ABSTRACT
BACKGROUND: Papaya, a nutritious tropical fruit, is consumed both in its fresh form and as a processed product worldwide. Major quality indices which include firmness, acidity, pH, colour and size, are cultivar dependent. Transgenic papayas engineered for resistance to Papaya ringspot virus were evaluated over the ripening period to address physicochemical quality attributes and food safety concerns. RESULTS: With the exception of one transgenic line, no significant differences (P > 0.05) were observed in firmness, acidity and pH. Lightness (L*) and redness (a*) of the pulps of non-transgenic and transgenic papaya were similar but varied over the ripening period (P < 0.05). Fruit mass, though non-uniform (P < 0.05) for some lines, was within the range reported for similar papaya cultivars, as were shape indices of female fruits. Transgene proteins, CP and NPTII, were not detected in fruit pulp at the table-ready stage. CONCLUSION: The findings suggest that transformation did not produce any major unintended alterations in the physicochemical attributes of the transgenic papayas. Transgene proteins in the edible fruit pulp were low or undetectable.
Subject(s)
Carica/chemistry , Crops, Agricultural/chemistry , Food Quality , Food, Genetically Modified , Fruit/chemistry , Functional Food/analysis , Plant Leaves/chemistry , Capsid Proteins/analysis , Capsid Proteins/genetics , Capsid Proteins/metabolism , Carica/genetics , Carica/growth & development , Carica/virology , Chemical Phenomena , Crops, Agricultural/genetics , Crops, Agricultural/growth & development , Crops, Agricultural/virology , Disease Resistance , Food, Genetically Modified/virology , Fruit/genetics , Fruit/growth & development , Fruit/virology , Functional Food/virology , Glucuronidase/analysis , Glucuronidase/genetics , Glucuronidase/metabolism , Jamaica , Kanamycin Kinase/analysis , Kanamycin Kinase/genetics , Kanamycin Kinase/metabolism , Limit of Detection , Plant Diseases/prevention & control , Plant Diseases/virology , Plant Leaves/genetics , Plant Leaves/growth & development , Plant Leaves/virology , Plants, Genetically Modified/chemistry , Plants, Genetically Modified/genetics , Plants, Genetically Modified/growth & development , Plants, Genetically Modified/virology , Potyvirus/enzymology , Potyvirus/metabolism , Recombinant Proteins/analysis , Recombinant Proteins/metabolism , Species Specificity , Viral Proteins/analysis , Viral Proteins/genetics , Viral Proteins/metabolismABSTRACT
Transformation of agricultural crops with novel genes has significantly advanced disease-resistance breeding, including virus resistance through the expression of virus sequences. In this study, the effects of long-term, repeated exposure to transgenic papayas carrying the coat protein gene of Papaya ringspot virus and conventional non-transgenic papaya on the histology and selected biochemical parameters of the intestinal tract were compared. For 3 months, male and female Wistar rats received diets containing transgenic or non-transgenic papaya at twice the equivalent of the average daily consumption of fresh papayas. Gross and macroscopic appearance of intestinal tissues, as well as stomach tissues, was comparable (P < 0.05) as were total intestinal bacterial counts and activities of beta-glucuronidase. Activities of disaccharidases were not affected, neither were those of amylase (P < 0.05). Although significant differences were noted in the activity of Ca(2+) and Na(+)/K(+) ATPase brush border enzymes, no morphological alteration in the integrity of the intestinal mucosa was found. Overall, negligible effects on feed intake, body weight, and fecal output were observed (P < 0.05). Taken together, long-term exposure to diets formulated with transgenic papaya did not result in biologically important unintended effects.
