Molecular cloning and functional characterization of patatin gene promoters from potato cultivars

Abstract

In potato (Solanum tuberosum L.) tuber, patatin refers to the most abundant glycoprotein (~40 kDa), encoded by a large multigene family comprising of two major classes. The class I genes are predominantly expressed in tubers, while class II genes are poorly expressed in certain cell types of tubers and root tips. Particularly, class I patatin gene promoters are attractive molecular tools to the researchers because of their tuber specificity, inducible nature of expression and for studying multiple facets of transcriptional regulation. In comparison to its large family size in potato genome, we only know a few members of class I patatin genes with regard to their structure and function till to date. In this context, this study is quite relevant. Here, for the first time, we report the isolation of five new partial class I patatin genes, designated as StPM01 (GenBank Acc. No. JX124230), StPM02 (Acc. No. JX124231); StPK01 (Acc. No. JX124228), StPK03 (Acc. No. JX124229); and StPN02 (Acc. No. JX124227) from high yielding and commercially important Indian potato cultivars Kufri Chandramukhi (KCM), Kufri Chipsona-1 (CS-1), and Kufri Jyoti (KJ) by PCR approach. Sequence analyses clearly revealed that their 5and#61602;-flanking regions were found to vary significantly interms of insertions/deletions apart from cumulative point mutations and none of them was found to be identical with any other class I patatin gene family members reported to date. The major conspicuous difference between StPM01 and StPM02 was due to the presence or absence of a 69-bp region in their 5and#61602;-flanking regions. Likewise, a major 487 bp insertion in StPN02 made it very distinct, the feature found to be mostly uncommon in other members. A number of diverse cis-regulatory sequence motifs were predicted and many of them were not documented earlier.