Differential Accumulation of the Molecular Forms of Polygalacturonase in Tomato Mutants

Brady, Colin J.; Meldrum, S.K.; McGlasson, W. B.; Ali, Zuraidah

doi:10.1111/j.1745-4514.1983.tb00079.x

Cited by 53 publications

(38 citation statements)

References 10 publications

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“…It has been implicated as the primary agent of polyuronide degradation in ripening tomato fruit (Themmen et al, 1982;Huber, 1983) and hence implicated as the primary enzyme regulating tomato fruit softening (Brady et al, 1983).…”

Section: Polygalacturonasementioning

confidence: 99%

Biochemistry of fruit softening: an overview

Payasi¹,

Mishra

Chaves

et al. 2009

Physiol Mol Biol Plants

200

125

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Softening is a developmentally programmed ripening process, associated with biochemical changes in cell wall fractions involving hydrolytic processes resulting in breakdown of cell-wall polymers such as cellulose, hemicelluloses and pectin etc. Various hydrolytic reactions are brought about by polygalacturonase, pectin methyl esterase, pectate lyase, rhamnogalacturonase, cellulase and β-galactosidase etc. Besides these enzymes, expansin protein also plays an important role in softening. Textural changes during ripening help in determining the shelf life of a fruit. An understanding of these changes would help in formulating procedures for controlling fruit softening vis-à-vis enhancing shelf life of fruits. In the present review an attempt has been made to coalesce recent findings on biochemistry of fruit softening.

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Section: Polygalacturonasementioning

confidence: 99%

Biochemistry of fruit softening: an overview

Payasi¹,

Mishra

Chaves

et al. 2009

Physiol Mol Biol Plants

200

125

View full text Add to dashboard Cite

show abstract

“…In ripening tomato fruit, PG1 accumulates before PG2 (Tucker et al, 1980;Brady et al, 1983). Pectin degradation commences with the appearance of PG1, and continues after the accumulation of PG2 has begun (Pressey, 1986).…”

Section: Plant Transformation and Growthmentioning

confidence: 99%

Analysis of tomato polygalacturonase expression in transgenic tobacco.

et al. 1990

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Tomato polygalacturonase is a cell wall enzyme secreted in large amounts during tomato fruit ripening. Polygalacturonase is synthesized as a glycoprotein precursor that undergoes numerous cotranslational and post-translational processing steps during its maturation, yielding three isozymes in tomato fruit, PG1, PGPA, and PGPB. To investigate the physiological roles of the three isozymes and the functional significance of the polygalacturonase processing domains in its intracellular transport and activity, we have examined polygalacturonase expression in transgenic tobacco plants. A full-length polygalacturonase cDNA was placed under control of the cauliflower mosaic virus 35s promoter and introduced into tobacco by way of Agrobacterium-mediated transformation. Analysis of transgenic tobacco plants indicated that (1) immunologically detectable polygalacturonase can be extracted from leaves, roots, and stems of transgenic tobacco plants; ( 2 ) only PGSA and PGPB were detectable in transgenic tobacco; (3) the polygalacturonase isozymes present in transgenic tobacco were electrophoretically indistinguishable from the tomato isozymes; (4) the N-terminal sequence, degree of N-linked glycosylation, and extent of oligosaccharide processing were similar in polygalacturonase from transgenic tobacco and tomato; (5) polygalacturonase was properly localized in cell walls of transgenic tissue; (6) the protein was enzymically active in vitro; however, (7) accumulation of PGPA and PGSB in cell walls of transgenic tobacco did not result in pectin degradation in vivo. These results indicated that tomato polygalacturonase was properly processed and transported to the cell wall of tobacco. However, accumulation of the two polygalacturonase isozymes expressed in this heterologous host was insufficient to promote polyuronide degradation in tobacco leaf tissue.

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“…The effect of nor on the ripening process (Brady et aL, 1982) is probably responsible for the effect of the gene on the softness in SF1 and SF9 measurements. It is known that the ripening process commences a few days before the "turning" stage (Davies and Hobson, 1981), at which the fruits for the experiment were harvested.…”

Section: Multiplicative and Random Interactionmentioning

confidence: 99%

“…genes, affect some or all components of the ripening process. These mutants also affect the softening of the tomato fruit during ripening (Brady et a!., 1982) and their use in breeding programs for extending shelf life, has been considered (Kopeliovich et a!., 1979).…”

Section: Introductionmentioning

confidence: 99%

A mixed model for the effects of single gene, polygenes and their interaction on quantitative traits. 2. The effects of the nor gene and polygenes on tomato fruit softness

1990

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The effects of the nor gene, polygenes and their interaction on tomato fruit softness one (SF1) and nine (SF9) days after picking at "breaker" stage of ripening were studied using two experimental populations, each obtained from a different cross and comprised of F3 families derived from selfed heterozygous (nor/+) F2 plants. The results were analysed using a mixed model for a single gene, polygenes and their interaction. A multiplicative nor x polygenes interaction was detected for SF1, and it was included in the model by log transformation. The multiplicative coefficients of the nor effect on family means were 0-76, 1-07, 1-23, and 0-77, 106, 122 for nor/nor, nor/+, +1+, respectively, in population 1 and 2, each. "Net Polygenic Heritability" was estimated as 051 and 027 in two different populations. The corresponding multiplicative coefficients for SF9 were 0-62, 106 and 151 and 0-60, 107 and 156. After log transformation, a random nor X polygenes interaction was also found for SF9. It was concluded that a rather small experiment of the design used (13-21 families, 305-461 individuals) facilitated simultaneous detection of the effects of a single gene, polygenes and their interaction on quantitative traits, as well as characterization of the nature of the interaction. This provided better understanding of the genetic control, as well as improved estimates of genetic parameters than those obtained when lack of such interaction was assumed.

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Differential Accumulation of the Molecular Forms of Polygalacturonase in Tomato Mutants

Cited by 53 publications

References 10 publications

Biochemistry of fruit softening: an overview

Biochemistry of fruit softening: an overview

Analysis of tomato polygalacturonase expression in transgenic tobacco.

A mixed model for the effects of single gene, polygenes and their interaction on quantitative traits. 2. The effects of the nor gene and polygenes on tomato fruit softness

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