Root-Suppressed Phenotype of Tomato Rs Mutant is Seemingly Related to Expression of Root-Meristem-Specific Sulfotransferases
Authors: Kumari, A., Gupta, P., Santisree, P., Pamei, I., Valluri,, S., Sharma, K., Venkateswara Rao, K., Shukla, S., Nama, S., Sreelakshmi, Y., Sharma, R.
The study characterizes a radiation‑induced root‑suppressed (Rs) mutant in tomato that displays dwarfism and pleiotropic defects in leaves, flowers, and fruits. Metabolite profiling and rescue with H2S donors implicate disrupted sulfur metabolism, and whole‑genome sequencing identifies promoter mutations in two root‑meristem‑specific sulfotransferase genes as likely contributors to the root phenotype.
The study investigates the role of the SNF1-related kinase 1 (SnRK1) in conferring quantitative resistance to clubroot disease caused by Plasmodiophora brassicae in Arabidopsis thaliana. Increased nuclear SnRK1 activity suppresses disease development by down‑regulating sucrose transporter and cell wall invertase expression and activity, thereby reducing sink strength, while the pathogen effector PBZF1 interferes with SnRK1 nuclear translocation.
An ancient alkalinization factor informs Arabidopsis root development
Authors: Xhelilaj, K., von Arx, M., Biermann, D., Parvanov, A., Faiss, N., Monte, I., Klingelhuber, F., Zipfel, C., Timmermans, M., Oecking, C., Gronnier, J.
The study identifies members of the REMORIN protein family as inhibitors of plasma membrane H⁺‑ATPases, leading to extracellular pH alkalinization that modulates cell surface processes such as steroid hormone signaling and coordinates root developmental transitions in Arabidopsis thaliana. This inhibition represents an ancient mechanism predating root evolution, suggesting that extracellular pH patterning has shaped plant morphogenesis.
The authors used a bottom‑up thermodynamic modelling framework to investigate how plants decode calcium signals, starting from Ca2+ binding to EF‑hand proteins and extending to higher‑order decoding modules. They identified six universal Ca2+-decoding modules that can explain variations in calcium sensitivity among kinases and provide a theoretical basis for interpreting calcium signal amplitude and frequency in plant cells.
The study demonstrates that trehalose‑6‑phosphate (T6P), a sucrose‑derived metabolite, acts as the central signal linking carbon availability to Target of Rapamycin (TOR) activation in plants. Using Arabidopsis and Brassica napus, the authors show that T6P is necessary for sucrose‑induced TOR activity and that it counteracts SnRK1‑mediated inhibition of TOR, establishing a sucrose‑T6P‑SnRK1‑TOR signaling axis that promotes cell growth.
The study examines how ectopic accumulation of methionine in Arabidopsis thaliana leaves, driven by a deregulated AtCGS transgene under a seed‑specific promoter, reshapes metabolism, gene expression, and DNA methylation. High‑methionine lines exhibit increased amino acids and sugars, activation of stress‑hormone pathways, and reduced expression of DNA methyltransferases, while low‑methionine lines show heightened non‑CG methylation without major transcriptional changes. Integrated transcriptomic and methylomic analyses reveal a feedback loop linking sulfur‑carbon metabolism, stress adaptation, and epigenetic regulation.
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 identifies and functionally characterizes an acetyl‑CoA:monolignol transferase gene in Populus, showing that its overexpression elevates acetate incorporation into lignin without harming plant growth. Elevated lignin acetylation correlates with gene expression levels and markedly improves biomass pretreatability for biofuel production.
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 reveals that the energy sensor SnRK1 modulates Arabidopsis defense by repressing SA‑dependent gene expression and bacterial resistance, with its activity enhanced under high humidity. SnRK1 interacts with TGA transcription factors to attenuate PR1 expression, linking cellular energy status to immune regulation.