Oncidium is a popular ornamental orchid and is
produced as a high value cash crop for cut flower sold
worldwide. Genetically transformed plants of Oncidium
were regenerated after cocultivating protocorm-like bodies
(PLBs) with Agrobacterium tumefaciens strain LBA4404
harboring pBI121 with OMADS1. The chopped PLBs precultured
for 3 days in darkness produced more kanamycinresistant
PLBs. G10 medium containing 200 mg l-1
kanamycin was effective for the selection of transformed
lines at a frequency of 9%. The rooted plantlets were
transferred to pots, acclimated for 3 weeks in the culture
room and then moved to the greenhouse. OMADS1 transgene
was detected in transgenic lines by PCR, Southern
blot analysis and RT-PCR were performed, and the
results confirmed that OMADS1 was expressed in these
35S::OMADS1 transgenic plants. CaMV35S::OMADS1
transgenic Oncidium orchid plants flowered significantly
earlier, produced more flowers and pseudobulbs than nontransgenic
plants. The flower organ conversions were not
observed in 35S::OMADS1 transgenic flowers of Oncidium.
This is the first report on the ectopic expression of
MADS box gene in O. Gower Ramsey using a simple and
efficient gene transfer protocol.