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 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.
Wounding activates the HSFA1 transcription factors to promote cellular reprogramming in Arabidopsis
Authors: Coleman, D., Iwase, A., Kawamura, A., Takebayashi, A., Jaeger, K. E., Peng, M., Kodama, Y., Favero, D. S., Takahashi, T., Ikeuchi, M., Suzuki, T., Ohama, N., Yamaguchi-Shinozaki, K., Wigge, P. A., De Veylder, L., Sugimoto, K.
The study identifies Arabidopsis HSFA1 transcription factors as critical regulators of wound‑induced callus formation and shoot regeneration, showing that loss of HSFA1 impairs, while overexpression enhances, cellular reprogramming. Time‑series RNA‑seq and ChIP‑seq reveal HSFA1 directly activates key reprogramming genes (WIND1, PLT3, ZAT6), and its activity is modulated by SIZ1‑mediated SUMOylation.
The study employed computational approaches to characterize the SUMOylation (ULP) machinery in Asian rice (Oryza sativa), analyzing phylogenetic relationships, transcriptional patterns, and protein structures across the reference genome, a population panel, and wild relatives. Findings reveal an expansion of ULP genes in cultivated rice, suggesting selection pressure during breeding and implicating specific ULPs in biotic and abiotic stress responses, providing resources for rice improvement.
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.
Elucidating tissue and sub-cellular specificity of the entire SUMO network reveals how stress responses are fine-tuned in a eukaryote
Authors: Sadanandom, A., Banda, J., Ghosh, S., Roy, D., Bishopp, A., Jones, A., Sharma, E., Sue-Ob, K., Clark, L., Band, L. R., Lilley, K. S., Bennett, M. J., Ingole, K., De Lucas, M., Bhosale, R.
The authors generated a comprehensive SUMO Cell Atlas for Arabidopsis roots, mapping the expression and subcellular localization of all SUMO proteins and proteases across different tissue types. They discovered that stress‑induced SUMO conjugation is primarily controlled by tissue‑specific regulation of the SUMO E2 ligase, and that distinct root tissues employ unique protease combinations in response to salt, osmotic, and biotic stresses, revealing how SUMOylation orchestrates root development and stress adaptation.
The study investigated how Arabidopsis thaliana SR protein kinases (AtSRPKs) regulate alternative RNA splicing by using chemical inhibitors of SRPK activity. Inhibition with SPHINX31 and SRPIN340 caused reduced root growth and loss of root hairs, accompanied by widespread changes in splicing and phosphorylation of genes linked to root development and other cellular processes. Multi‑omics analysis (transcriptomics and phosphoproteomics) revealed that AtSRPKs modulate diverse splicing factors and affect the splicing landscape of numerous pathways.
The study investigates the role of the Arabidopsis transcription factor AtMYB93 in sulfur (S) signaling and root development, revealing that AtMYB93 mutants exhibit altered expression of S transport and metabolism genes and increased shoot S levels, while tomato plants overexpressing SlMYB93 show reduced shoot S. Transcriptomic profiling, elemental analysis, and promoter activity assays indicate that AtMYB93 contributes to root responses to S deprivation, though functional redundancy masks clear phenotypic effects on lateral and adventitious root formation.
The study investigates the Arabidopsis ribosomal protein RPS6A and its role in auxin‑related root growth, revealing that rps6a mutants display shortened primary roots, fewer lateral roots, and defective vasculature that are not rescued by exogenous auxin. Cell biological observations and global transcriptome profiling show weakened auxin signaling and reduced levels of PIN auxin transporters in the mutant, indicating a non‑canonical function of the ribosomal subunit in auxin pathways.