scholarly journals Exocytosis and Endocytosis: Yin-Yang Crosstalk for Sculpting a Dynamic Growing Pollen Tube Tip

2020 ◽  
Vol 11 ◽  
Author(s):  
Lifeng Zhao ◽  
Muhammad Saad Rehmani ◽  
Hao Wang
Keyword(s):  
Cell Growth ◽  
Pollen Tube ◽  
Cell Polarity ◽  
Pollen Tubes ◽  
Vesicular Trafficking ◽  
The Novel ◽  
Cellular Processes ◽  
Polar Cell ◽  
Model Cell ◽  
Insight Into

The growing pollen tube has become one of the most fascinating model cell systems for investigations into cell polarity and polar cell growth in plants. Rapidly growing pollen tubes achieve tip-focused cell expansion by vigorous anterograde exocytosis, through which various newly synthesized macromolecules are directionally transported and deposited at the cell apex. Meanwhile, active retrograde endocytosis counter balances the exocytosis at the tip which is believed to recycle the excessive exocytic components for multiple rounds of secretion. Therefore, apical exocytosis and endocytosis are the frontline cellular processes which drive the polar growth of pollen tubes, although they represent opposite vesicular trafficking events with distinct underpinning mechanisms. Nevertheless, the molecular basis governing the spatiotemporal crosstalk and counterbalance of exocytosis and endocytosis during pollen tube polarization and growth remains elusive. Here we discuss recent insight into exocytosis and endocytosis in sculpturing high rates of polarized pollen tube growth. In addition, we especially introduce the novel integration of mathematical modeling in uncovering the mysteries of cell polarity and polar cell growth.

scholarly journals Rho GTPase ROP1 Interactome Analysis Reveals Novel ROP1-Associated Pathways for Pollen Tube Polar Growth in Arabidopsis

2020 ◽  
Vol 21 (19) ◽  
pp. 7033
Author(s):  
Hui Li ◽  
Jinbo Hu ◽  
Jing Pang ◽  
Liangtao Zhao ◽  
Bing Yang ◽  
...  
Keyword(s):  
Cell Growth ◽  
Pollen Tube ◽  
Rho Gtpase ◽  
Ion Homeostasis ◽  
Pollen Tubes ◽  
Polar Growth ◽  
Cell Wall Modification ◽  
Polar Cell ◽  
Associated Proteins ◽  
Arabidopsis Pollen

ROP (Rho-like GTPases from plants) GTPases are polarly localized key regulators of polar growth in pollen tubes and other cells in plants. However, how ROP GTPases are regulated and how they control polar growth remains to be fully understood. To gain new insights into ROP-dependent mechanisms underlying polar cell growth, we characterized the interactome of ROP1 GTPase that controls Arabidopsis pollen tube (PT) tip growth, an extreme form of polar cell growth. We established an efficient method for culturing Arabidopsis pollen tubes in liquid medium, which was used for immunoprecipitation/mass spectrometry-based identification of ROP1-associated proteins. A total of 654 candidates were isolated from the ROP1 interactome in Arabidopsis pollen tubes, and GO (Gene Ontology) classification and pathway analysis revealed multiple uncharacterized ROP1-dependent processes including translation, cell wall modification, post transcriptional modification, and ion homeostasis, in addition to known ROP1-dependent pathways. The ROP1-interactome data was further supported by the co-expression of the candidate interactors in highly mature pollen with PT germination and growth defects being discovered in 25% (8/32) of the candidate mutant genes. Taken together, our work uncovers valuable information for the identification and functional elucidation of ROP-associated proteins in the regulation of polar growth, and provides a reliable reference to identify critical regulators of polar cell growth in the future.

scholarly journals Structure of the 14-3-3ζ–LKB1 fusion protein provides insight into a novel ligand-binding mode of 14-3-3

2015 ◽  
Vol 71 (9) ◽  
pp. 1114-1119 ◽  
Author(s):  
Sheng Ding ◽  
Ruiqing Zhou ◽  
Yaqin Zhu
Keyword(s):  
Crystal Structure ◽  
Energy Metabolism ◽  
Cell Growth ◽  
Fusion Protein ◽  
Ligand Binding ◽  
Cell Polarity ◽  
Binding Mode ◽  
Cellular Processes ◽  
Potential Binding ◽  
Insight Into

