*4.3. P and N Crosstalk*

Phosphorus (P) is acquired by plants primarily in the form of inorganic phosphate (Pi) by Pi transporters (PHT). The *Nitrogen limitation adaptation* (*NLA*) gene is involved in adaptive responses to low-N stress in *Arabidopsis* [51] and is an important regulator of PHTs under N deficiency [52–55]. Over-expression of the rice Pi transporter gene OsPT2 enhances tolerance to Pi deficiency, as well as N2 fixation and ammonium assimilation [56,57]. These studies indicate the intimate crosstalk between the N limitation and P deficiency response pathways. In the present study, *Sodium-dependent phosphate transport protein 1* (*LOC107857112*) was repressed in the roots of 750-1, and *PHT1;2* (*LOC107866602*) and *PHT1;9* (*LOC107866766*) were up-regulated in the roots of ZCFB under low-N stress (Figure 7F), providing new information regarding the low-N induced crosstalk between N and P.
