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 shows that inoculation with the non‑diazotrophic bacterium Enterobacter sp. SA187 significantly improves Arabidopsis thaliana growth under low nitrate conditions by increasing fresh weight, primary root length, and lateral root density, while enhancing nitrate accumulation and reducing shoot C:N ratios. Transcriptomic and mutant analyses reveal that these benefits depend on ethylene signaling and the activity of high‑affinity nitrate transporters NRT2.5 and NRT2.6, indicating an ethylene‑mediated, HATS‑dependent reprogramming of nitrogen uptake.
Unravelling the intraspecific variation in drought responses in seedlings of European black pine (Pinus nigra J.F. Arnold)
Authors: Ahmad, M., Hammerbacher, A., Priemer, C., Ciceu, A., Karolak, M., Mader, S., Olsson, S., Schinnerl, J., Seitner, S., Schoendorfer, S., Helfenbein, P., Jakub, J., Breuer, M., Espinosa, A., Caballero, T., Ganthaler, A., Mayr, S., Grosskinsky, D. K., Wienkoop, S., Schueler, S., Trujillo-Moya, C., van Loo, M.
The study examined drought tolerance across nine provenances of the conifer Pinus nigra using high‑throughput phenotyping combined with metabolomic and transcriptomic analyses under controlled soil‑drying conditions. Drought tolerance, measured by the decline in Fv/Fm, varied among provenances but was not linked to a climatic gradient and was independent of growth, with tolerant provenances showing distinct flavonoid and diterpene profiles and provenance‑specific gene expression patterns. Integrating phenotypic and molecular data revealed metabolic signatures underlying drought adaptation in this non‑model conifer.
The study integrated 16 Arabidopsis thaliana whole‑genome bisulfite sequencing datasets from 13 stress experiments using a unified bioinformatic pipeline to map common and stress‑specific DNA methylation changes. Differentially methylated regions varied by stress type and methylation context, with CG DMRs enriched in gene bodies and CHG/CHH DMRs in transposable elements, some of which overlapped loci prone to stable epimutations. Gene ontology and TE enrichment analyses highlighted shared stress pathways and suggest environmental stress can generate heritable epigenetic variation.
The study reveals that Arabidopsis ethylene receptors ETR1 and ERS1 function as Ca²⁺-permeable channels, with ETR1 specifically mediating ethylene‑induced cytosolic Ca²⁺ spikes that influence hypocotyl elongation. Homologous receptors from diverse land plants and algae also show Ca²⁺ permeability, and ethylene further enhances this activity, indicating a conserved regulatory role across the green lineage.
Drought-Induced Epigenetic Memory in the cambium of Poplar Trees persists and primes future stress responses
Authors: DUPLAN, A., FENG, Y. Q., LASKAR, G., CAI, B. D., SEGURA, V., DELAUNAY, A., LE JAN, I., DAVIAUD, C., TOUMI, A., LAURANS, F., SOW, M. D., ROGIER, O., POURSAT, P., DURUFLE, H., JORGE, V., SANCHEZ, L., COCHARD, H., ALLONA, I., TOST, J., FICHOT, R., MAURY, S.
The study examined short‑term and transannual drought memory in cambium tissues of two Populus genotypes and four epitypes with modified DNA‑methylation machinery, revealing persistent hormone, transcript, and methylation changes one week after stress relief. Trees previously stressed in Year 1 displayed distinct physiological and molecular responses to a second drought in Year 2, indicating long‑term memory linked to stable CG‑context DNA methylation, with genotype‑dependent differences in plasticity and stability. These findings position the cambium as a reservoir for epigenetic stress memory and suggest exploitable epigenetic variation for tree breeding under drought.
The study demonstrates that ethylene signaling contributes to host resistance against the root parasitic plant Phelipanche aegyptiaca, as both water stress and parasitism activate ethylene responses in Arabidopsis roots. Application of the ethylene precursor ACC reduced parasite attachment, and mutants in ethylene signaling components (ETR1, CTR1) showed altered tolerance, highlighting ethylene-mediated defenses as a potential strategy for crop protection.
The study compared physiological and transcriptomic responses of poplar trees colonized by the ectomycorrhizal fungi Paxillus involutus or Cenococcum geophilum under normal, drought, and recovery conditions. Cenococcum-colonized plants showed constitutive up‑regulation of heat‑shock proteins, galactinol synthase, and aquaporins and maintained water status and photosynthesis during severe drought, whereas Paxillus colonization promoted growth and nitrogen‑use efficiency and enabled rapid recovery through drought‑induced leaf shedding. These contrasting strategies illustrate species‑specific positions on the growth‑defense trade‑off in ectomycorrhizal symbiosis.
The study uncovers a reciprocal regulatory loop between type one protein phosphatases (TOPPs) and EIN2 in ethylene signaling, showing that ethylene induces TOPPs expression and that TOPPs dephosphorylate EIN2 at S655 to stabilize it and promote nuclear accumulation. TOPPs act upstream of EIN2, while EIN3/EIL1 transcriptionally activates TOPPs, linking dephosphorylation to enhanced ethylene responses and improved salt tolerance.
The study used host-mediated artificial selection to iteratively enrich rice-associated microbiomes that improve growth and drought tolerance, starting from diverse soil microbial communities. Over multiple generations, selected microbiomes converged, and amplicon sequencing along with metagenome-assembled genomes identified specific bacterial taxa and functional pathways (e.g., glycerol-3-phosphate and iron transport) linked to enhanced drought performance. The results demonstrate the effectiveness of plant phenotype-driven microbiome engineering for crop improvement.