Endo-beta-mannanase activity increases in the skin and outer pericarp of tomato fruits during ripening

Bewley, J. Derek; Banik, Mitali; Bourgault, Richard; Feurtado, J. Allan; Toorop, Peter E.; Hilhorst, Henk W. M.

doi:10.1093/jexbot/51.344.529

Cited by 56 publications

(53 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The fruits of several non-ripening mutants of tomato do not exhibit endo-␤-mannanase activity during ripening, whereas their corresponding wild-type cultivars produce active enzyme (Bewley et al, 2000). Immunoblot analysis (Fig.…”

Section: Immunoblot Analysis Of Non-ripening Mutants Of Tomatomentioning

confidence: 99%

“…Of these three types of mannans, the cell walls of tomato are known to contain glucomannans (Tong and Gross, 1988;Seymour et al, 1990). Endo-␤-mannanase is capable of hydrolyzing these polysaccharides, and the activity of this enzyme increases in the outer tissues of tomato fruits during ripening (Bewley et al, 2000). The enzyme is also active in ripe fruits of a number of other species such as watermelon (Citrullis vulgaris), cantaloupe (Cucumis melo), and peach and nectarine (Prunus persica) .…”

mentioning

confidence: 99%

“…It has been suggested that endo-␤-mannanase plays a role in ripening-associated softening (Pressey, 1989;Bewley et al, 2000), a hypothesis supported to some degree by the fact that the fruits of several non-ripening tomato mutants that fail to soften exhibit very low or no enzyme activity. However, fruit of the tomato cv Walter, which exhibit no endo-␤-mannanase activity during ripening, appear to ripen normally, with only a minor difference in texture in fully ripened fruit (Bewley et al, 2000).The gene for endo-␤-mannanase is present in tomato cv Walter, it is transcribed in the fruit, the message is translated, and the resultant full-length protein is localized in the cell wall, as in cultivars producing active enzyme (Banik et al, 2001). There are no previous reports of permanently inactive hydrolases being produced in plant tissues; the fact that this occurs in tomato cv Walter fruit is intriguing.…”

mentioning

confidence: 99%

“…The enzyme is also active in ripe fruits of a number of other species such as watermelon (Citrullis vulgaris), cantaloupe (Cucumis melo), and peach and nectarine (Prunus persica) . It has been suggested that endo-␤-mannanase plays a role in ripening-associated softening (Pressey, 1989;Bewley et al, 2000), a hypothesis supported to some degree by the fact that the fruits of several non-ripening tomato mutants that fail to soften exhibit very low or no enzyme activity. However, fruit of the tomato cv Walter, which exhibit no endo-␤-mannanase activity during ripening, appear to ripen normally, with only a minor difference in texture in fully ripened fruit (Bewley et al, 2000).…”

mentioning

confidence: 99%

See 3 more Smart Citations

Variation in Its C-Terminal Amino Acids Determines Whether Endo-β-Mannanase Is Active or Inactive in Ripening Tomato Fruits of Different Cultivars

Bourgault

Bewley

2002

Plant Physiology

View full text Add to dashboard Cite

Endo-␤-mannanase cDNAs were cloned and characterized from ripening tomato (Lycopersicon esculentum Mill. cv Trust) fruit, which produces an active enzyme, and from the tomato cv Walter, which produces an inactive enzyme. There is a two-nucleotide deletion in the gene from tomato cv Walter, which results in a frame shift and the deletion of four amino acids at the C terminus of the full-length protein. Other cultivars that produce either active or inactive enzyme show the same absence or presence of the two-nucleotide deletion. The endo-␤-mannanase enzyme protein was purified and characterized from ripe fruit to ensure that cDNA codes for the enzyme from fruit. Immunoblot analysis demonstrated that non-ripening mutants, which also fail to exhibit endo-␤-mannanase activity, do so because they fail to express the protein.In a two-way genetic cross between tomato cvs Walter and Trust, all F 1 progeny from both crosses produced fruit with active enzyme, suggesting that this form is dominant and homozygous in tomato cv Trust. Self-pollination of a plant from the heterozygous F 1 generation yielded F 2 plants that bear fruit with and without active enzyme at a ratio appropriate to Mendelian genetic segregation of alleles. Heterologous expression of the two endo-␤-mannanase genes in Escherichia coli resulted in active enzyme being produced from cultures containing the tomato cv Trust gene and inactive enzyme being produced from those containing the tomato cv Walter gene. Site-directed mutagenesis was used to establish key elements in the C terminus of the endo-␤-mannanase protein that are essential for full enzyme activity.In addition to helping produce a fruit suitable for consumption, ripening-associated softening in tomato (Lycopersicon esculentum Mill.) fruit leads to an increased susceptibility to physical damage during harvest and/or pathogen attack during shipping and storage. This results in crop losses that are costly to producers and consumers alike. Hence, there has been a great deal of research conducted to elucidate the mechanisms involved in ripening-associated softening. Softening in fleshy fruits is caused by the dissolution of pectin in the middle lamella, which reduces cell adhesion (Wakabayashi, 2000), and also by the breakdown of the cell walls themselves. Cell wall breakdown is caused by the concerted action of a number of proteins/enzymes including, but not limited to, expansins, which dissociate the xyloglucan/cellulose network (Brummell et al., 1999); pectin methylesterase, which cleaves methylester groups from pectic polysaccharides; polygalacturonase, which hydrolyzes pectin; and ␤-galactosidase, which removes the galactan side-chains from rhamnogalacturonan I (Brummell and Harpster, 2001).Glucomannans, galactoglucomannans, and galactomannans are polysaccharides present in type I cell walls, which are thought to cross-link cellulose microfibrils in the same manner as xyloglucans, although to a lesser degree (Carpita and Gibeaut, 1993). Of these three types of mannans, the cell walls of tomato a...

show abstract

Section: Immunoblot Analysis Of Non-ripening Mutants Of Tomatomentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Variation in Its C-Terminal Amino Acids Determines Whether Endo-β-Mannanase Is Active or Inactive in Ripening Tomato Fruits of Different Cultivars

Bourgault

Bewley

2002

Plant Physiology

View full text Add to dashboard Cite

show abstract

“…3.2.1.37), which are responsible of the hydrolysis of main chain, the former attacking the internal main-chain linkages and the latter releasing xylosyl residues by endwise attack of xylooligosaccharides (54). Related to this, it has been found that the general enzymatic activity on the fruit grows significantly during certain phases of the ripening period (9).…”

Section: Introductionmentioning

confidence: 97%