Constitutive overexpression of a ripening-related pepper endo-1,4-beta-glucanase in transgenic tomato fruit does not increase xyloglucan depolymerization or fruit softening.

The ripening-related pepper endo-1,4-beta-D-glucanase (EGase) CaCel1 was over-expressed in transgenic tomato plants under the control of the constitutive 35S promoter to investigate the effects on plant growth and fruit softening of high levels of a potential cell wall-degrading activity. In transgenic fruit, recombinant CaCel1 protein was associated with a high-salt putative cell wall fraction, and extractable CMCase activity was increased by up to 20-fold relative to controls. However, the effects of high levels of EGase activity on fruit cell wall metabolism were relatively small.

Suppression of a ripening-related endo-1,4-beta-glucanase in transgenic pepper fruit does not prevent depolymerization of cell wall polysaccharides during ripening.

The function of the ripening-related endo-1,4-beta-D-glucanase (EGase) CaCel1 in fruit softening was investigated by suppression of CaCel1 gene expression in transgenic pepper (Capsicum annuum L.) plants using constitutive expression of a truncated sense CaCel1 transgene. In suppressed lines, immunodetectable CaCel1 protein and extractable CMCase activity were reduced to at or below the limit of detection in ripe mature red fruit, suggesting that in pepper ripening-related CMCase activity is the product of a single gene.