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 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 authors compiled and standardized published data on Rubisco dark inhibition for 157 flowering plant species, categorizing them into four inhibition levels and analyzing phylogenetic trends. Their meta‑analysis reveals a complex, uneven distribution of inhibition across taxa, suggesting underlying chloroplast microenvironment drivers and providing a new resource for future photosynthesis improvement efforts.
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.
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.
The study used CRISPR/Cas9 to generate rice snrk1 mutants and performed integrated phenotypic, transcriptomic, proteomic, and phosphoproteomic analyses under normal and starvation conditions, revealing SnRK1’s dual role in promoting growth and mediating stress responses. Findings indicate sub-functionalization of SnRK1 subunits and identify novel phosphorylation targets linked to membrane trafficking, ethylene signaling, and ion transport.
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 reveals that the plant immune regulator NPR1 is modulated by opposing post‑translational modifications mediated by the nutrient‑sensing kinases TOR and SnRK1. Under normal conditions TOR phosphorylates NPR1 at Ser‑55/59 to suppress its activity, while salicylic‑acid‑induced SnRK1 activation inhibits TOR and phosphorylates NPR1 at Ser‑557, thereby activating NPR1 and linking metabolic status to immune signaling.