(F) RALF23 inhibits flg22-induced MAMP-responsive FRK1 gene expression in a Pi content-dependent manner. Seedlings grown in either HP or LP media were treated with water or flg22 for 15 mins and roots were harvested. The relative expression of FRK1 was quantified via RT-qPCR. The data shown indicate the means ± SDs (n = 3, n refers to technical replicates); n.s., not significant; **, p < 0.01 (Student's t test). Data information: All experiments were repeated three times with similar results.  