Effect and safety assessment of the post-harvest physiology change of the genetically modified CMV-resistant tomato
Date Issued
2008
Date
2008
Author(s)
Wu, Chia-Lin
Abstract
Since the commercialization of first transgenic crop in 1996, safety of genetically-modified crops and its related products become major concerns of consumer. Currently, environmental risk assessment brings by transgenic crops and food safety are the two main issues worldwide. To meet global regulatory authorities on the practice of substantial equivalence on transgenic food, which means that food derived from crops produced through biotechnology be as safe as food produced from conventionally bred crops, this study has investigated the variations of the gene expressions and protein accumulations in transgenic tomato fruits throughout the post-harvest and processing processes. We used Southern blotting and real-time PCR to verify single copy of CMV coat protein gene found within the genome of the transgenic tomato lines in this experiment. Comparison of seven ripening-related gene expressions between genetically modified (GM) and non-GM tomato fruits at different ripening stages by real-time quantitative PCR were also carried out. No significant differences were found in seven ripening-related gene expressions among GM and Non-GM tomato fruits at the same ripening stage. Furthermore, the expression of exogenous gene - CMV coat protein showed no significant changes in GM tomato fruit among different ripening stages. Detection of CMV coat protein among different ripening stages of transgenic tomato fruits is done by Western blotting. The CMV coat protein accumulations is extremely low in transgenic tomato fruits. The limitation of colorimetric detection was about 0.1 μg of purified CMV coat protein. We further compared with exogenous gene and ripening-related gene expressions among GM tomato fruits. The CMV coat protein gene transcripts were significantly lower than ripening-related gene transcripts. Therefore, it is presumed that post-transcriptional gene silencing mechanism may be the reason of anti-virus ability in transgenic tomato. Subsequently, two-dimensional electrophoresis was used to analysis the differential accumulations of total proteins among GM and Non-GM tomato fruits. The results indicated that there were some differential accumulations of proteins between GM and Non-GM tomato fruits. However the differential expression of proteins may be due to the environmental changes or experiment manipulation errors. Therefore, further study should focus on the properties of the differential proteins using western blotting or mass spectrometry.
Subjects
cucumber mosaic virus
differential gene expression
genetically modified tomato
post-harvest physiology change
real-time PCR
western blotting
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-97-R95628204-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):90cce2f379957b03fa742bf4e4dfd625