Abstract: It is known that RhETR3 plays an important role in ethylene-regulated flower opening of roses（Rosa hybrida）. Here，RhETR3 was used as a bait to screen its potential interacting proteins in rose petals by using split ubiquitin yeast two-hybrid system. Of 26 positive clones which were identified and confirmed by retransformation in yeast，a TSPO/MBR protein was isolated by RACE and was named as RhTSPO1. The full length of RhTSPO1 was 777 bp which contained a 579 bp open reading frame，encoding 192 amino acids residues. The interaction between RhETR3 and RhTSPO1 was confirmed by β-galactosidase activity test in yeast. In addition，RhTSPO1 was fused with a mCherry fluorescent protein. The resultant RhTSPO1-mCherry fusion protein was used to conduct the fluorescence co-localization with RhETR3-GFP. The results indicated that these two proteins both located in the endoplasmic reticulum. The expression of RhTSPO1 increased as flower opening in the petals of cut roses，while it started to decrease when flower reached full opening，implying that RhTSPO1 may be involved in the flower opening process.

Key words: cut rose, flower opening, ethylene receptor, protein interaction