Tartary buckwheat cotyledon size varieties undergo distinct transcriptional reprogramming of phytohormone signaling under cold and UV stresses.

Small-cotyledon Tartary buckwheat (Fagopyrum tataricum) accessions show enhanced cold and UV-B stress tolerance, with lower MDA and higher POD, SOD, and CAT activities.

• Why it matters: The molecular link between cotyledon size and early abiotic stress resistance is unclear, limiting how seedling traits can be used to understand or improve tolerance.
• What they did: The study phenotyped 279 accessions across three ecological regions over two years, selected Ft104 and Ft32, then combined physiological assays, transcriptomics/WGCNA (18 modules), qRT-PCR, yeast expression, and targeted LC-MS/MS.
• The result: MEcoral4 was enriched in plant hormone signal transduction and linked to morphology and stress traits; FtPYL4 showed preliminary cold-tolerance evidence in yeast, while Ft32 accumulated more indole-related metabolites and SA under stress and Ft104 showed a stronger JA response to UV-B.