The genome of the vining fern Lygodium microphyllum highlights genomic and functional differences between life phases of an invasive plant
Authors: Pelosi, J., Davenport, R., Kuo, L.-Y., Gray, L. N., Dant, A. J., Kim, E. H., Li, F.-W., Dlugosch, K. M., Krabbenhoft, T. J., Barbazuk, W. B., Sessa, E. B.
The study presents a chromosome-level reference genome for the invasive fern Lygodium microphyllum and compares the transcriptomic and epigenomic profiles of its haploid gametophyte and diploid sporophyte phases, revealing differential regulation of developmental genes and similar methylation patterns across tissues. Base‑pair resolution methylome data and freezing‑stress experiments show that each life phase employs distinct molecular pathways for stress response, emphasizing the importance of considering both phases in invasive‑species management.
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.
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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.
The study investigated unexpected leaf spot symptoms in Psa3‑resistant kiwifruit (Actinidia) germplasm, finding that Psa3 was detectable by qPCR and metabarcoding despite poor culturing. Metabarcoding revealed distinct bacterial community shifts in lesions versus healthy tissue, and whole‑genome sequencing identified diverse Pseudomonas spp. that, while not individually more pathogenic, could enhance Psa3 growth, suggesting pathogenic consortia on resistant hosts.