The 14-3-3 proteins are a family of highly conserved proteins that play key roles in many cellular processes. The tumour suppressor LKB1 regulates cell polarity, cell growth and energy metabolism. 14-3-3 proteins bind to LKB1 and suppress its functions. Previously, preliminary crystallographic data for the 14-3-3ζ–LKB1 fusion protein have been reported. Here, the crystal structure of this fusion protein was solved and a novel potential binding mode of 14-3-3 to its ligands was found.

scholarly journals Nt-RhoGDI2 regulates Rac/Rop signaling and polar cell growth in tobacco pollen tubes

2006 ◽  
Vol 46 (6) ◽  
pp. 1018-1031 ◽  
Author(s):  
Ulrich Klahre ◽  
Claude Becker ◽  
Arno C. Schmitt ◽  
Benedikt Kost
Keyword(s):  
Cell Growth ◽  
Pollen Tubes ◽  
Polar Cell ◽  
Tobacco Pollen

The Monk

2016 ◽  
Author(s):  
Matthew Lewis
Keyword(s):  
French Revolution ◽  
English Literature ◽  
Young Girl ◽  
The Novel ◽  
Reading Public ◽  
Ghost Stories ◽  
Gothic Fiction ◽  
Black Magic ◽  
Insight Into ◽  
Profound Insight

‘He was deaf to the murmurs of conscience, and resolved to satisfy his desires at any price.’ The Monk (1796) is a sensational story of temptation and depravity, a masterpiece of Gothic fiction and the first horror novel in English literature. The respected monk Ambrosio, the Abbot of a Capuchin monastery in Madrid, is overwhelmed with desire for a young girl; once having abandoned his monastic vows he begins a terrible descent into immorality and violence. His appalling fall from grace embraces blasphemy, black magic, torture, rape, and murder, and places his very soul in jeopardy. Lewis’s extraordinary tale drew on folklore, legendary ghost stories, and contemporary dread inspired by the terrors of the French Revolution. Its excesses shocked the reading public and it was condemned as obscene. The novel continues to beguile and shock readers today with its gruesome catalogue of iniquities, while at the same time giving a profound insight into the deep anxieties experienced by British citizens during one of the most turbulent periods in the nation’s history.

scholarly journals Protein Analysis of Pollen Tubes after the Treatments of Membrane Trafficking Inhibitors Gains Insights on Molecular Mechanism Underlying Pollen Tube Polar Growth

2021 ◽  
Vol 40 (2) ◽  
pp. 205-222
Author(s):  
Monica Scali ◽  
Alessandra Moscatelli ◽  
Luca Bini ◽  
Elisabetta Onelli ◽  
Rita Vignani ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Actin Cytoskeleton ◽  
Membrane Trafficking ◽  
Tip Growth ◽  
Male Gametophyte ◽  
Pollen Tubes ◽  
Structural Features ◽  
Two Dimensional Gel Electrophoresis ◽  
Depth Analysis

AbstractPollen tube elongation is characterized by a highly-polarized tip growth process dependent on an efficient vesicular transport system and largely mobilized by actin cytoskeleton. Pollen tubes are an ideal model system to study exocytosis, endocytosis, membrane recycling, and signaling network coordinating cellular processes, structural organization and vesicular trafficking activities required for tip growth. Proteomic analysis was applied to identifyNicotiana tabacumDifferentially Abundant Proteins (DAPs) after in vitro pollen tube treatment with membrane trafficking inhibitors Brefeldin A, Ikarugamycin and Wortmannin. Among roughly 360 proteins separated in two-dimensional gel electrophoresis, a total of 40 spots visibly changing between treated and control samples were identified by MALDI-TOF MS and LC–ESI–MS/MS analysis. The identified proteins were classified according to biological processes, and most proteins were related to pollen tube energy metabolism, including ammino acid synthesis and lipid metabolism, structural features of pollen tube growth as well modification and actin cytoskeleton organization, stress response, and protein degradation. In-depth analysis of proteins corresponding to energy-related pathways revealed the male gametophyte to be a reliable model of energy reservoir and dynamics.

