Ultrastructure of the tapetal cell wall in the stamenless-2 mutant of tomato (Lycopersicon esculentum): correlation between structure and male-sterility

PROTOPLASMA ◽  
1995 ◽  
Vol 189 (3-4) ◽  
pp. 249-255 ◽  
Author(s):  
P. L. Polowick ◽  
V. K. Sawhney
Keyword(s):  
Cell Wall ◽  
Lycopersicon Esculentum ◽  
Male Sterility ◽  
Tapetal Cell

The Ultrastructure and Ontogeny of Pollen in Helleborus Foetidus L

1968 ◽  
Vol 3 (2) ◽  
pp. 161-174
Author(s):  
P. ECHLIN ◽  
H. GODWIN
Keyword(s):  
Cell Wall ◽  
Tapetal Cell ◽  
Pollen Grains ◽  
Ultrastructural Level ◽  
Low Molecular Weight ◽  
Cell Organelles ◽  
Helleborus Foetidus ◽  
Ubisch Bodies ◽  
Ubisch Body ◽  
Development Proceeds

The ontogeny of the tapetum and Ubisch bodies in Helleborus foetidus L. has been examined at the ultrastructural level, and their development has been closely linked with that of the sporogenous cell and pollen grains. During development the tapetum passes through successive phases of synthesis, maturity and senescence, ending in complete dissolution. During the anabolic phase of growth, precursors of the Ubisch bodies are formed as spheroidal vesicles of medium electron density within the tapetal cytoplasm; they are associated with a zone of radiating ribosomes, which, as development proceeds, can clearly be seen to be situated on strands of endoplasmic reticulum. The callose special wall round the microspores and the tapetal cell wall now disintegrate and the pro-Ubisch bodies are extruded through the cell membrance of the tapetal cells, where they remain on the surface of the anther cavity and soon become irregularly coated with sporopollenin. Deposition of sporopollenin continues on the Ubisch bodies at the same time as upon the exines of the developing pollen grains. In both cases, the later stages of sporopollenin deposition are associated with electron-transparent layers of unit-membrane dimensions appearing in section as white lines of uniform thickness. Continuing deposition of sporopollenin leads to the formation of compound or aggregate Ubisch bodies. It is conjectured that the sporopollenin is synthesized from the compounds of low molecular weight released into the anther loculus by the breakdown of the callose special wall and the tapetal cell wall. The final stages of tapetal autolysis involve the disappearance of all the cell organelles. An attempt is made to relate the findings to those described in other recent studies on Ubisch body formation and to combine them in a common ontogenetic pattern.

scholarly journals Analysis of the molecular size of tomato (Lycopersicon esculentum Mill) fruit polyuronides by gel filtration and low-speed sedimentation equilibrium

1987 ◽  
Vol 245 (2) ◽  
pp. 463-466 ◽  
Author(s):  
G B Seymour ◽  
S E Harding
Keyword(s):  
Cell Wall ◽  
Lycopersicon Esculentum ◽  
Tomato Fruit ◽  
Gel Filtration ◽  
Molecular Size ◽  
Sedimentation Equilibrium ◽  
Low Speed ◽  
Lycopersicon Esculentum Mill ◽  
Wall Structures ◽  
Molecular Size Distribution

The cell-wall structures of tomato (Lycopersicon esculentum Mill) and other fruit are intimately linked with the nature of their polyuronides. Cell-wall polyuronides from unripe and ripe tomato fruit were isolated and purified and their molecular size and molecular-size distributions were compared. It was demonstrated that there is a considerable decrease in the weight-average Mr upon ripening (from 160,000 +/- 10,000 to 96,000 +/- 4000) and a corresponding increase in polydispersity, particularly at the low-Mr end of the distribution. The estimates of polyuronide molecular size and molecular-size distribution were obtained without the need for polyuronide standards of known Mr by using gel-filtration chromatography combined with the absolute method of low-speed sedimentation equilibrium.

scholarly journals ß-Galactosidase II Activity in Relation to Changes in Cell Wall Galactosyl Composition during Tomato Ripening

1996 ◽  
Vol 121 (1) ◽  
pp. 132-136 ◽  
Author(s):  
C.M. Sean Carrington ◽  
Russell Pressey
Keyword(s):  
Cell Wall ◽  
Lycopersicon Esculentum ◽  
Cell Walls ◽  
Fruit Softening ◽  
Tetraacetic Acid ◽  
Green Fruit ◽  
Last Stage

