Breaking-off tissue specific activity of the oil palm metallothionein-like gene promoter in T(1) seedlings of tomato exposed to metal ions

Functional characterization of the MSP-C6 promoter as a potential tool for mesocarp-preferential expression of transgenes

Modification of lipid composition in the mesocarp tissue of oil palm involves genetic manipulation of multiple genes. More than one mesocarp-preferential promoter is necessary for the expression of individual transgenes in the same plant to obviate transcriptional gene silencing. This study aimed to identify genes that are preferentially expressed in the mesocarp tissue and characterize selected candidate mesocarp-preferential promoters. Ten transcripts that were preferentially expressed in the mesocarp tissue were identified from the analysis of 82 transcriptome datasets of 12 different oil palm tissues. The expression of two candidate genes, MSP-C1 and MSP-C6, was verified to be preferentially expressed in the mesocarp tissues and shown to have a low expression level in non-mesocarp tissues by reverse transcription quantitative real-time PCR (RT-qPCR). MSP-C6 promoter fragments of different lengths were transformed into tomato plants for further characterization. Both unripe and ripe fruits of transgenic tomato plants transformed with a construct harboring the MSP-C6-F1 (2014 bp) promoter were shown to have high beta-glucuronidase (GUS) activities. The findings of this study suggest the potential applications of the MSP-C6 promoter as a molecular tool for genetic engineering of novel traits in fruit crops.

Plant promoters: an approach of structure and function

With current advances in genomics, several technological processes have been generated, resulting in improvement in different segments of molecular research involving prokaryotic and eukaryotic systems. A widely used contribution is the identification of new genes and their functions, which has led to the elucidation of several issues concerning cell regulation and interactions. For this, increase in the knowledge generated from the identification of promoters becomes considerably relevant, especially considering that to generate new technological processes, such as genetically modified organisms, the availability of promoters that regulate the expression of new genes is still limited. Considering that this issue is essential for biotechnologists, this paper presents an updated review of promoters, from their structure to expression, and focuses on the knowledge already available in eukaryotic systems. Information on current promoters and methodologies available for studying their expression are also reported.