Central-cell-produced attractants control fertilization recovery.

Animal fertilization relies on hundreds of sperm racing toward the egg, whereas, in angiosperms, only two sperm cells are delivered by a pollen tube to the female gametes (egg cell and central cell) for double fertilization. However, unsuccessful fertilization under this one-pollen-tube design can be detrimental to seed production and plant survival. To mitigate this risk, unfertilized-gamete-controlled extra pollen tube entry has been evolved to bring more sperm cells and salvage fertilization.

Homeostasis of flavonoids and triterpenoids most likely modulates starch metabolism for pollen tube penetration in rice.

In angiosperms, the timely delivery of sperm cell nuclei by pollen tube (PT) to the ovule is vital for double fertilization. Penetration of PT into maternal stigma tissue is a critical step for sperm cell nuclei delivery, yet little is known about the process. Here, a male-specific and sporophytic mutant xt6, where PTs are able to germinate but unable to penetrate the stigma tissue, is reported in Oryza sativa.

Osmoregulation determines sperm cell geometry and integrity for double fertilization in flowering plants.

Distinct from the motile flagellated sperm of animals and early land plants, the non-motile sperm cells of flowering plants are carried in the pollen grain to the female pistil. After pollination, a pair of sperm cells are delivered into the embryo sac by pollen tube growth and rupture. Unlike other walled plant cells with an equilibrium between internal turgor pressure and mechanical constraints of the cell walls, sperm cells wrapped inside the cytoplasm of a pollen vegetative cell have only thin and discontinuous cell walls.

POD1-SUN-CRT3 chaperone complex guards the ER sorting of LRR receptor kinases in Arabidopsis.

Protein sorting in the secretory pathway is essential for cellular compartmentalization and homeostasis in eukaryotic cells. The endoplasmic reticulum (ER) is the biosynthetic and folding factory of secretory cargo proteins. The cargo transport from the ER to the Golgi is highly selective, but the molecular mechanism for the sorting specificity is unclear.

Nucleolar histone deacetylases HDT1, HDT2, and HDT3 regulate plant reproductive development.

Nucleolus is a membrane-less organelle where ribosomes are assembled, and ribosomal RNAs (rRNAs) transcribed and processed. The assembled ribosomes composed of ribosomal proteins and rRNAs synthesize proteins for cell survival. In plants, the loss of nucleolar ribosomal proteins often causes gametophytically or embryonically lethality.

Plasma membrane H -ATPases-mediated cytosolic proton gradient regulates pollen tube growth.

The polar growth of pollen tubes is essential for the delivery of sperm cells during fertilization in angiosperms. How this polar growth is regulated has been a long-standing question. An in vitro pharmacological assay previously implicated proton flux in pollen tube growth, although genetic and cellular supporting evidence was lacking.

Integration of ovular signals and exocytosis of a Ca channel by MLOs in pollen tube guidance.

The spatiotemporal regulation of Ca channels at the plasma membrane in response to extracellular signals is critical for development, stress response and reproduction, but is poorly understood. During flowering-plant reproduction, pollen tubes grow directionally to the ovule, which is guided by ovule-derived signals and dependent on Ca dynamics. However, it is unknown how ovular signals are integrated with cytosolic Ca dynamics in the pollen tube.

LOT regulates TGN biogenesis and Golgi structure in plants.

Trans-Golgi Network (TGN) is an essential organelle in eukaryotic cells. It acts not only as the sorting station of trafficking cargoes, but also as a signaling hub. In plant cells, TGN simultaneously takes the role of early endosome (EE) and contributes to the endocytic recycling.

Golgi-localized LOT regulates -Golgi network biogenesis and pollen tube growth.

The -Golgi network (TGN) is an essential tubular-vesicular organelle derived from the Golgi and functions as an independent sorting and trafficking hub within the cell. However, the molecular regulation of TGN biogenesis remains enigmatic. Here we identified an mutant loss of TGN () that is defective in TGN formation and sterile due to impaired pollen tube growth in the style.

Transmission Electron Microscopy (TEM) to Study Histology of Pollen and Pollen Tubes.

Here, we describe methods of transmission electron microscopy (TEM) based on conventional chemical fixation and high-pressure freezing (HPF) and freeze-substitution (FS) to examine the ultrastructure of Arabidopsis pollen grains and pollen tubes. Compared to other plant samples, such as root or leaf, pollen grains have thick pollen coat and cell wall which limit the permeation of fixative. Thus, it is difficult to obtain high-quality ultrastructural images of pollen.

Analysis of Peroxisome Biogenesis in Pollen by Confocal Microscopy and Transmission Electron Microscopy.

Peroxisome is an essential single-membrane bound organelle in most eukaryotic cells and functions in diverse cellular processes. De novo formation, division, and turnover of peroxisomes contribute to its biogenesis, morphology, and population regulation. In plants, peroxisome plays multiple roles, including metabolism, development, and stress response.

The Arabidopsis Receptor Kinase ZAR1 Is Required for Zygote Asymmetric Division and Its Daughter Cell Fate.

Asymmetric division of zygote is critical for pattern formation during early embryogenesis in plants and animals. It requires integration of the intrinsic and extrinsic cues prior to and/or after fertilization. How these cues are translated into developmental signals is poorly understood.

A receptor heteromer mediates the male perception of female attractants in plants.

Sexual reproduction requires recognition between the male and female gametes. In flowering plants, the immobile sperms are delivered to the ovule-enclosed female gametophyte by guided pollen tube growth. Although the female gametophyte-secreted peptides have been identified to be the chemotactic attractant to the pollen tube, the male receptor(s) is still unknown.

Functional characterization of the CKRC1/TAA1 gene and dissection of hormonal actions in the Arabidopsis root.

Cytokinin (CK) influences many aspects of plant growth and development, and its function often involves intricate interactions with other phytohormones such as auxin and ethylene. However, the molecular mechanisms underlying the role of CK and its interactions with other growth regulators are still poorly understood. Here we describe the isolation and characterization of the Arabidopsis CK-induced root curling 1 (ckrc1) mutant.

Dual-rhodamine urea derivative, a novel chemidosimeter for Hg(II) and its application in imaging Hg(II) in living cells.

The synthesis and spectral properties of a chemidosimeter 1,4-di[2-(6-ethylamino-3-ethylimino-2,7-dimethyl-3H-xanthen-9-yl) benzoic acid (aminomethyl)-3-phenylthiourea] benzene (1) for Hg(II) ions are reported, and it has been demonstrated that 1 can be used as a fluorescent probe for monitoring Hg(II) ions in living cells.

Novel mode of action of polybia-MPI, a novel antimicrobial peptide, in multi-drug resistant leukemic cells.

As the frequent emergency of resistant tumor cells during treatment, the development of new agents with new modes of action attracts a great deal of interest. Polybia-MPI was a short cationic alpha-helical amphiphilic peptide that has selective toxicity toward cancer cells but no hemolytic activity. Its target selectivity is based on the binding preference to membranes containing anionic phospholipids by electrostatic driving.