Two PHOSPHATE-TRANSPORTER1 genes in cotton enhance tolerance to phosphorus starvation

Phosphorus is an essential macronutrient element for productivity of crop ecosystems. But orthophosphate (Pi), the direct uptake form by plants, is found in low solubility in soil, leading to plants often suffer from Pi starvation when they grow. High-affinity Pi transporters (PTs) play roles in Pi starvation response (PSR), and they are the main Pi influx machinery. Like most sessile plants, cotton is also threatened by Pi deficiency and has developed sophisticated PSR systems to cope with phosphorus deficiency. However, the regulation mechanism of Pi homeostasis is largely unknown in cotton. Here, we identified that two cotton PHOSPHATE-TRANSPORTER1 family genes, GhPHT1;4 and GhPHT1;5, were mainly responsible for Pi uptake under Pi-starvation conditions in cotton. Their promoter activities were significantly activated by Pi deficiency and the overexpression of two genes enhanced the Pi uptake under Pi-deficiency and Pi-normal conditions. Furthermore, we found that PHT1;4 and PHT1;5 participated in modifying root architecture during Pi-starvation, as well as affecting the PSR in plant. Thus, we identified that two cotton Pi transporters functioned in Pi homeostasis, which would provide new gene resources for sustainable agriculture.

Automated summary

Phosphorus is a vital nutrient for crop productivity, but its low solubility in soil often leads to phosphorus deficiency in plants. The study identified two cotton genes, GhPHT1;4 and GhPHT1;5, which play a role in phosphorus uptake and participate in root architecture modification and phosphorus starvation response in cotton.