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.
Arabidopsis lines with modified ascorbate concentrations reveal a link between ascorbate and auxin biosynthesis
Authors: Fenech, M., Zulian, V., Moya-Cuevas, J., Arnaud, D., Morilla, I., Smirnoff, N., Botella, M. A., Stepanova, A. N., Alonso, J. M., Martin-Pizarro, C., Amorim-Silva, V.
The study used Arabidopsis thaliana mutants with low (vtc2, vtc4) and high (vtc2/OE-VTC2) ascorbate levels to examine how ascorbate concentration affects gene expression and cellular homeostasis. Transcriptomic analysis revealed that altered ascorbate levels modulate defense and stress pathways, and that TAA1/TAR2‑mediated auxin biosynthesis is required for coping with elevated ascorbate in a light‑dependent manner.
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 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.
The study generated two allotriploid Brassica hybrids (ArAnCn) to investigate asymmetric subgenome dominance, finding that the Cn subgenome dominates despite the An subgenome showing highest expression levels. Increased density of accessible chromatin regions (ACRs) in the Cn subgenome correlates with dominant gene expression, while changes in CHH methylation and specific RNA‑directed DNA methylation pathway mutants affect subgenome bias.
The study examined 57 global accessions of the invasive hybrid Kalanchoe xhoughtonii and its parents, revealing extensive cytogenetic and genomic variation among morphotypes but identifying a single tetraploid genotype (morphotype A) that dominates worldwide. This genotype exhibits remarkable genetic uniformity, high phenotypic plasticity, and prolific vegetative propagation, illustrating how hybridization and polyploidy can drive rapid invasive success.
Transcriptome responses of two Halophila stipulacea seagrass populations from pristine and impacted habitats, to single and combined thermal and excess nutrient stressors, reveal local adaptive features and core stress-response genes
Authors: Nguyen, H. M., Yaakov, B., Beca-Carretero, P., Procaccini, G., Wang, G., Dassanayake, M., Winters, G., Barak, S.
The study examined transcriptomic responses of the tropical seagrass Halophila stipulacea from a pristine and an impacted site under single and combined thermal and excess nutrient stress in mesocosms. Combined stress caused greater gene reprogramming than individual stresses, with thermal effects dominating and the impacted population showing reduced plasticity but higher resilience. Core stress‑response genes were identified as potential early field indicators of environmental stress.