Polygalacturonase in Tomato Fruits and the Induction of Ripening

Brady, CJ; MacAlpine, Gerald A.; McGlasson, W. B.; Veda, Y

doi:10.1071/pp9820171

Cited by 87 publications

(59 citation statements)

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“…As shown in Figure 1, PGl was first detectable after 3 d of propylene treatment in wild-type fruit and after 7 d in rin[E8/PG] fruit, and was then followed by the accumulation of PG2 isozymes after 11 and 30 d of propylene treatment in wild-type and rin[E8/PG] fruit, respectively. This pattern of polygalacturonase isozyme accumulation is similar to that observed previously in wild-type tomato fruit (4,5,30). Accumulation of polygalacturonase in rin[E8/PG] fruit is delayed relative to wild-type fruit but follows a similar pattern, resulting in the appearance of PGl followed by PG2A and PG2B (Fig.…”

Section: Polygalacturonase Isozymessupporting

confidence: 65%

“…Among the ripening-associated enzymes studied in tomato, the cell wall-degrading enzyme polygalacturonase has been analyzed in the greatest detail (2,4,5,8,9,12,13,(24)(25)(26). The site of action of polygalacturonase is the cell wall, where it hydrolyzes polyuronides, or pectins.…”

mentioning

confidence: 99%

“…The increase in the level of chelator-soluble polyuronides during ripening and their corresponding decrease in molecular size have been well documented and are attributed to the action of polygalacturonase (15,22,23). Polygalacturonase activity isolated from ripe fruit is comprised of three closely related isozymes, PGl, PG2A, and PG2B (4,5,10,(18)(19)(20). The PG2 isozymes (PG2A and PG2B) are comprised ofa single catalytic polygalacturonase subunit and differ from one another by degree of glycosylation (10 solubilize pectin from the cell wall and PG2 isozymes responsible for depolymerization of pectic polymers (27).…”

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confidence: 99%

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confidence: 99%

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Polygalacturonase Isozymes and Pectin Depolymerization in Transgenic rin Tomato Fruit

DellaPenna¹,

Lashbrook²,

Toenjes³

et al. 1990

Plant Physiol.

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We have previously described the construction and expression of a chimeric gene that allows developmentally regulated expression of tomato (Lycopersicon esculentum) polygalacturonase in ripening-impaired, mutant (rin) tomato fruit (JJ Giovannoni, D DellaPenna, AB Bennett, The Plant Cell 1: 53-63). We now show that expression of the chimeric polygalacturonase gene in rin tomato fruit resulted in the accumulation of all three polygalacturonase isozymes (PG1, PG2A, and PG2B). Polyuronide solubilization and polyuronide depolymerization both reached their maximal levels in transgenic rin fruit prior to the appearance of PG2 isozymes. These results demonstrate that PG1, PG2A, and PG2B all arise by differential processing of a single gene product and further suggest that the PG1 isozyme is sufficient to carry out both polyuronide solubilization and depolymerization in vivo.Tomato fruit ripening is characterized by a number of coordinated biochemical and physiological changes, which collectively alter fruit color, flavor, and texture. Biochemical and genetic analysis (6, 7) has indicated that many of the physiological processes associated with ripening are regulated at the level of gene expression, a view firmly supported by recent analysis ofgene expression during tomato fruit ripening (1,8,11,14,17,28).Among the ripening-associated enzymes studied in tomato, the cell wall-degrading enzyme polygalacturonase has been analyzed in the greatest detail (2,4,5,8,9,12,13,(24)(25)(26). The site of action of polygalacturonase is the cell wall, where it hydrolyzes polyuronides, or pectins. The increase in the level of chelator-soluble polyuronides during ripening and their corresponding decrease in molecular size have been well documented and are attributed to the action of polygalacturonase (15,22,23). Polygalacturonase activity isolated from ripe fruit is comprised of three closely related isozymes, PGl, PG2A, and PG2B (4,5,10,(18)(19)(20)

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Section: Polygalacturonase Isozymessupporting

confidence: 65%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Polygalacturonase Isozymes and Pectin Depolymerization in Transgenic rin Tomato Fruit

DellaPenna¹,

Lashbrook²,

Toenjes³

et al. 1990

Plant Physiol.

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“…After the BR stage, a ripening-related increase in cell-wall hydrolases has been described (Fischer and Bennett, 1991), including increases in mRNA abundance and activity of PG (Brady et al, 1982;DellaPenna et al, 1986) and EGases (Hall, 1964;Hobson, 1968;Lashbrook et al, 1994). In pericarp the mRNA abundance of both Cell and Cell increases markedly at the BR stage ( Figs.…”

Section: Discussionmentioning

confidence: 99%

Differential Expression of Two Endo-1,4-β-Glucanase Genes in Pericarp and Locules of Wild-Type and Mutant Tomato Fruit

1996

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The mRNA accumulation of two endo-l,4-P-o-glucanase genes, Cell and Cel2, was examined in the pericarp and locules throughout the development of normal tomato (Lycopersicon esculentum) fruit and the ripening-impaired mutants rin and Nr. Both Cell and Cel2 were expressed transiently at the earliest stages of fruit development during a period corresponding to cell division and early cell expansion. In the pericarp, the mRNA abundance of both genes increased markedly at the breaker stage; the leve1 of Cell mRNA decreased later in ripening, and that of Cel2 increased progressively. Cel2 mRNA levels also increased at the breaker stage in locules but after initial locule liquefaction was already complete. In rin fruit mRNA abundance of Cell was reduced and CelZ was virtuaily absent, whereas in Nr Cell was expressed at wild-type levels and Cel2 was reduced. In wild-type fruit ethylene treatment slightly promoted the mRNA accumulation of both genes. In rinfruit ethylene treatment strongly increased the mRNA abundance of Cell to an extent greater than in wild-type fruit, but Cel2 mRNA was absent even after ethylene treatment. These two endo-1 ,~-P -Dglucanase genes, therefore, do not show coordinated expression during fruit development and are subject to distinct regulatory control. These results suggest that the product of the Cel2 gene contributes to ripening-associated cell-wall changes.

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