post‑fertilization checkpoint that eliminates small fruits, indicating a hierarchical, multilayered reproductive filter controlling fruit set.