EXPRESSION OF ETHYLENE RECEPTOR GENE FROM ONCIDIUM 'GOWER RAMSEY' DURING FLOWER SENESCENCE

The process of flower senescence is influenced by the plant hormone, ethylene. In Arabidopsis, ethylene perception is controlled by a family of five genes, including ETHYLENE RESPONSE 1 (ETR1), ETHYLENE RESPONSE SENSOR 1 (ERS1), ETHYLENE RESPONSE 2 (ETR2), ETHYLENE RESPONSE SENSOR 2 (ERS2) and ETHYLENE-INSENSITIVE 4 (EIN4). They fall into two subfamilies based on their sequence similarities. In flower, it has been reported that a similar set of genes is also involved. The changes in gene expression in ethylene signaling during senescence of orchids flowers were studied. Total RNA was extracted from the self-pollinated Oncidium ‘Gower Ramsey’ flowers followed with reverse transcriptase-polymerase chain reaction (RT-PCR). Previously, an ethylene gene named ER2₅, was cloned, which encodes for a protein that has a missing region in the histidine kinase domain as compared to the sequence of ER protein for a similar orchid hybrid. In this study, the result demonstrated that the expression of the isolated gene was successfully detected by real-time RT-PCR at a very low level in the tested flower tissues, as well as in roots. Results suggest that ER2₅ may be involved in the development of different plant tissues.