A Species-Specific Cluster of Defensin-Like Genes Encodes Diffusible Pollen Tube Attractants in Arabidopsis

• DOI: 10.1371/journal.pbio.1001449
• Publication Date: 2012-12-18T21:56:05Z
• Authors: Hidenori Takeuchi; Tetsuya Higashiyama
• Keywords: QH301-705.5; Molecular Sequence Data; Arabidopsis; Pollen Tube; Genes, Plant; Defensins; Diffusion; Evolution, Molecular; 03 medical and health sciences; Gene Expression Regulation, Plant; Amino Acid Sequence; Cysteine; Biology (General); Phylogeny; Ecotype; Ovule; 0303 health sciences; Lamiaceae; Arabidopsis Proteins; Recombinant Proteins; Gene Knockdown Techniques; Multigene Family; Mutation; Peptides; Research Article

Genes directly involved in male/female and host/parasite interactions are believed to be under positive selection. The flowering plant Arabidopsis thaliana has more than 300 defensin-like (DEFL) genes, which likely both natural immunity cell-to-cell communication including pollen–pistil interactions. However, little is known of the relationship between molecular evolution DEFL genes their functions. Here, we identified a recently evolved cluster A. demonstrated that these (cysteine-rich peptide [CRP810_1]) peptides, named AtLURE1 pollen tube attractants guiding tubes ovular micropyle. formed sole species-specific among compared its close relative, lyrata. No evidence for selection was detected orthologs, implying neutral genes. peptides were specifically expressed egg-accompanying synergid cells secreted toward funicular surface through Genetic analyses showed gametophytic mutants defective micropylar guidance (myb98, magatama3, central cell guidance) do not express peptides. Downregulation expression impaired precise attraction opening some populations ovules. Recombinant attracted at higher frequency lyrata tubes, suggesting species-preferential guidance. In support this idea, heterologous single Torenia fournieri sufficient guide T. embryo sac permit entry into it. Our results suggest unique male–female interaction multigene family, furthermore overcome interspecific barriers penetration.