Polypeptide Pattern of Apple Tissues Affected by Calcium-related Physiopathologies

Abstract

Polypeptides from the apple pulp of Smoothee Golden Delicious and White Renete apples were resolved by 1-D denaturing sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). According to the electropherograms, there were lower concentrations of 88, 74, 70.6 and 47.5-42 kDa proteins in bitter pit spots. Proteins weighing 30 and 26 kDa were rare in sound pulp but frequently appeared in pits and adjacent tissue. Finally, a novel 18 kDa protein was found in bitter pit spots in both varieties, and also in chemically induced corky lesions either by magnesium infiltration or ammonium oxalate cortical injections. The available data suggested that the novel protein might be an inhibitor of pectinmethylesterase, a small heat stress protein (smHSP) or a product of the Ypr-10 gene family identified with 'Mal d 1', the main allergen of apples. To elucidate the possible smHSP nature of the 18 kDa, a set of apples were heated at 40 ºC for 20 h, developing this protein in both the oxidised tissue and in the adjacent.

Effect of Pre-Harvest Calcium Sprays on Calcium Concentrations in the Skin and Flesh of Apples

“…Research on bitter pit development of apples is now being focused on other physiological aspects (Val et al, 2006). However, the main attention is still paid to the application of Ca to the fruit, with little success.…”

Low oxygen treatment prior to cold storage decreases the incidence of bitter pit in ‘Golden Reinders’ apples

“…6 Analysis of the polypeptide pattern of BPaffected tissues showed the occurrence of a novel potential protein which might be either an inhibitor of pectin methylesterase, a small heat stress protein (smHSP) or a product of the Ypr-10 gene family identified as 'Mal d 1', the main allergen of apples. 7 Several hypotheses chiefly related to fruit Ca homeostasis problems have been proposed to explain the development of BP injuries, 2,3 which, however, have not yet enabled the implementation of specific strategies to prevent or control its occurrence in practical terms. Recent studies suggest that Ca deficiency may be caused by factors that may alter normal tissue Ca homeostasis (e.g., due to the level of gibberellins and/or abscisic acid, 3,8 or affected by Ca membrane transporters).…”

Is calcium deficiency the real cause of bitter pit? A review

“…Steenkamp et al (1983) observed high oxalate and citrate concentrations in bitter pit areas, and by vacuum infiltration, they identified deterioration of the middle lamella of fruit cells, similar to those observed in naturally occurring pits. From these results, Val et al (2006) used ammonium oxalate cortical injections to trigger likebitter pit symptoms and study the polypeptide pattern in symptomatic and asymptomatic fruits. Finally, they found the novel 18-kDa protein both in natural bitter pit spots and in chemically induced corky lesions.…”