Divergent evolution of AWPM-19 from bryophytes to angiosperms and functional conservation of AtAWPM-19-1 and PtAWPM-19-4 in drought response

• A comprehensive analysis of the AWPM-19 gene family revealed distinct evolutionary patterns between non-seed plants and angiosperms. • PtAWPM-19-4 and AtAWPM-19-1 exhibit functional conservation, highlighting the potential of their orthologs in drought stress tolerance. The AWPM-19 gene family, originally identified as an ABA-induced 19-kDa polypeptide in wheat plasma membranes, is involved in stress response pathways, particularly in drought tolerance. However, comprehensive analyses of this gene family are scarce, and the functional characterization of its members remains limited. In this study, we performed genome-wide analysis of the AWPM-19 gene family across ten distantly related plant species, ranging from bryophytes to angiosperms. We analyzed their molecular features, motif compositions, cis-acting regulatory elements in promoters, evolutionary relationships, and synteny across species. The results revealed that AWPM-19 genes in Marchantia polymorpha, Physcomitrium patens and Selaginella moellendorffii clustered together, indicating close evolutionary relationships within non-seed plants. In contrast, genes from Amborella trichopoda, Nymphaea colorata, Arabidopsis thaliana, Brachypodium distachyon, Oryza sativa, Vitis vinifera and Populus trichocarpa showed higher sequence similarity and closer phylogenetic relationship. To explore the functional role of AWPM-19 genes, overexpression lines of PtAWPM-19-4 in Arabidopsis, atawpm-19-1 mutants, and PtAWPM-19-4/atawpm-19-1 complementation lines were generated. Functional analysis revealed both PtAWPM-19-4 and AtAWPM-19-1 are involved in drought tolerance. These findings provide new insights into the evolutionary conservation and functional relevance of AWPM-19 genes in plant drought stress adaptation.