Microarray analyses reveal that plant mutagenesis may induce more transcriptomic changes than transgene insertion

Abstract

Controversy regarding genetically modified (GM) plants and their potential impact on human health contrasts with the tacit acceptance of other plants that were also modified, but not considered as GM products (e.g., varieties raised through conventional breeding such as mutagenesis). What is beyond the phenotype of these improved plants? Should mutagenized plants be treated differently from transgenics? We have evaluated the extent of transcriptome modification occurring during rice improvement through transgenesis versus mutation breeding. We used oligonucleotide microarrays to analyze gene expression in four different pools of four types of rice plants and respective controls: (i) a ␥-irradiated stable mutant, (ii) the M1 generation of a 100-Gy ␥-irradiated plant, (iii) a stable transgenic plant obtained for production of an anticancer antibody, and (iv) the T1 generation of a transgenic plant produced aiming for abiotic stress improvement, and all of the unmodified original genotypes as controls. We found that the improvement of a plant variety through the acquisition of a new desired trait, using either mutagenesis or transgenesis, may cause stress and thus lead to an altered expression of untargeted genes. In all of the cases studied, the observed alteration was more extensive in mutagenized than in transgenic plants. We propose that the safety assessment of improved plant varieties should be carried out on a case-by-case basis and not simply restricted to foods obtained through genetic engineering.food safety evaluation ͉ rice ͉ genetically modified organisms ͉ genetic engineering ͉ ␥-irradiation

Mutagenesis in Plant Breeding for Disease and Pest Resistance

“…The environmental factors lead to changes in physiology and in genome flexibility that can be transferred to next, untreated generations. Batista et al (2008) summarized genes whose expression was altered by microarray analysis into six groups: 1) genes involved in signalling pathways and stress, 2) genes involved in regulatory pathways as second messengers, 3) gene involved in reactive oxygen species (ROS) network; 4) genes implicated in protein modification, 5) genes encoding transcription factors and 6) genes encoding for retrotransposons. They pointed out that similar phenotype does not necessarily mean similar expression profile.…”

Contributions from scientific research to the risk assessment of GMOs. Lessons learned from a symposium held in Brussels, Belgium, 21–22 October 2010

“…They reveal that the acquisition of the traits is accompanied by modifications in transcript levels of untargeted stress-related genes, both in transgenic and mutant lines. Moreover, the number of differentially expressed genes appeared to be larger in mutant lines compared to transgenic lines (Batista et al, 2008).…”

A foresight study on emerging technologies: State of the art of Omics technologies and potential applications in food and feed safety

“…A difficult issue is to interpret these effects in relation to safety of consumers, nutritional quality or impact on environment. In one study (Batista et al 2008), the observed changes in mRNAs could be contributed to induction of stress to the plant. The consequences of this finding and those published by others remain unclear.…”

“…Four studies (Batista et al, 2008;Luo et al, 2009;Montero et al, 2011;Xue et al, 2012) compared transgenic rice to wild type rice.…”