Pollen Cell Wall Patterns Form from Modulated Phases

AbstractDespite being members of the same species, some strains of wild teosinte maintain themselves as a distinct breeding population by blocking fertilization by pollen from neighboring maize plants. These teosinte strains may be in the process of evolving into a separate species, since reproductive barriers that block gene flow are critical components in speciation. This trait is conferred by the Teosinte crossing barrier1-s (Tcb1-s) haplotype, making Tcb1 a speciation gene candidate. Tcb1-s contains a female gene that blocks non-self-type pollen and a male function that enables self-type pollen to overcome that block. The Tcb1-female gene encodes a Pectin Methylesterase, implying that modification of the pollen cell wall by the pistil is a key mechanism by which these teosinte females reject foreign (but closely related) pollen.One sentence summaryThe Tcb1-female gene encodes a Pectin Methylesterase that in teosinte silks prevents fertilization by maize pollen.

Download Full-text

Pectic arabinan side chains are essential for pollen cell wall integrity during pollen development

Plant Biotechnology Journal ◽

10.1111/pbi.12156 ◽

2014 ◽

Vol 12 (4) ◽

pp. 492-502 ◽

Cited By ~ 16

Author(s):

Katarina Cankar ◽

Anne Kortstee ◽

Marcel A.J. Toonen ◽

Mieke Wolters-Arts ◽

Rudolf Houbein ◽

...

Keyword(s):

Cell Wall ◽

Pollen Development ◽

Cell Wall Integrity ◽

Side Chains ◽

Pollen Cell

Download Full-text

Nodulin Intrinsic Protein 7;1 Is a Tapetal Boric Acid Channel Involved in Pollen Cell Wall Formation

PLANT PHYSIOLOGY ◽

10.1104/pp.18.00604 ◽

2018 ◽

Vol 178 (3) ◽

pp. 1269-1283 ◽

Cited By ~ 7

Author(s):

Pratyush Routray ◽

Tian Li ◽

Arisa Yamasaki ◽

Akira Yoshinari ◽

Junpei Takano ◽

...

Keyword(s):

Cell Wall ◽

Boric Acid ◽

Cell Wall Formation ◽

Intrinsic Protein ◽

Wall Formation ◽

Pollen Cell

Download Full-text

Changes of Enzyme Activity During Pollen Germination in Maize, and Possible Evidence of Lignin Synthesis

Functional Plant Biology ◽

10.1071/pp96015 ◽

1997 ◽

Vol 24 (3) ◽

pp. 329 ◽

Cited By ~ 8

Author(s):

Zin-Huang Liu ◽

Mang-Jye Ger

Keyword(s):

Cell Wall ◽

Enzyme Activity ◽

Pollen Germination ◽

Phenylalanine Ammonia Lyase ◽

Zea Mays L ◽

Iaa Oxidase ◽

Oxidation Activity ◽

Peroxidase Isozymes ◽

Pollen Cell ◽

Germinated Pollen

During pollen germination in Zea mays L., the activity of phenylalanine ammonia-lyase and peroxidases increased, accompanied by a decline of phenolic compounds. Levels of IAA decreased dramatically as the pollen germinated, and this decline was correlated with enhanced IAA oxidation activity by IAA oxidase in the germinated pollen. The cationic peroxidase isozymes (pI 9.0) with estimated molecular mass of 45 kDa may be involved in lignin polymerisation in the pollen cell wall.

Download Full-text

A Complex Journey: Cell Wall Remodeling, Interactions, and Integrity During Pollen Tube Growth

Frontiers in Plant Science ◽

10.3389/fpls.2020.599247 ◽

2020 ◽

Vol 11 ◽

Author(s):

Milagros Cascallares ◽

Nicolás Setzes ◽

Fernanda Marchetti ◽

Gabriel Alejandro López ◽

Ayelén Mariana Distéfano ◽

...

Keyword(s):

Cell Wall ◽

Pollen Tube ◽

Pollen Tube Growth ◽

Molecular Mechanisms ◽

Tube Growth ◽

Polar Growth ◽

Cell Wall Synthesis ◽

Male Gametes ◽

Pollen Cell ◽

Extended Path

In flowering plants, pollen tubes undergo a journey that starts in the stigma and ends in the ovule with the delivery of the sperm cells to achieve double fertilization. The pollen cell wall plays an essential role to accomplish all the steps required for the successful delivery of the male gametes. This extended path involves female tissue recognition, rapid hydration and germination, polar growth, and a tight regulation of cell wall synthesis and modification, as its properties change not only along the pollen tube but also in response to guidance cues inside the pistil. In this review, we focus on the most recent advances in elucidating the molecular mechanisms involved in the regulation of cell wall synthesis and modification during pollen germination, pollen tube growth, and rupture.

Download Full-text

Pollen Patterns Form from Modulated Phases

10.1101/279851 ◽

2018 ◽

Author(s):

Asja Radja ◽

Eric M. Horsley ◽

Maxim O. Lavrentovich ◽

Alison M. Sweeney

Keyword(s):

Phase Separation ◽

Pattern Formation ◽

Physical Process ◽

Biological Evolution ◽

Pollen Grains ◽

Extracellular Polysaccharide ◽

Modulated Phases ◽

Pollen Cell ◽

Modulated Phase ◽

General Physical

AbstractPollen grains are known for their impressive variety of species-specific, microscale surface patterning. Despite having similar biological developmental steps, pollen grain surface features are remarkably geometrically varied. Previous work suggests that a physical process may drive this pattern formation and that the observed diversity of patterns can be explained by viewing pollen pattern development as a phase transition to a spatially modulated phase. Several studies have shown that the polysaccharide material of plant cell walls undergoes phase separation in the absence of cross-linking stabilizers of the mixed phase. Here we show experimental evidence that phase separation of the extracellular polysaccharide material (primexine) during pollen cell development leads to a spatially modulated phase. The spatial pattern of this phase-separated primexine is also mechanically coupled to the undulation of the pollen cell membrane. The resulting patterned pools of denser primexine form the negative template of the ultimate sites of sporopollenin deposition, leading to the final micropattern observed in the mature pollen. We then present a general physical model of pattern formation via modulated phases. Using analytical and numerical techniques, we find that most of the pollen micropatterns observed in biological evolution could result from a physical process of modulated phases. However, an analysis of the relative rates of transitions from states that are equilibrated to or from states that are not equilibrated suggests that while equilibrium states of this process have occurred throughout evolutionary history, there has been no particular evolutionary selection for symmetric, equilibrated states.

Download Full-text

Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

International Astronomical Union Colloquium ◽

10.1017/s0252921100015025 ◽

1997 ◽

Vol 161 ◽

pp. 491-504 ◽

Cited By ~ 3

Author(s):

Frances Westall

Keyword(s):

Cell Wall ◽

Life Forms ◽

Cation Binding ◽

Positive Bacterium ◽

Gram Positive ◽

Gram Positive Bacteria ◽

Transmission Electron ◽

Hydrothermal Sediments ◽

Identification Of Bacteria ◽

The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

Download Full-text