Enhanced phosphate bioavailability and improving fatty acid composition in transgenic Brassica napus expressing...

Brassica napus is a major source of vegetable oil, with productivity strongly dependent on efficient phosphate ion (Pi) acquisition. Improving Pi uptake and homeostasis seems to be essential for enhancing biomass and seed oil quality. In this study, we generated a set of 41 transgenic B. napus events carrying inducible, overexpressed AtPAP17 gene while using an improved ptxD/phosphite selection system. This provided a unique collection of genetically related plants with a wide range of variations in Pi content, which were subjected to 0.25 mM KH2PO4, 2.5 mM KH2PO4 or KH₂PO₃ treatments. Variations among the events are likely due to differences in transgene positional effects, gene silencing and minor genetic background differences. The analyses of compiled phenotypic and biochemical datasets revealed a positive correlation between Pi homeostatic level and biomass in the transgenic plants, highlighting the remarkable role of AtPAP17 gene in enhancing Pi acquisition from extracellular resources. Furthermore, AtPAP17 overexpression appeared to support intracellular Pi recycling, contributing to the improved homeostasis. Notably, the selected transgenic plants showed improved biomass indices, increased seed yield and favourable changes in fatty acid composition, indicating broader metabolic impacts. These findings highlight AtPAP17 as a promising candidate gene for improving Pi use efficiency, biomass production and seed oil quality in B. napus.