title: Tip-localized receptors control pollen tube growth and LURE sensing in Arabidopsis.
abstract: Directional control of tip-growing cells is essential for proper tissue organization and cell-to-cell communication in animals and plants. In the sexual reproduction of flowering plants, the tip growth of the male gametophyte, the pollen tube, is precisely guided by female cues to achieve fertilization. Several female-secreted peptides have recently been identified as species-specific attractants that directly control the direction of pollen tube growth. However, the method by which pollen tubes precisely and promptly respond to the guidance signal from their own species is unknown. Here we show that tip-localized pollen-specific receptor-like kinase 6 (PRK6) with an extracellular leucine-rich repeat domain is an essential receptor for sensing of the LURE1 attractant peptide in Arabidopsis thaliana under semi-in-vivo conditions, and is important for ovule targeting in the pistil. PRK6 interacted with pollen-expressed ROPGEFs (Rho of plant guanine nucleotide-exchange factors), which are important for pollen tube growth through activation of the signalling switch Rho GTPase ROP1 (refs 7, 8). PRK6 conferred responsiveness to AtLURE1 in pollen tubes of the related species Capsella rubella. Furthermore, our genetic and physiological data suggest that PRK6 signalling through ROPGEFs and sensing of AtLURE1 are achieved in cooperation with the other PRK family receptors, PRK1, PRK3 and PRK8. Notably, the tip-focused PRK6 accumulated asymmetrically towards an external AtLURE1 source before reorientation of pollen tube tip growth. These results demonstrate that PRK6 acts as a key membrane receptor for external AtLURE1 attractants, and recruits the core tip-growth machinery, including ROP signalling proteins. This work provides insights into the orchestration of efficient pollen tube growth and species-specific pollen tube attraction by multiple receptors during male-female communication.
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.|JST ERATO Higashiyama Live-Holonics Project, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Takeuchi
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.|JST ERATO Higashiyama Live-Holonics Project, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.|3Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Higashiyama
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029687:Capsella / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D019204:GTP-Binding Proteins / Q000378:metabolism; D009154:Mutation; D056771:Ovule / Q000378:metabolism; D010641:Phenotype; D010770:Phosphotransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053205:Pollen Tube / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012098:Reproduction; D015398:Signal Transduction; D013045:Species Specificity
chemical_list: D029681:Arabidopsis Proteins; D011956:Receptors, Cell Surface; D010770:Phosphotransferases; C000606286:PRK1 protein, Arabidopsis; C000606279:PRK3 protein, Arabidopsis; C000606285:PRK6 protein, Arabidopsis; C000606287:PRK8 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D019204:GTP-Binding Proteins; C501663:ROP1 protein, Arabidopsis