P-_WT_R1
We developed complementary DNA (cDNA) libraries deriving from 3-day-old seedling root tips growing on P+ or P- medium.Total RNA was purified from 8 root tip samples [(mutant and wild-type)  (two biological replicates)] using the RNeasy Plant Mini Kit (Qiagen).  RNA samples were quantified using NanoDrop 2000c Spectrophotometer (Thermo) and Qubit Fluorometer (Life Technology). Poly(A)+ RNA was selected by two rounds of hybridization to oligo(dT)-coated Dynal magnetic beads (Life Technology). Sequencing libraries were prepared from poly(A)+ RNA as described previously (Jiao and Meyerowitz, 2010). Libraries were sequenced as 50-mers using HiSeq2000 (Illumina) with standard settings.