scholarly journals Hyperoside promotes pollen tube growth by regulating the depolymerization effect of actin-depolymerizing factor 1 on microfilaments in okra

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Biying Dong ◽  
Qing Yang ◽  
Zhihua Song ◽  
Lili Niu ◽  
Hongyan Cao ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Actin Depolymerizing Factor ◽  
Specific Mechanism ◽  
Promoting Effect ◽  
New Research

AbstractMature pollen germinates rapidly on the stigma, extending its pollen tube to deliver sperm cells to the ovule for fertilization. The success of this process is an important factor that limits output. The flavonoid content increased significantly during pollen germination and pollen tube growth, which suggests it may play an important role in these processes. However, the specific mechanism of this involvement has been little researched. Our previous research found that hyperoside can prolong the flowering period of Abelmoschus esculentus (okra), but its specific mechanism is still unclear. Therefore, in this study, we focused on the effect of hyperoside in regulating the actin-depolymerizing factor (ADF), which further affects the germination and growth of pollen. We found that hyperoside can prolong the effective pollination period of okra by 2–3-fold and promote the growth of pollen tubes in the style. Then, we used Nicotiana benthamiana cells as a research system and found that hyperoside accelerates the depolymerization of intercellular microfilaments. Hyperoside can promote pollen germination and pollen tube elongation in vitro. Moreover, AeADF1 was identified out of all AeADF genes as being highly expressed in pollen tubes in response to hyperoside. In addition, hyperoside promoted AeADF1-mediated microfilament dissipation according to microfilament severing experiments in vitro. In the pollen tube, the gene expression of AeADF1 was reduced to 1/5 by oligonucleotide transfection. The decrease in the expression level of AeADF1 partially reduced the promoting effect of hyperoside on pollen germination and pollen tube growth. This research provides new research directions for flavonoids in reproductive development.

scholarly journals Testing of self-(in)compatibility in apricot cultivars from European breeding programmes

2013 ◽  
Vol 40 (No. 2) ◽  
pp. 65-71 ◽  
Author(s):  
D. Milatović ◽  
D. Nikolić ◽  
B. Krška
Keyword(s):  
Fluorescence Microscopy ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Reliable Method ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Self Incompatibility ◽  
Breeding Programmes

Self-(in)compatibility was tested in 40 new apricot cultivars from European breeding programmes. Pollen-tube growth in pistils from laboratory pollinations was analysed using the fluorescence microscopy. Cultivars were considered self-compatible if at least one pollen tube reached the ovary in the majority of pistils. Cultivars were considered self- incompatible if the growth of pollen tubes in the style stopped along with formation of characteristic swellings. Of the examined cultivars, 18 were self-compatible and 22 were self-incompatible. Fluorescence microscopy provides a relatively rapid and reliable method to determine self-incompatibility in apricot cultivars.      

scholarly journals Persistent directional growth capability in Arabidopsis thaliana pollen tubes after nuclear elimination from the apex

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kazuki Motomura ◽  
Hidenori Takeuchi ◽  
Michitaka Notaguchi ◽  
Haruna Tsuchi ◽  
Atsushi Takeda ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pollen Tube ◽  
Sperm Cell ◽  
Pollen Tubes ◽  
Vegetative Nucleus ◽  
Sperm Cells ◽  
Apical Region ◽  
Basal Region ◽  
Specific Expression ◽  
Directional Growth

AbstractDuring the double fertilization process, pollen tubes deliver two sperm cells to an ovule containing the female gametes. In the pollen tube, the vegetative nucleus and sperm cells move together to the apical region where the vegetative nucleus is thought to play a crucial role in controlling the direction and growth of the pollen tube. Here, we report the generation of pollen tubes in Arabidopsis thaliana whose vegetative nucleus and sperm cells are isolated and sealed by callose plugs in the basal region due to apical transport defects induced by mutations in the WPP domain-interacting tail-anchored proteins (WITs) and sperm cell-specific expression of a dominant mutant of the CALLOSE SYNTHASE 3 protein. Through pollen-tube guidance assays, we show that the physiologically anuclear mutant pollen tubes maintain the ability to grow and enter ovules. Our findings provide insight into the sperm cell delivery mechanism and illustrate the independence of the tip-localized vegetative nucleus from directional growth control of the pollen tube.

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