Table SII.Phosphate starvation-induced (PSI) gene expression (mean ± SE) at 48 hpg under low (1 µM) phosphate conditions calculated vs. PSI gene expression under high (2 mM) phosphate conditions. Ratios were calculated for each of the genotypes (WT, max2-1 and max4-1) and treatments (IAA at 1x10-6M; GR24 at 15uM and AbamineSG at 1mM).For each replicate of the experiment controls were conducted, in which the exact concentration of the appropriate solvent was used to treat the seedlings (H2O for IAA, acetone for GR24 or AbamineSG). Values of the steady state level of gene transcripts were determined as a ratio between low Pi vs. high Pi conditions, using the method (Arocho et al., 2006; Livak and Schmittgen, 2001). Value above or below 1.5 represents increase or decrease, respectively, in the steady state level of gene transcripts for the examined conditions (i.e., that of the numerator versus that of the denominator) as described in the Material and Methods. RNA was extracted from seedlings of WT, max2-1 and max4-1 mutants, from control, GR24,AbamineSG and IAA treatments. Arabidopsis15S ribosomal RNA (GenBankaccession no. AT1G04270.1; Kapulnik et al., 2011) served as the reference gene for the amount of RNA. The experiment was performed in five biological replicates; each replicate included 120 plants, on which three technical repeats were performed. Means and standard error were determined from all biological replicates.

Treatment / Control / GR24 / AbamineSG / IAA
Gene/Genotype / WT / max2-1 / max4-1 / max4-1 / WT / max2-1
ACP5 ¥ / 473.46±47.50 / 32.02±6.33* / 79.55±23.70* / 11.44±5.05* / 47.06±7.40* / 266.66±112.74
IPS1 ¥ / 81.73±29.21 / 13.41±6.57* / ND / ND / ND / ND
PHT1;1 ¥ / 32.09±9.92 / 111.19±72.96 / ND / ND / ND / ND
PHT1;2 ¥ / 8.97±3.20 / 0.11±0.05* / 10.93±1.02 / 10.60±8.12 / 26.54±6.7 / 8.09±3.33
PHT1;4 ¥ / 114.53±33.52 / 3.24±0.63* / 2.36±1.05* / 83.78±30.08 / 0.154±0.026* / 7.02±0.48*
PHT1;5 ¥ / 2.41±0.40 / 0.32±0.19* / 1.48±0.54 / 201.25±97.04 / 1.05±0.025* / 3.89±0.58
TIR1 / 17.23±3.51 / 0.27±0.09* / 6.78±2.09 / 37.48±13.02 / 4.56±1.17* / 0.77±0.19*
PHO2 / 0.13±0.005 / 16.34±5.35* / ND / ND / ND / ND

¥PSI genes

* Means are statistically differentfrom that of the WT in the control treatment.