The Peach RGF/GLV Signalling Peptide pCTG134 Is Involved in a Regulatory Circuit That Sustains Auxin and Ethylene Actions

The study investigated the role of the peach gene CTG134, which encodes a peptide hormone (PH) involved in fruit ripening. CTG134 expression in peach fruit increased during the climacteric phase and was induced by auxin and 1-MCP treatments but was not significantly affected by ethylene. When CTG134 was overexpressed in Arabidopsis and tobacco, it led to abnormal root hair growth, which was similar to the effect of treating these plants with a synthetic version of the peptide. This overexpression also disrupted the hormonal crosstalk, altering the expression of genes related to both ethylene and auxin pathways. The use of a pCTG134 promoter fused with a GUS reporter indicated gene activity in plant organs where auxin-ethylene interactions are known to occur. These findings suggest that pCTG134 plays a role in mediating the regulatory circuit between auxin and ethylene hormones.