Genome-wide Identification of <i>Phloem Protein 2</i> Genes ( <i>PP2</i> s) and Characterization of <i>GhPP2</i> - <i>43</i> in <i>Verticillium wilt</i> Resistance of Cotton ( <i>Gossypium hirsutum</i> )

Phloem protein 2 (PP2) performs a vital function in plant stress response. Verticillium wilt is a destructive vascular disease that leads to significant reductions in cotton yield. However, limited systematic investigation has been conducted on the responsiveness of PP2 to V. wilt in cotton. Here, we identified a total of 46 GhPP2 s from the genome of Gossypium hirsutum . Among them, 41 GhPP2 s exhibited differentially expression during infection by Verticillium dahliae, with an AtPP2 - A1 homologue, GhPP2-43 displaying a pronounced response, indicating their potential roles in V. wilt resistance. Furthermore, GhPP2-43 may interact with peroxidase GhPER24 and ribosomal protein L18 (GhRPL18), potentially serving as a key regulator for enhancing cotton’s defense to V. wilt by improving a burst of reactive oxygen species (ROS) and its involvement in phytohormone signaling pathways. These findings offer valuable insights into GhPP2 s and indicate potential molecular targets for improving resistance against V. wilt in cotton.