Activity of ß-galactosidase II (EC 3.2.1.23), which can hydrolyze ß-galactan from tomato cell walls, increased markedly during ripening of `Roma' and `Rutgers' tomatoes (Lycopersicon esculentum Mill.). Activity of two other ß-galactosidase isozymes, incapable of galactan hydrolysis, was present in green fruit and remained unchanged throughout ripening. ß-Galactosidase II activity was not detectable in green fruit of either cultivar, appearing first at the breaker stage of `Roma' fruit and not until the pink stage of `Rutgers' fruit. Consistent with this, galactose loss from Na2CO3-soluble pectin (NSP) was detectable at an earlier stage in `Roma' vs. `Rutgers' fruit. A greater decline in NSP galactose was evident in `Roma' fruit compared to `Rutgers' fruit, in keeping with the higher levels and longer period of ß-galactosidase II expression in the former. Significant galactose loss from trans -1,2-diaminocyclohexane-N,N,N',N' -tetraacetic acid-soluble pectin, in contrast, was not seen until the last stage of ripening. These results indicate that the long-reported, net galactosyl loss from the cell walls of ripening tomatoes correlates with ß-galactosidase II activity. Nonetheless, the observation that softening commenced before ß-galactosidase II activity or galactose loss was detectable suggests some other basis for the earliest stages of ripening-related fruit softening in tomato.

scholarly journals Mobility Limitations of Bound Polygalacturonase in Isolated Cell Wall from Tomato Pericarp Tissue

1990 ◽  
Vol 115 (1) ◽  
pp. 97-101 ◽  
Author(s):  
James W. Rushing ◽  
Donald J. Huber
Keyword(s):  
Cell Wall ◽  
Lycopersicon Esculentum ◽  
Cell Walls ◽  
Active Cell ◽  
Similar Data ◽  
Mobility Limitations ◽  
No Release ◽  
Autolytic Activity ◽  
Isolated Cell

Enzymically active cell wall isolated from mature-green and ripening tomato (Lycopersicon esculentum Mill cv. `Rutgers') fruit was employed to investigate the mobility of the enzyme polygalacturonase (PG, EC 3.2.1.15). Cell walls from mature-green `Rutgers' fruit or from the ripening mutant rin, which alone exhibits little or no release of pectin, were unaffected by the addition of enzymically active cell wall from ripening `Rutgers' fruit, indicating that PG is either not transferred at all or is not transferred to sites of pectin hydrolysis. The quantity of pectin released by the addition of soluble PG to enzymically active wall depended on the quantity of enzyme added. Similar data were obtained using purified PG2. Pectin solubilization from all wall isolates exhibiting enzymically mediated pectin release diminished with time; however, transfer to fresh buffer initiated a resumption of autolytic activity, indicating that an inhibitor is released during the course of pectin hydrolysis.

scholarly journals CELL WALL SYNTHESIS IN `RUTGERS', RIN AND NOR TOMATO FRUIT

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1083e-1083
Author(s):  
Elizabeth J. Mitcham ◽  
Kenneth C. Gross ◽  
Timothy J Ng
Keyword(s):  
Cell Wall ◽  
Lycopersicon Esculentum ◽  
Cell Walls ◽  
Tomato Fruit ◽  
Experimental Period ◽  
Fruit Color ◽  
Transient Increase ◽  
Cell Wall Synthesis ◽  
B Values ◽  
Lycopersicon Esculentum Mill

Cell wall synthesis during development and ripening of `Rutgers', rin and nor tomato (Lycopersicon esculentum Mill.) fruit was quantified by monitoring incorporation of 14C into outer pericarp cell walls after pedicel injection of (U-14C) - sucrose. Fruit color (Hunter “a” and “b” values) and firmness (Instron) were also monitored. 14C-Incorporation continued throughout development and ripening in `Rutgers' cell walls and exhibited a transient increase from late maturegreen to the turning stage. Incorporation of 14C into cell walls of rin pericarp tissue was similar to `Rutgers' at 20 days pest-anthesls (DPA) (immature-green) but decreased to a level similar to red `Rutgers' fruit by 35 DPA. Incorporation of 14C into nor pericarp cell walls was low throughout the experimental period (20 to 75 DPA). In contrast to previous reports, rin and nor pericarp tissue exhibitad a decrease in firmness of the outer pericarp. However, the rate of softening was slower than in `Rutgers'. Pericarp tissue from rin and nor fruit at 70 and 75 DPA, respectively, resisted compression as much as pink `Rutgers' pericarp tissue.

