Cloning and activity analysis of the highly expressed gene VviABCG20 promoter in seed and its activity is negatively regulated by the transcription factor VviDof14.

Half-size ATP binding cassette G (ABCG) transporters participate in the growth and development of plants by transporting substrates. The VviABCG20 gene is highly expressed in seed and plays an important role in seed development/abortion. However, little is known about the function of the VviABCG20 promoter (pVviABCG20) and its regulatory factors. In our study, we obtained pVviABCG20s from 15 seeded and seedless grape varieties and there were two types of 'a' and 'b' with 41 bp non-deletion or deletion, respectively. The pVviABCG20 activity was higher in seeds, siliques, flowers and roots of pVviABCG20-GUS Arabidopsis. The GUS activity analysis revealed that the activities of P4 (-586 bp) to P7 (-155 bp) were becoming increasingly weaker, and the P7 activity almost disappears compared with the pVviABCG20 (P0, -1604). Yeast one-hybrid and GUS activity analysis indicated that VviDof14 binds to the AAAG element in the P7' (-586 bp) fragment of the pVviABCG20 and regulated the activity negatively. The quantitative real-time PCR analysis suggested that the expression of VviDof14 in Thompson seedless seeds was higher than that in Pinot noir. Our study laid the foundation for further analysis of the functions of the pVviABCG20 and its regulator VviDof14 in grape seed development/abortion.