Impact of the down-regulation of <i>SlARF2A</i> and <i>SlARF2B</i> on auxin response assessed <i>in planta</i> following genetic crosses between DR5::GUS and <i>SlARF2</i> down-regulated lines.

<p>(A) Expression pattern of the GUS reporter gene under the control driven by the auxin-inducible DR5 promoter in wild type (WT) and <i>SlARF2</i> down-regulated genetic background. Seedlings were treated with auxin (IAA 20 μM for 3 hours) or with a mock solution. Upper panel: <i>in planta</i> expression of the GUS reporter gene driven by DR5 in WT genetic background in the absence (left) or presence (right) of auxin treatment. Bottom panel: Expression of the GUS reporter gene driven by DR5 in <i>ARF2A RNAi</i> (left), <i>ARF2B RNAi</i> (middle) and <i>ARF2AB RNAi</i> (right) genetic background. (B) Quantitative RT-PCR expression analysis of <i>GUS</i> and <i>SlARF2A/2B</i> genes in WT and <i>SlARF2A</i> and <i>SlARF2B-RNAi</i> lines crossed with DR5::GUS lines. The relative mRNA levels of <i>GUS-1/GUS-2</i> (Upper panel) and <i>SlARF2A/2B</i> (bottom panel) in wild type were standardized to 1.0, referring to the <i>SlActin</i> gene as internal control. Error bars mean ±SD of three biological replicates. *0.01 < p-value < 0.05. DR5-WT = DR5::GUS/WT; DR5-2A = DR5::GUS/ARF2A RNAi; DR5-2B = DR5::GUS/ARF2B RNAi; DR5-2AB = DR5::GUS/ARF2AB RNAi. <i>GUS-1</i> and <i>GUS-2</i> refer to the use of two distinct pairs of primers designed in two distinct regions of the GUS mRNA sequence.