Genetic characterization and biosafety assessment of transgenic Oncidesa Gower Ramsey “Honey Snow”

Taiwan has a reputation in the agricultural modification for Oncidesa, of the orchid Kingdom, which is mainly for export as cut flowers. One of the major crisis faced by marketing Oncidesa is its dull appearance of florets and it has remained unchanged for a very long time in any aspect of colors. Currently, the Oncidesa cut flower market is facing a new demand for a new spectrum of colors. With the aid of our previous study, we have devloped a white floret Oncidesa through RNA interference technology. However, one of the major concern deemed by the government of Taiwan is that it required a genetic characterization and environmental biosafety assessment on surrounding biosphere for any genetically modificated organisms (GMOs). Therefore in this study, our plant materials were all grown in a special netted house. Additionally, we were able to characterize this transgenic white Oncidesa and define its transgenic RNAi allele (OgPSY) through genetic characterization. Furthermore, we showed that its phenotype could be sustained within two repetitive vegetative regenerations and that the transformants showed no sign of detrimental and environmental impact to the biosphere as compared with its non-transformant counterparts. Moreover, we investigated the effects of light and temperature on the transgenic Pchrc activity and found that these two environmental factors affected the potency of OgPSY RNAi, resulting in floret color variation on independent generation line of transgenic Oncidesa. Thus, this study holds valuable information in the aspect of the viability of sustaining a stable transgenic line and successfully introducing transgenic Oncidesa in the biosphere.