Proteomics Insight into the Biological Safety of Transgenic Modification of Rice As Compared with Conventional Genetic Breeding and Spontaneous Genotypic Variation

The potential of unintended effects caused by transgenic
events is a key issue in the commercialization of genetically modified
(GM) crops. To investigate whether transgenic events cause unintended
effects, we used comparative proteomics approaches to evaluate proteome
differences in seeds from 2 sets of GM indica rice,
herbicide-resistant Bar68-1 carrying bar and insect-resistant
2036-1a carrying cry1Ac/sck, and
their respective controls D68 and MH86, as well as indica variety MH63, a parental line for breeding MH86, and japonica variety ZH10. This experimental design allowed for comparing proteome
difference caused by transgenes, conventional genetic breeding, and
natural genetic variation. Proteomics analysis revealed the maximum
numbers of differentially expressed proteins between indica and japonica cultivars, second among indica varieties with relative small difference between MH86 and MH63,
and the minimum between GM rice and respective control, thus indicating
GM events do not substantially alter proteome profiles as compared
with conventional genetic breeding and natural genetic variation.
Mass spectrometry analysis revealed 234 proteins differentially expressed
in the 6 materials, and these proteins were involved in different
cellular and metabolic processes with a prominent skew toward metabolism
(31.2%), protein synthesis and destination (25.2%), and defense response
(22.4%). In these seed proteomes, proteins implicated in the 3 prominent
biological processes showed significantly different composite expression
patterns and were major factors differentiating japonica and indica cultivars, as well as indica varieties. Thus, metabolism, protein synthesis and destination,
and defense response in seeds are important in differentiating rice
cultivars and varieties.