Strategies for Generating Marker-Free Transgenic Plants

An Efficient Gene Excision System in Maize

“…This has been referred to as “auto-excision” ( Verweire et al., 2007 ; Moravčíková et al., 2008 ), and allows generation of SMG-free events. Placing the recombinase under the regulation of an inducible/chemical promoter, an expression system that allowed spatial and temporal control (regulated by external or intrinsic signals) was shown to be faster and less resource-intensive ( Chong-Pérez and Angenon, 2013 ; Yau and Stewart, 2013 ).…”

Alternatives to Antibiotic Resistance Marker Genes forIn VitroSelection of Genetically Modified Plants – Scientific Developments, Current Use, Operational Access and Biosafety Considerations

“…Transforming without SMGs would be the ideal way to obtain marker-free GM plants. The successful recovery of GM plants without the use of SMGs has been reported for several plant species including Arabidopsis, potato, tobacco, lime, peanut, triticale, cassava, barley (reviewed by Manimaran et al, 2011;Schaart et al, 2011;Chong-Pérez and Angenon, 2013), alfalfa (Ferradini et al, 2011b), apple (Malnoy et al, 2010), orange (Ballester et al, 2010), Prunus (Petri et al, 2011), wheat (Liu et al, 2011) and tomato (Xin and Guo, 2012). In most cases putative transformed plants were screened by Polymerase Chain Reaction (PCR) for the presence of the transgene.…”

“…Different approaches for removing SMGs (including ARMG) from the nuclear genome to develop marker-free GM plants are available. They have been reviewed by several authors (Yoder and Goldsbrough, 1994;Hohn et al, 2001;Scutt et al, 2002;Hare and Chua, 2002;Puchta, 2003;Miki and McHugh, 2004;Goldstein et al, 2005;Afolabi, 2007;Darbani et al, 2007;Upadhyaya et al, 2010;Manimaran et al, 2011;Woo et al, 2011;Tuteja et al, 2012;Chong-Pérez and Angenon, 2013;Rukavtsova et al, 2013;Yau and Stewart, 2013). In the following sections, these approaches are presented with up-todate information and discussed with regards to their biosafety implications.…”

Genetic engineering of crops: a ray of hope for enhanced food security

“…Production of marker-free transgenic crops to avoid the risk of horizontal gene transfer, e.g., antibiotic resistance genes from genetically engineered crops to soil-and plant-related microorganisms or escape of herbicide resistant genes to wild relatives also needs the attention of plant scientists. 20,21 Furthermore, stress-inducible promoters, which only express when exposed to stresses, have also been identified with minimum negative effects on the plant growth. Genetic engineering of plants for abiotic stress tolerance with stressinducible promoters has uncovered the way ahead for abiotic stress tolerance without yield penalty.…”