Brt9SIDA/IDALs as peptide signals mediate diverse biological pathways in plants

As signal molecules, plant peptides play key roles in intercellular communication during growth and development, as well as stress responses. The 14-amino-acid (aa) INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) peptide was originally identified to play an essential role in the floral organ abscission of Arabidopsis. It is synthesized from its precursor, a small protein containing 77-aa residues with an N-terminal signal peptide sequence. Recently, the IDA/IDA-like (IDLs) genes are isolated in several angiosperms and are highly conserved in land plants. In addition, IDA/IDLs are not only involved in organ abscission but also function in multiple biological processes, including biotic and abiotic stress responses. Here, we summarize the post-translational modification and proteolytic processing, the evolutionary conservation, and the potential regulatory function of IDA/IDLs, and also present future perspectives to investigate the IDA/IDLs signaling pathway. We anticipate that this detailed knowledge will help to improve the understanding of the molecular mechanism of plant peptide signaling.