Abstract

The phytohormone cytokinin has been shown to play a major role in plant development. To better understand the cytokinin response pathway in Prunus persica at specific stages of fruit development, we have identified two putative orthologs of the Arabidopsis cytokinin signaling pathway (ARR1 and ARR6) and a cytokinin/auxin crosstalk factor (SHY2). These orthologs have been named PpRR1, PpRR6 and PpSHY2, respectively. Exogenous application of t-zeatin increased the expression of PpRR6 at several stages of peach fruit development. In contrast, PpRR1 expression was inhibited by exogenously applying t-zeatin in a stage-specific manner. Expression of PpSHY2 increased or decreased depending upon the developmental stage being analyzed. We have performed RNA-seq and qPCR analyses of peach fruits treated with exogenously applied t-zeatin in order to further identify the developmental stage specific cytokinin response genes in peach fruits. Furthermore, transient overexpression analyses of PpRR1 in peach fruits, reveals that PpRR1 is sufficient to increase the expression of PpRR6 and PpSHY2. These results suggest that the cytokinin response pathway is conserved between Arabidopsis and Peach.