Pollen Germination and Tube Growth

Taylor, Loverine P.; Hepler, Peter K.

doi:10.1146/annurev.arplant.48.1.461

Cited by 726 publications

(606 citation statements)

References 185 publications

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“…It is well known that Ca 2+ is an important factor in the regulation of pollen tube growth (Feijó et al, 1995;Taylor and Hepler, 1997;Franklin-Tong, 1999). To test whether CPK11 and CPK24 are involved in the Ca 2+ signaling response during pollen tube growth, in vitro pollen tube growth assays were performed with different external Ca 2+ concentrations.…”

Section: Cpk11 and Cpk24 Regulate Pollen Tube Elongationmentioning

confidence: 99%

“…Inorganic ion dynamics play important roles in regulating the rate and direction of pollen tube growth (Holdaway-Clarke and Hepler, 2003;Michard et al, 2009). Four major ions, Ca 2+ , H + , K + , and Cl 2 , are involved in the regulation of pollen tube growth (Feijó et al, 1995;Taylor and Hepler, 1997). Among these ions, Ca 2+ plays a pivotal role.…”

Section: Introductionmentioning

confidence: 99%

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Ca2+-Dependent Protein Kinase11 and 24 Modulate the Activity of the Inward Rectifying K+ Channels inArabidopsisPollen Tubes

et al. 2013

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Potassium (K+) influx into pollen tubes via K+ transporters is essential for pollen tube growth; however, the mechanism by which K+ transporters are regulated in pollen tubes remains unknown. Here, we report that Arabidopsis thaliana Ca2+-dependent protein kinase11 (CPK11) and CPK24 are involved in Ca2+-dependent regulation of the inward K+ (K+ in) channels in pollen tubes. Using patch-clamp analysis, we demonstrated that K+ in currents of pollen tube protoplasts were inhibited by elevated [Ca2+]cyt. However, disruption of CPK11 or CPK24 completely impaired the Ca2+-dependent inhibition of K+ in currents and enhanced pollen tube growth. Moreover, the cpk11 cpk24 double mutant exhibited similar phenotypes as the corresponding single mutants, suggesting that these two CDPKs function in the same signaling pathway. Bimolecular fluorescence complementation and coimmunoprecipitation experiments showed that CPK11 could interact with CPK24 in vivo. Furthermore, CPK11 phosphorylated the N terminus of CPK24 in vitro, suggesting that these two CDPKs work together as part of a kinase cascade. Electrophysiological assays demonstrated that the Shaker pollen K+ in channel is the main contributor to pollen tube K+ in currents and acts as the downstream target of the CPK11-CPK24 pathway. We conclude that CPK11 and CPK24 together mediate the Ca2+-dependent inhibition of K+ in channels and participate in the regulation of pollen tube growth in Arabidopsis.

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Section: Cpk11 and Cpk24 Regulate Pollen Tube Elongationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ca2+-Dependent Protein Kinase11 and 24 Modulate the Activity of the Inward Rectifying K+ Channels inArabidopsisPollen Tubes

et al. 2013

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“…In tomato seeds, endo-␤-mannanase is localized exclusively at the endosperm cap (where the radicle emerges), and its activity degrades cell wall mannans, weakening the surrounding tissue and eventually permitting radicle protrusion (Groot et al, 1988). The pollen tube wall (intine) is bipartite: The inner sheath of callose is covered by an outer fibrillar layer composed of pectin with hemicellulose and cellulose (Taylor and Hepler, 1997). It is plausible that weakening of cell walls is also required in pollen, especially at an aperture, the site of pollen tube emergence.…”

Section: Filichkin Et Almentioning

confidence: 99%

A Novel Endo-β-Mannanase Gene in Tomato LeMAN5 Is Associated with Anther and Pollen Development

et al. 2004

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Endo-β-mannanase (EC 3.2.1.78) is involved in cell wall disassembly and the weakening of plant tissues by degrading mannan polymers in the cell walls. Endo-β-mannanase genes are expressed in tomato (Lycopersicon esculentum) seeds (LeMAN1 and LeMAN2) and fruits (LeMAN3 and LeMAN4). A novel endo-β-mannanase gene (termed LeMAN5) was found in the tomato genome by genome-walking PCR and bacterial artificial chromosome library screening. The 5′-upstream region of this endo-β-mannanase gene contained four copies of the pollen-specific cis-acting elements POLLEN1LELAT52 (AGAAA). A GUS-reporter gene driven with the putative LeMAN5 promoter (-543 to +38) was activated in anthers and pollen of transgenic Arabidopsis, with the highest β-glucuronidase activity detected in pollen. β-Glucuronidase expression was detected in mature pollen retained in sporangia, discharged pollen, and elongating pollen tubes in transgenic Arabidopsis. Consistently, expression of LeMAN5 mRNA and endo-β-mannnanase activity was detected in tomato anthers and pollen. In anthers, the highest mRNA expression and endo-β-mannanase activity were detected during late stages of anther development, when pollen maturation occurred. Endo-β-mannanase activity was present in discharged pollen, which was easily eluted in a buffer, indicating that the enzyme proteins are probably secreted from, and deposited on, the surface of pollen. These data suggest that the LeMAN5 endo-β-mannanase is associated with anther and pollen development.

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“…Recent evidence suggests that, in the pistil, the arabinogalactan protein TTS (Cheung et al, 1995;Wu et al, 2000), lipid-transfer protein , and stylar pectin might serve as extracellular signaling cues. Although pollen tube growth occurs normally in the female tissue, pollen of many species also can germinate and grow pollen tubes when placed in a simple medium (Taylor and Hepler, 1997). This in vitro growth suggests that signaling molecules that regulate tube growth also might be produced by pollen itself.…”

Section: Introductionmentioning

confidence: 99%

A Cysteine-Rich Extracellular Protein, LAT52, Interacts with the Extracellular Domain of the Pollen Receptor Kinase LePRK2[W]

et al. 2002

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Pollen germination and pollen tube growth are thought to require extracellular cues, but how these cues are perceived and transduced remains largely unknown. Pollen receptor kinases are plausible candidates for this role; they might bind extracellular ligands and thereby mediate cytoplasmic events required for pollen germination and pollen tube growth. To search for pollen-expressed ligands for pollen receptor kinases, we used the extracellular domains of three pollen-specific receptor kinases of tomato (LePRK1, LePRK2, and LePRK3) as baits in a yeast two-hybrid screen. We identified numerous secreted or plasma membrane-bound candidate ligands. One of these, the Cys-rich protein LAT52, was known to be essential during pollen hydration and pollen tube growth. We used in vivo coimmunoprecipitation to demonstrate that LAT52 was capable of forming a complex with LePRK2 in pollen and to show that the extracellular domain of LePRK2 was sufficient for the interaction. Soluble LAT52 can exist in differently sized forms, but only the larger form can interact with LePRK2. We propose that LAT52 might be a ligand for LePRK2.

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Pollen Germination and Tube Growth

Cited by 726 publications

References 185 publications

Ca2+-Dependent Protein Kinase11 and 24 Modulate the Activity of the Inward Rectifying K+ Channels inArabidopsisPollen Tubes

Ca2+-Dependent Protein Kinase11 and 24 Modulate the Activity of the Inward Rectifying K+ Channels inArabidopsisPollen Tubes

A Novel Endo-β-Mannanase Gene in Tomato LeMAN5 Is Associated with Anther and Pollen Development

A Cysteine-Rich Extracellular Protein, LAT52, Interacts with the Extracellular Domain of the Pollen Receptor Kinase LePRK2[W]

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