Activity Analysis Of Transcriptional Regulation Factors Of Banana ACC Oxidase Gene And Promoter Of Banana Lectin Gene

There are two systems which regulate ethylene production in respiration climacteric fruit. System I is ethylene auto-inhibitory, functions during normal vegetative growth, and is responsible for basal levels of ethylene present in all tissues. In System II, ethylene is auto-stimulatory and operates in climacteric fruit and during petal senescence.ACO and ACS can play key roles in the process of system I transferring to System II. Based on this fact, our lab had cloned 6 candidate transcriptional factors (TF) of ACO1 gene which expressed specifically in banana fruit by yeast one-hybrid.We selected three of candidate transcriptional factors (TR1, TR14, and TR28) to research. The GUS gene of PVKH-35S-GUS-pA vector was replaced by TR1, TR14, and TR28's cDNA sequence to construct expression vectors PVKH-1, PVKH-14, PVKH-28. At the same time, we replaced the 35s promoter of pBI121 by ACO1's promoter to construct reporter vector pBIACO. Expression vectors PVKH-1, PVKH-14, PVKH-28 respectively were co-transformed with reporter vector pBIACO into banana fruit. Transient expression of GUS was used to test the interaction between candidate transcriptional factors and ACO1 promoter. The results of transient expression of GUS indicated that TR1, TR14, and TR28 all increased expression of the report gene to different extent. So we supposed TR1, TR14, and TR28 were likely to be transcriptional regulation factor and we still need other experiments to determine their function.In our lab, we have proven that MuMADS1 gene's expression reached to the peak on the 20^th day after harvest. The rise of the climacteric was ahead of the respiration and ethylene, and the time of reaching to peak was also just the case. By the result of expression,we could predict that its function may be related to the fruit ripening in the latter days of the fruit development.Using the MuMADS1 gene,recombinant sense and antisense vector were constructed and co-transformed with reporter vector pBIACO. It was analyzed whether they could regulate promoter activity of ACO1.Our data indicated co-transformation of antisense vector and reporter vector caused a decrease in ACO promoter activity, but ACO promoter activity did not changed a lot after co-transformation of sense vector and reporter vector. This supplied that MuMADS1 gene may be related to the fruit ripening.