Phosphite (Phi) and phosphate (Pi) share the same root uptake system, but Phi acts as a biostimulant that modulates plant growth and disease resistance in a species‑ and Pi‑dependent manner. In Arabidopsis, Phi induces hypersensitive‑like cell death and enhances resistance to Plectosphaerella cucumerina, while in rice it counteracts Pi‑induced susceptibility to Magnaporthe oryzae and Fusarium fujikuroi, accompanied by extensive transcriptional reprogramming.
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 study identified a heat‑responsive exon‑skipping event in the basic Helix‑Loop‑Helix domain of the transcription factor PIF4, which reduces PIF4 activity and promotes photomorphogenic traits in etiolated seedlings. This reveals a novel post‑transcriptional mechanism by which plants modulate PIF4 function during heat stress.
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 identifies two diel regulatory modules that coordinate plant cuticle formation: the LRB‑phyB‑PIF4 pathway suppresses wax biosynthesis during daylight, while the COP1‑CFLAP1 pathway promotes cutin accumulation at night. Degradation of phyB and CFLAP1 via specific E3 ubiquitin ligases modulates the activity of transcription factors PIF4 and BDG1 to ensure timely cuticle assembly.
The study shows that high ambient temperature triggers extensive changes in ROS homeostasis in Arabidopsis seedlings, with H2O2 balance being essential for thermomorphogenic hypocotyl elongation. PIF4 directly activates catalase genes CAT2 and CAT3 to regulate H2O2 levels, forming a PIF4‑CAT‑H2O2 module that operates alongside the PIF4‑auxin pathway, while elevated H2O2 feeds back to reduce PIF4 protein abundance.
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 shows that the SnRK1 catalytic subunit KIN10 directs tissue-specific growth‑defense programs in Arabidopsis thaliana by reshaping transcriptomes. kin10 knockout mutants exhibit altered root transcription, reduced root growth, and weakened defense against Pseudomonas syringae, whereas KIN10 overexpression activates shoot defense pathways, increasing ROS and salicylic acid signaling at the cost of growth.
The study examines how the SnRK1 catalytic subunit KIN10 integrates carbon availability with root growth regulation in Arabidopsis thaliana. Loss of KIN10 reduces glucose‑induced inhibition of root elongation and triggers widespread transcriptional reprogramming of metabolic and hormonal pathways, notably affecting auxin and jasmonate signaling under sucrose supplementation. These findings highlight KIN10 as a central hub linking energy status to developmental and environmental cues in roots.