The study investigates the gene regulatory network (GRN) controlling flowering time in the allotetraploid crop Brassica napus by comparing its transcriptome to that of Arabidopsis thaliana. While most orthologous gene pairs show conserved expression dynamics, several flowering‑time genes display regulatory divergence, especially under cold conditions, indicating subfunctionalisation among paralogues. Despite these differences, the overall GRN topology remains similar to Arabidopsis, likely due to retention of multiple paralogues.
The study examined chromosomal evolution across 230 Andropogoneae species using literature/database surveys and phylogenetic analysis of complete plastome sequences, with Bayesian inference for ancestral state reconstruction. It found extensive chromosome-number variation (2n = 8–140), 30% polyploidy, and identified 2n = 20 as the likely ancestral state, highlighting the dynamic nature of chromosomal changes in the tribe.
The origins and adaptive consequences of polyploidy in a dominant prairie grass
Authors: Phillips, A. R., AuBuchon-Elder, T., Barry, K. W., Stitzer, M. C., Buckler, E. S., Bukowski, R., Cameron, B., Cryan, E., Forrestel, E., Grabowski, P. P., Grimwood, J., Jenkins, J. W., Shu, S., Lipzen, A., Lovell, J. T., Minx, P., Porter, J., Runcie, D. E., Schmutz, J., Solomon, B., Stephens, J., Sun, Q., Williams, M., Yoshinaga, Y., Flint-Garcia, S., Romay, C., Kellogg, E. A., Ross-Ibarra, J.
The study combined genomic and phenotypic approaches to investigate why polyploid grasses are abundant in North American prairies, focusing on the mixed‑ploidy grass Andropogon gerardi. A newly phased allopolyploid reference genome revealed that the hexaploid lineage arose during early Pleistocene glacial cycles, and that recurrent neopolyploidy (9x) events produce individuals with higher growth and reduced stomatal pore index, traits advantageous in xeric habitats, supporting both the opportunity and fitness‑advantage hypotheses for polyploid prevalence.
The study used comparative transcriptomics of dorsal and ventral petals across development, alongside expression profiling in floral symmetry mutants, to identify genes linked to dorsal (AmCYC-dependent) and ventral (AmDIV-dependent) identities in Antirrhinum majus. In situ hybridisation validated axis‑specific and boundary‑localized expression patterns, revealing that a conserved NGATHA‑LIKE1‑BRASSINAZOLE‑RESISTANT1‑miR164 module has been co‑opted to regulate AmDIV targets and shape the corolla. These findings delineate regulatory modules coordinating dorsoventral and proximal‑distal patterning in zygomorphic flowers.
The study sequenced genomes of ericoid mycorrhiza‑forming liverworts and experimentally reconstituted the symbiosis, revealing a nutrient‑regulated state that supports intracellular colonization. Comparative transcriptomics identified an ancestral gene module governing intracellular symbiosis, and functional validation in Marchantia paleacea through genetic manipulation, phylogenetics, and transactivation assays confirmed its essential role. The findings suggest plants have retained and independently recruited this ancestral module for diverse intracellular symbioses.
In a two-year controlled-environment experiment, diploid and tetraploid individuals of wild-type and cultivar Marshall annual ryegrass (Lolium multiflorum) were grown under elevated CO2 (540 vs 800 ppm) and differing evapotranspiration regimes. Elevated CO2 increased total biomass by 44% across ploidy levels, and tetraploid wild-type plants matched the improved cultivar in growth and forage quality, indicating that chromosome manipulation and wild genetic resources can enhance climate resilience.
High-quality PacBio HiFi draft genome assemblies were generated for three Bouteloua species (B. curtipendula, B. gracilis, B. eriopoda) with >98.5% BUSCO completeness. Gene prediction with Helixer produced inflated gene counts likely reflecting polyploidy and fragmented predictions, and panEDTA identified 25–40% transposable-element content dominated by LTR retrotransposons. These assemblies provide foundational references for comparative genomics within PACMAD grasses.
Phylogenomic challenges in polyploid-rich lineages: Insights from paralog processing and reticulation methods using the complex genus Packera (Asteraceae: Senecioneae)
Authors: Moore-Pollard, E. R., Ellestad, P., Mandel, J.
The study examined how polyploidy, hybridization, and incomplete lineage sorting affect phylogenetic reconstructions in the genus Packera, evaluating several published paralog‑processing pipelines. Results showed that the choice of orthology and paralog handling methods markedly altered tree topology, time‑calibrated phylogenies, biogeographic histories, and detection of ancient reticulation, underscoring the need for careful methodological selection alongside comprehensive taxon sampling.
The study found that facultative pseudogamous gametophytic apomixis is the predominant reproductive mode in natural populations of the polyploid fruit tree Psidium cattleyanum f. lucidum in Uruguay, with the proportion of apomictic versus sexual reproduction varying among populations and ploidy levels. Flow cytometric seed screening combined with microsatellite genotyping revealed mainly clonal progeny that nonetheless retain high genetic variability and strong population structure, indicating that ploidy influences reproductive strategy and genetic patterns.
The study used comparative transcriptomics across Erysimum species to identify two 2‑oxoglutarate‑dependent dioxygenases, CARD5 and CARD6, responsible for the 14β‑ and 21‑hydroxylation steps in cardenolide biosynthesis in Erysimum cheiranthoides. Knockout mutants lacking these genes accumulated pathway intermediates, and transient expression in Nicotiana benthamiana confirmed their enzymatic functions, while structural modeling pinpointed residues linked to neofunctionalization.