Early phosphate-deficiency induced signal changes in Arabidopsis roots

A mutant previously isolated from a screen of EMS-mutagenized Arabidopsis lines, per1, showed normal root hair development under control conditions but displayed an inhibited root hair elongation phenotype upon Pi deficiency. Additionally, the per1 mutant exhibited a pleiotropic phenotype under control conditions, resembling Pi-deficient plants in several aspects. Under Pi deficiency, the accumulation of Pi and iron was increased in the mutant when compared to the wild-type. Inhibition of root hair elongation upon growth on low Pi media was reverted by treatment with the Pi analog phosphite, suggesting that the mutant phenotype is not the result of a defect in Pi sensing. Reciprocal grafting experiments revealed that the mutant rootstock is sufficient to cause the phenotype. Transcriptional profiling of per1 and wild-type plants subjected to short-term Pi starvation revealed genes that may be important for the signaling of Pi deficiency. We conclude that UBP14 function is crucial for adapting root development to the prevailing local availability of phosphate. Col-0 and per1 mutant plants were grown under control conditions or subjected to phosphate starvation for 10 h