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 authors demonstrate that the WAVE/SCAR complex component BRK1 localizes to plasmodesmata and primary pit fields in Arabidopsis, using a BRK1‑YFP reporter line. BRK1 enrichment coincides with regions of reduced propidium iodide staining and colocalizes with aniline blue‑stained callose, suggesting that ARP2/3‑dependent actin branching contributes to plasmodesmata permeability regulation alongside formin‑mediated linear actin.
The study examined the evolution of plasmodesmata density across an evolutionary gradient of Flaveria species ranging from C3 to C4 photosynthetic types using electron microscopy. It identified two discrete, stepwise increases in plasmodesmata frequency, with a marked enrichment at the mesophyll‑bundle sheath interface in C4-like and C4 species, suggesting that heightened cell‑to‑cell connectivity underpins the development of C4 metabolism.
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 performed transcriptome profiling of Cryptomeria japonica individuals from different geographic origins grown in three common gardens across Japan, assembling 77,212 transcripts guided by the species' genome. Using SNP-based genetic clustering and weighted gene co‑expression network analysis, they identified gene modules whose expression correlated with genetic differentiation, revealing that defense‑related genes are up‑regulated in Pacific‑side populations while terpenoid metabolism genes are higher in Sea‑of‑Japan populations, indicating local adaptation via regulatory changes.
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.