Genetic Transformation of Dendrobium 'Sonia Earsakul' with Antisense Carica papaya ACO1 Gene

Dendrobium orchid is one of the major export cut flowers not only in Thailand but also for several tropical countries. However, the production of ethylene by their flowers causes a shorter vase life. Flowers that contained lower levels of ethylene usually exhibited delayed senescence and consequently prolonged vase life. The transfer of antisense ACC oxidase (ACO) gene into orchid, in theory, may leads to decreased ethylene production because this gene can down regulates the ethylene biosynthesis pathway. This study focuses on the transformation and the existence and expression of the antisense ACO1 gene from papaya, namely (CP-ACO1), which was transferred in to Dendrobium 'Sonia Earsakul'. The successful stable transformation event obtained and the existence of the transferred gene was determined using PCR, dot blot hybridization and Southern blot hybridization techniques. The results revealed that antisense CP-ACO1 and hygromycin phosphotransferase (hpt) gene existed in all transgenic lines confirmed by PCR technique. The genomic dot blot confirmed the incorporation of the transgene in transgenic plant genome. Southern blot hybridization revealed the existed of one to four sets of the gene in transgenic lines. The expression of antisense CP-ACO1 gene was analyzed through the level of ACO enzyme activity and ethylene production in transgenic orchid. All of the transgenic lines had lower ACO enzyme activity and lower ethylene production than that of the non-transgenic orchid plants. Â