The circadian clock gates lateral root development
Authors: Nomoto, S., Mamerto, A., Ueno, S., Maeda, A. E., Kimura, S., Mase, K., Kato, A., Suzuki, T., Inagaki, S., Sakaoka, S., Nakamichi, N., Michael, T. P., Tsukagoshi, H.
The study identifies the circadian clock component ELF3 as a temporal gatekeeper that limits hormone‑induced pericycle proliferation and lateral root development in Arabidopsis thaliana. Time‑resolved transcriptomics, imaging, and genetic analyses show that ELF3 maintains rhythmic expression of key regulators via LNK1 and MADS‑box genes, and that loss of ELF3 disrupts this rhythm, enhancing callus growth and accelerating root organogenesis.
The study reveals that the thermosensor and circadian regulator ELF3 interacts with the PLT3 transcription factor in Arabidopsis root stem cell niches, forming subcellular condensates that sustain quiescent centre and columella stem cell fate. ELF3’s intrinsically disordered prion‑like domains drive condensate formation with PLT3, and PIF3/4 act as nuclear shuttles recruiting ELF3 to nuclear condensates, linking environmental cues to stem cell maintenance.
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.
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 ELF4 is essential for recruiting ELF3 into hypocotyl nuclei at dusk, a process that enhances ELF3’s ability to repress target gene expression and limit hypocotyl elongation, especially under short‑day conditions. Subnuclear localization patterns of ELF3 differ between hypocotyl and root tissues, indicating tissue‑specific temporal regulation by ELF4.
The study investigates how cortical microtubule orientations are coordinated across tissues, testing the hypothesis that they sense mechanical stress. By quantifying microtubule behavior on different cell faces and edges, the authors find that tissue-level biases arise from cell‑geometric factors and edge‑specific mechanisms rather than direct stress sensing, and they develop a combinatorial model incorporating face‑specific and edge‑specific microtubule dynamics to explain the observed coordination.
The study genotyped 1,013 hard red spring wheat lines using SNP arrays and targeted KASP markers to track changes in genetic diversity and the distribution of dwarfing Rht alleles over a century of North American breeding. It found shifts from Rht‑D1b to Rht‑B1b dominance, identified low‑frequency dwarf alleles at Rht24 and Rht25 that have increased recently, and revealed gene interactions that can fine‑tune plant height, along with evidence of recent selection for photoperiod sensitivity.
The study isolated the Plant Cysteine Oxidase/Ethylene Response Factor VII oxygen‑sensing circuit from Arabidopsis thaliana and reconstituted it in Saccharomyces cerevisiae, using a reporter to compare hypoxia‑induced transcriptional dynamics in yeast and plants. Both systems showed rapid ERFVII stabilization, but plants exhibited a larger response, which could be enhanced in yeast by adding a hypoxia‑inducible feedback loop. Computational modeling identified promoter competition and hypoxia‑inducible PCOs as key determinants of early hypoxia responses.
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.