Tapetum specific TA29 promoter is regulated by cis- elements binding to positive and negative regulators

Abstract

The TA29 gene from Nicotiana tabacum was one of the first tapetum-specific genes identified in 1990. Its promoter has been successfully used to develop barnase/barstar gene-based male sterility and restorer transgenic lines for hybrid seed production in crops such as mustard. Despite its biotechnological significance, no major studies have been conducted to delineate the regulatory mechanisms of its promoter. The presented work identifies critical cis-elements of the promoter, starting with in-silico analysis followed by functional validation through mutational studies and promoter activity analysis in transgenic tobacco lines. This work led to the identification of cis-elements that are putative binding sites for the transcription factors NtMYB12, NtGT-1a, NtNAG1, and NtLZ-HD. The binding sites for NtMYB12, NtGT-1a, and NtNAG1 act as positive regulators, whereas the binding site for NtLZ-HD functions as a negative regulator.