Exogenous Hormone Treatments Reveal Species-Specific Regulation of Individual Components of Root Architecture and Salt Ion Accumulation in Cultivated and Wild Tomatoes
Authors: Rahmati-Ishka, M., Craft, E., Pineros, M., Julkowska, M. M.
The study examined how individual hormone treatments (auxin, ethylene, gibberellin) influence root architecture and ion accumulation under salt stress in three tomato accessions, revealing species-specific hormonal effects on lateral root development and Na/K ratios. Genetic analyses using Arabidopsis mutants and a tomato ethylene‑perception mutant (nr) identified novel hormonal signaling components that modulate salt stress responses, highlighting potential strategies to improve crop performance.
The study performs a bibliometric analysis of 1,702 Scopus-indexed tomato omics publications over two decades, revealing a rapid surge in output after 2017 and highlighting dominant fields such as biochemistry, genetics, and molecular biology. Citation and co‑authorship network analyses identify key contributions in microRNA research and genome sequencing, major research hubs, and collaborative clusters, while keyword mapping underscores stress response, fruit quality, and immunity as priority topics.
The study characterizes the tomato class B heat shock factor SlHSFB3a, revealing its age‑dependent expression in roots and its role in enhancing lateral root density by modulating auxin homeostasis. Overexpression of SlHSFB3a increases lateral root emergence, while CRISPR‑mediated knockouts produce the opposite phenotype, indicating that SlHSFB3a regulates auxin signaling through repression of auxin repressors and activation of the ARF7/LOB20 pathway.
The study investigated how plant roots promote water infiltration through dry soil layers using dye tracing in model soil microcosms. Results indicate that dissolved root exudates, possibly by altering surface tension, are the primary drivers of infiltration, with root architecture also contributing. These insights suggest that root traits influencing exudation and structure could improve drought resistance in crops.
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 examined how altering ethylene biosynthesis (ACO1) or perception (etr1.1) in a hybrid poplar (P. tremula × P. tremuloides T89) influences the assembly of root and shoot fungal and bacterial communities, using amplicon sequencing and confocal microscopy. Ethylene modulation had limited impact on the sterile plant metabolome but triggered distinct primary and secondary metabolic changes in microbe‑colonized plants, correlating with reduced fungal colonisation of shoots and increased root fungal colonisation, while arbuscular mycorrhizal fungi and bacterial communities were largely unchanged.
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 functionally characterizes three tomato CNR/FWL proteins (SlFWL2, SlFWL4, SlFWL5) and demonstrates that SlFWL5 localizes to plasmodesmata, where it regulates leaf size and morphology by promoting cell expansion likely through cell‑to‑cell communication. Gain‑ and loss‑of‑function transgenic tomato lines reveal that SlFWL5 is a key regulator of organ growth via modulation of plasmodesmatal signaling.
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 develops an updated genome-scale metabolic model of tomato leaf (CBZ_iSL3433) incorporating carbamazepine (CBZ) transformation reactions to simulate the pollutant's stress impact under phototrophic conditions. Constraint-based analysis predicts significant reductions in biomass and altered fluxes in nutrient assimilation and secondary metabolism, which are largely ameliorated by biostimulants such as proline, spermine, glycerol, and ethanol. This framework demonstrates a systems-level approach for screening strategies to mitigate pharmaceutical pollutant stress in crops.