Article

New pollen-specific receptor kinases identified in tomato, maize and Arabidopsis: the tomato kinases show overlapping but distinct localization patterns on pollen tubes. Plant Mol Biol

University of California, Berkeley, Berkeley, California, United States
Plant Molecular Biology (Impact Factor: 4.26). 10/2002; 50(1):1-16. DOI: 10.1023/A:1016077014583
Source: PubMed

ABSTRACT

We previously characterized LePRK1 and LePRK2, pollen-specific receptor kinases from tomato (Muschietti et al., 1998). Here we identify a similar receptor kinase from maize, ZmPRK1, that is also specifically expressed late in pollen development, and a third pollen receptor kinase from tomato, LePRK3. LePRK3 is less similar to LePRK1 and LePRK2 than either is to each other. We used immunolocalization to show that all three LePRKs localize to the pollen tube wall, in partially overlapping but distinct patterns. We used RT-PCR and degenerate primers to clone homologues of the tomato kinases from other Solanaceae. We deduced features diagnostic of pollen receptor kinases and used these criteria to identify family members in the Arabidopsis database. RT-PCR confirmed pollen expression for five of these Arabidopsis candidates; two of these are clearly homologues of LePRK3. Our results reveal the existence of a distinct pollen-specific receptor kinase gene family whose members are likely to be involved in perceiving extracellular cues during pollen tube growth.

Download full-text

Full-text

Available from: Sheila McCormick
  • Source
    • "The tetrapeptide FNYF in the conserved C-terminal region of LeSTIG1 is the core domain sufficient for binding to LePRKs. The three pollen tube receptors LePRK1-3 share similar expression patterns in the flower, but they possess different binding affinities with different peptides (Kim et al., 2002). For example during pollen germination LePRK2 binds LAT52, while during pollen tube elongation LePRK1 and LePRK2 bind STIG1. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Flowering seed plants (angiosperms) have evolved unique ways to protect their gametes from pathogen attack and from drying out. The female gametes (egg and central cell) are deeply embedded in the maternal tissues of the ovule inside the ovary, while the male gametes (sperm cells) are enclosed in the vegetative pollen tube cell. After germination of the pollen tube at the surface of papilla cells of the stigma the two immobile sperm cells are transported deep inside the sporophytic maternal tissues to be released inside the ovule for double fertilization. Angiosperms have evolved a number of hurdles along the pollen tube journey to prevent inbreeding and fertilization by alien sperm cells, and to maximize reproductive success. These pre-zygotic hybridization barriers require intensive communication between the male and female reproductive cells and the necessity to distinguish self from non-self interaction partners. General molecules such as nitric oxide (NO) or gamma-aminobutyric acid (GABA) therefore appear to play only a minor role in these species-specific communication events. The past 20 years have shown that highly polymorphic peptides play a leading role in all communication steps along the pollen tube pathway and fertilization. Here we review our current understanding of the role of peptides during reproduction with a focus on peptide signalling during self-incompatibility, pollen tube growth and guidance as well as sperm reception and gamete activation. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.
    Full-text · Article · Jun 2015 · Journal of Experimental Botany
  • Source
    • "The JM and CT domains regulate AtPRK2 function | Page 9 of 12 JM and CT domains of AtPRK2 and its orthologues share little conservation (see Supplementary Fig. S2 at JXB online), unlike their kinase domains (Kim et al., 2002). Only a few conserved residues within the JM domain could be identified by aligning AtPRK2 with its orthologues from different plant species (see Supplementary Fig. S2 at JXB online). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Polarized growth of pollen tubes is a critical step for successful reproduction in angiosperms and is controlled by ROP GTPases. Spatiotemporal activation of ROP (Rho GTPases of plants) necessitates a complex and sophisticated regulatory system, in which guanine nucleotide exchange factors (RopGEFs) are key components. It was previously shown that a leucine-rich repeat receptor-like kinase, Arabidopsis pollen receptor kinase 2 (AtPRK2), interacted with RopGEF12 for its membrane recruitment. However, the mechanisms underlying AtPRK2-mediated ROP activation in vivo are yet to be defined. It is reported here that over-expression of AtPRK2 induced tube bulging that was accompanied by the ectopic localization of ROP-GTP and the ectopic distribution of actin microfilaments. Tube depolarization was also induced by a potentially kinase-dead mutant, AtPRK2K366R, suggesting that the over-expression effect of AtPRK2 did not require its kinase activity. By contrast, deletions of non-catalytic domains in AtPRK2, i.e. the juxtamembrane (JM) and carboxy-terminal (CT) domains, abolished its ability to affect tube polarization. Notably, AtPRK2K366R retained the ability to interact with RopGEF12, whereas AtPRK2 truncations of these non-catalytic domains did not. Lastly, it has been shown that the JM and CT domains of AtPRK2 were not only critical for its interaction with RopGEF12 but also critical for its distribution at the plasma membrane. These results thus provide further insight into pollen receptor kinase-mediated ROP activation during pollen tube growth.
    Full-text · Article · Oct 2013 · Journal of Experimental Botany
  • Source
    • "The JM and CT domains regulate AtPRK2 function | Page 9 of 12 JM and CT domains of AtPRK2 and its orthologues share little conservation (see Supplementary Fig. S2 at JXB online), unlike their kinase domains (Kim et al., 2002). Only a few conserved residues within the JM domain could be identified by aligning AtPRK2 with its orthologues from different plant species (see Supplementary Fig. S2 at JXB online). "

    Full-text · Article · Aug 2013
Show more