A polymorphic (GA/CT)n- SSR influences promoter activity of Tryptophan decarboxylase gene in Catharanthus roseus L. Don

Abstract

Simple Sequence Repeats (SSRs) of polypurine-polypyrimidine type motifs occur very frequently in the 5′ flanks of genes in plants and have recently been implicated to have a role in regulation of gene expression. In this study, 2 accessions of Catharanthus roseus having (CT)8 and (CT)21 varying motifs in the 5′UTR of Tryptophan decarboxylase (Tdc) gene, were investigated for its role in regulation of gene expression. Extensive Tdc gene expression analysis in the 2 accessions was carried out both at the level of transcription and translation. Transcript abundance was estimated using Northern analysis and qRT-PCR, whereas the rate of Tdc gene transcription was assessed using in-situ nuclear run-on transcription assay. Translation status of Tdc gene was monitored by quantification of polysome associated Tdc mRNA using qRT-PCR. These observations were validated through transient expression analysis using the fusion construct [CaM35S:(CT)8–21:GUS]. Our study demonstrated that not only does the length of (CT)n -SSRs influences the promoter activity, but the presence of SSRs per se in the 5′-UTR significantly enhances the level of gene expression. We termed this phenomenon as “microsatellite mediated enhancement” (MME) of gene expression. Results presented here will provide leads for engineering plants with enhanced amounts of medicinally important alkaloids.

Alterations in the 5′ untranslated region of the 5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS) gene influence EPSPS overexpression in glyphosate‐resistant Eleusine indica

“…The mutation length of the 5 ′ UTR Py-rich stretch motif influences promoter activity of the tryptophan decarboxylase (tdc) gene in Catharanthus roseus. 36 In our present study, the 5 ′ UTR Py-rich stretch motif mainly existed in the L-5UPS form in the R biotypes with high EPSPS expression, whereas the 5 ′ UTR Py-rich stretch motif mainly existed in the S-5UPS form in the S biotype with low EPSPS expression after glyphosate treatment (Fig. 4).…”

“…Studies on the promoter function of the amorpha‐4,11‐diene synthase (ADS) gene in Artemisia annua and the high‐molecular‐weight glutenin subunit (HMW‐GS) gene in Triticum aestivum demonstrated that the 5′ UTR Py‐rich stretch elements were important factors in the enhancement of the expression of the ADS and HMW‐GS genes. The mutation length of the 5′ UTR Py‐rich stretch motif influences promoter activity of the tryptophan decarboxylase ( tdc ) gene in Catharanthus roseus . In our present study, the 5′ UTR Py‐rich stretch motif mainly existed in the L‐5UPS form in the R biotypes with high EPSPS expression, whereas the 5′ UTR Py‐rich stretch motif mainly existed in the S‐5UPS form in the S biotype with low EPSPS expression after glyphosate treatment (Fig.…”

GATA and Phytochrome Interacting Factor Transcription Factors Regulate Light-Induced Vindoline Biosynthesis in Catharanthus roseus

“…Before infiltration, effector, reporter, and internal control solutions were combined at a 1:1:1 ratio and mixed well. Infiltration of N. benthamiana leaves was performed as previously described (Kumar and Bhatia, 2016). Two days after infiltration, leaf discs were collected, frozen in liquid nitrogen, and ground to powder for protein extraction.…”

Characterization of Esterase Genes Involving Malathion Detoxification and Establishment of an RNA Interference Method in Liposcelis bostrychophila

“…All the above effects caused by SSR variations in genes can lead to phenotypic changes in organisms (Li et al, 2004). For example, (CT) n -SSRs located in the 5 -UTR of tryptophan decarboxylase will influence the promoter activity and thus significantly enhances the level of gene expression in plants (Kumar and Bhatia, 2016). In Myzus persicae, the expansion of a di-nucleotide microsatellite in the promoter region of a P450 gene lead to its overexpression, and this process enhanced the resistance to neonicotinoid insecticides in this aphid (Bass et al, 2013).…”