Functional properties and expression quantitative trait loci for phosphate transporter GmPT1 in soybean.

Phosphate ( Pi) remobilization within a plant is critical for plant survival under Pi-limiting conditions. In this paper, a soybean Pi transporter gene, GmPT 1, was characterized. A marked induction of GmPT 1 transcript was observed in young leaves, mature leaves and lateral roots during long-term Pi starvation. Transgenic tobacco plants containing the GmPT 1 gene were obtained using an Agrobacterium-mediated transformation system. Compared with wild-type plants, transgenic plants showed significant increases in phosphorus-use efficiency ( PUE), photosystem II ( PSII) function, total dry weight and seed weight under Pi-deficient conditions. GmPT 1 expression levels and PUE were determined in a soybean recombinant inbred line population during a pot experiment that was conducted to measure chlorophyll fluorescence parameters, photosynthetic rate ( PN) and seed yield. Correlation analysis revealed that GmPT 1 expression levels had significantly positive correlations with seed yield, PUE, PN and the quantum yield of PSII primary photochemistry ( ΦPSII). Expression quantitative trait loci ( eQTL) mapping for GmPT 1 revealed two eQTLs, one of which coincided with both the physical location of GmPT 1 and a QTL associated with seed yield. These results suggest that GmPT 1 plays a role in Pi remobilization, and it may be possible to improve soybean seed yields under Pi-limiting conditions by modulating GmPT 1 expression levels. [ABSTRACT FROM AUTHOR]