Figure 4

Effect of phosphite on induction of auxin responsive genes. Relative expression ratios of AUX1, AXR1, AXR2 and SGT1B transcripts in Arabidopsis thaliana wild ecotype (Col-0) and mutants (aba2-4 and tir1-1) grown in a phosphate (Pi) sufficient medium (1.25 mM) for three weeks following further five days growth in different Pi (1.25 mM Pi; +Pi and 0 mM Pi; −Pi) and phosphite (Phi) (0, 0.5, 2.5 and 20 mM) levels. The transcript levels in the mutant were normalized based on the expression of actin 2 (ACT2) measured in the same samples and presented relative to the normalized expression levels in non-Phi treated, Pi-sufficient grown Col-0. Data represent the mean and standard error of four replicates of three plants each. The numbers on each bar indicate the fold increase/decrease in transcript levels relative to corresponding Pi sufficient (+Pi), non-Phi-treated plants. ANOVA indicated a significant (P < 0.05) difference between treatments for all genotypes. LSD (5%) for SGT1B, AXR1, AXR2, and AUX1 were 1.06, 1.25, 1.16, and 0.82 respectively.