scholarly journals DCET1 Controls Male Sterility Through Callose Regulation, Exine Formation, and Tapetal Programmed Cell Death in Rice

2021 ◽  
Vol 12 ◽  
Author(s):  
Riaz Muhammad Khan ◽  
Ping Yu ◽  
Lianping Sun ◽  
Adil Abbas ◽  
Liaqat Shah ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Male Sterility ◽  
Tapetal Cell ◽  
Pollen Wall ◽  
Rna Recognition Motif ◽  
Male Sterile ◽  
Cell Degeneration ◽  
Regulatory Pathways ◽  
Callose Wall

In angiosperms, anther development comprises of various complex and interrelated biological processes, critically needed for pollen viability. The transitory callose layer serves to separate the meiocytes. It helps in primexine formation, while the timely degradation of tapetal cells is essential for the timely callose wall dissolution and pollen wall formation by providing nutrients for pollen growth. In rice, many genes have been reported and functionally characterized that are involved in callose regulation and pollen wall patterning, including timely programmed cell death (PCD) of the tapetum, but the mechanism of pollen development largely remains ambiguous. We identified and functionally characterized a rice mutant dcet1, having a complete male-sterile phenotype caused by defects in anther callose wall, exine patterning, and tapetal PCD. DCET1 belongs to the RNA recognition motif (RRM)-containing family also called as the ribonucleoprotein (RNP) domain or RNA-binding domain (RBD) protein, having single-nucleotide polymorphism (SNP) substitution from G (threonine-192) to A (isoleucine-192) located at the fifth exon of LOC_Os08g02330, was responsible for the male sterile phenotype in mutant dcet1. Our cytological analysis suggested that DCET1 regulates callose biosynthesis and degradation, pollen exine formation by affecting exine wall patterning, including abnormal nexine, collapsed bacula, and irregular tectum, and timely PCD by delaying the tapetal cell degeneration. As a result, the microspore of dcet1 was swollen and abnormally bursted and even collapsed within the anther locule characterizing complete male sterility. GUS and qRT-PCR analysis indicated that DCET1 is specifically expressed in the anther till the developmental stage 9, consistent with the observed phenotype. The characterization of DCET1 in callose regulation, pollen wall patterning, and tapetal cell PCD strengthens our knowledge for knowing the regulatory pathways involved in rice male reproductive development and has future prospects in hybrid rice breeding.

scholarly journals PRX9 and PRX40 are extensin peroxidases essential for maintaining tapetum and microspore cell wall integrity during Arabidopsis anther development

2018 ◽  
Author(s):  
Joseph R. Jacobowitz ◽  
Jing-Ke Weng
Keyword(s):  
Cell Wall ◽  
Pollen Development ◽  
Tapetal Cell ◽  
Pollen Grains ◽  
Anther Development ◽  
Cell Wall Integrity ◽  
Class Iii ◽  
Male Sterile ◽  
Male Gametes ◽  
Encoding Genes

AbstractPollen and microspore development is an essential step in the life cycle of all land plants that generate male gametes. Within flowering plants, pollen development occurs inside of the anther. Here, we report the identification of two class III peroxidase-encoding genes, PRX9 and PRX40, that are genetically redundant and essential for proper anther and pollen development in Arabidopsis thaliana. Arabidopsis double mutants devoid of functional PRX9 and PRX40 are male-sterile. The mutant anthers display swollen, hypertrophic tapetal cells and pollen grains, suggesting disrupted cell wall integrity. These phenotypes ultimately lead to nearly 100%-penetrant pollen degeneration upon anther maturation. Using immunochemical and biochemical approaches, we show that PRX9 and PRX40 are likely extensin peroxidases that contribute to the establishment of tapetal cell wall integrity during anther development. This work identifies PRX9 and PRX40 as the first extensin peroxidases to be described in Arabidopsis and highlights the importance of extensin cross-linking during plant development.

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