Plasma membrane-localized BnaPHT1;4 J mediates phosphate uptake in Brassica napus L.

Phosphorus (P) is essential for Brassica napus L. (B. napus) growth and development, but most P in soil is unavailable. Evidence shows that BnaPHT1s react to a range of nutritional stresses and heavy metals. However, little is known about the mechanism of BnaPHT1s in B. napus. Therefore, the present study aimed to characterize the members of the BnaPHT1 in allotetraploid B. napus and to analyze their expression profile in response to environmental stresses. BnaPHT1;4 J is a member of the little-known mechanism in this regard. We used Xiaoyun (XY) to investigate the effect of BnaPHT1;4 J on phosphate (Pi) uptake.

In this study, we identified a novel member of PHT1;4 subfamily in B. napus, which is highly expressed in root under low Pi stress, and named it BnaPHT1;4 J. We further characterized the role of BnaPHT1;4 J for Pi uptake in B. napus. Quantitative RT-PCR, onion subcellular localization, and GUS expression analysis reveal that BnaPHT1;4 J is a membrane protein that is mainly localized at roots under low Pi conditions.

Phenotypic characterization showed that BnaPHT1;4 J overexpression under low Pi promoted root growth and main root elongation in Arabidopsis and B. napus, and other physiological indicators such as P content and biomass in B. napus were also positively regulated.

BnaPHT1;4 J has a catalytic effect on seedlings and nutritional growth of B. napus and promotes Pi uptake and translocation.