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.
A comparative physiological study of persimmon cultivars with flat (Hiratanenashi) and round (Koushimaru) fruit shapes revealed that differences in cell proliferation, cell shape, and size contribute to shape variation. Principal component analysis of elliptic Fourier descriptors tracked shape changes, while histology and transcriptome profiling identified candidate genes, including a WOX13 homeobox gene, potentially governing fruit shape development.
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 investigates how fruit shape and pericarp permeability drive the water content trajectories that determine whether fruits become fleshy or dry at maturity, using a large-scale survey of 29,760 species and targeted water‑content measurements. It finds that fleshy fruits retain water longer due to globular shapes and waxy pericarps, while dry fruits lose water rapidly as lignification and increased permeability accompany elongated shapes, especially under open‑habitat conditions.
An EMS-induced round fruit (rf) mutant in woodland strawberry was found to carry a premature stop codon in the TRM5 homolog (FveTRM5), linking this gene to fruit shape regulation. Transgenic complementation restored the round phenotype, while overexpression in both strawberry and Arabidopsis caused organ elongation, indicating FveTRM5 promotes cell elongation and restricts medial‑lateral cell division via microtubule association. The study highlights FveTRM5 as a valuable target for breeding strawberry varieties with desired fruit shapes.