Arabidopsis COBRA‐LIKE 10, a GPI‐anchored protein, mediates directional growth of pollen tubes

• Published in: The Plant journal : for cell and molecular biology 2013-05, Vol.74 (3), p.486-497
• Main Authors: Li, Sha, Ge, Fu‐Rong, Xu, Ming, Zhao, Xin‐Ying, Huang, Guo‐Qiang, Zhou, Liang‐Zi, Wang, Jia‐Gang, Kombrink, Anja, McCormick, Sheila, Zhang, Xian Sheng, Zhang, Yan
• Format: Article
• Language: English
• Subjects: Alleles; Arabidopsis - anatomy & histology; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; asymmetric localization; Cell Membrane - genetics; Cell Membrane - metabolism; cell–cell communication; encodes; Flowers & plants; gene; Glycosylphosphatidylinositols - genetics; Glycosylphosphatidylinositols - metabolism; glycosylphosphatidylinositol‐anchored protein; guidance; Homozygote; Hydrophobic and Hydrophilic Interactions; in-vitro; male gametophyte development; membrane-proteins; Microscopy, Electron, Transmission; Mutagenesis, Insertional; Mutation; oriented cell expansion; Plant Infertility; Plant reproduction; Plant sciences; polar growth; polarized growth; Pollen; Pollen Tube - genetics; Pollen Tube - growth & development; Pollen Tube - ultrastructure; Pollination; Proteins; thaliana; tip growth; wall organization
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/tpj.12139

Summary Successful reproduction of flowering plants requires constant communication between female tissues and growing pollen tubes. Female cells secrete molecules and peptides as nutrients or guidance cues for fast and directional tube growth, which is executed by dynamic changes of intracellular activities within pollen tubes. Compared with the extensive interest in female cues and intracellular activities of pollen tubes, how female cues are sensed and interpreted intracellularly in pollen is poorly understood. We show here that COBL10, a glycosylphosphatidylinositol (GPI)‐anchored protein, is one component of this pollen tube internal machinery. Mutations in COBL10 caused gametophytic male sterility due to reduced pollen tube growth and compromised directional sensing in the female transmitting tract. Deposition of the apical pectin cap and cellulose microfibrils was disrupted in cobl10 pollen tubes. Pollen tube localization of COBL10 at the apical plasma membrane is critical for its function and relies on proper GPI processing and its C‐terminal hydrophobic residues. GPI‐anchored proteins are widespread cell sensors in mammals, especially during egg‐sperm communication. Our results that COBL10 is critical for directional growth of pollen tubes suggest that they play critical roles in cell‐cell communications in plants.