Plant Synthetic Promoters: Advancement and Prospective

Abstract

Native/endogenous promoters have several fundamental limitations in terms of their size, Cis-elements distribution/patterning, and mode of induction, which is ultimately reflected in their insufficient transcriptional activity. Several customized synthetic promoters were designed and tested in plants during the past decade to circumvent such constraints. Such synthetic promoters have a built-in capacity to drive the expression of the foreign genes at their maximum amplitude in plant orthologous systems. The basic structure and function of the promoter has been discussed in this review, with emphasis on the role of the Cis-element in regulating gene expression. In addition to this, the necessity of synthetic promoters in the arena of plant biology has been highlighted. This review also provides explicit information on the two major approaches for developing plant-based synthetic promoters: the conventional approach (by utilizing the basic knowledge of promoter structure and Cis-trans interaction) and the advancement in gene editing technology. The success of plant genetic manipulation relies on the promoter efficiency and the expression level of the transgene. Therefore, advancements in the field of synthetic promoters has enormous potential in genetic engineering-mediated crop improvement.

Temporally gene knockout using heat shock–inducible genome‐editing system in plants

“…Synthetic promoters also have the advantage of enhancing or reducing the promoter activity by rearranging cis ‐elements via altering their copy number and spacing. Numerous inducible synthetic promoters with temporal and spatial expression patterns, biotic or abiotic stress susceptibility, and chemical or hormone responsive have been developed in plants (Khan et al., 2023; Rushton, 2016). Combing such recombinant/chimeric promoters with the CRISPR/Cas9‐based genome‐editing system is becoming increasingly popular in genetic manipulation to protect plants against adverse climatic conditions, plant diseases, and pests (Omelina et al., 2022).…”

Major viral diseases in grain legumes: designing disease resistant legumes from plant breeding and OMICS integration

“…Adequate advances have been made in designing SPs and STFs for regulating specific genes involved in multiple trait improvement in crop plants, including biotic and stress tolerance ( Dey et al., 2015 ; Yasmeen et al., 2023 ). Synthetic promoters are designed rationally and constructed for specific binding to upstream motifs or native core promoter sites ( Khan et al., 2023 ) so that external stimuli can regulate gene expression ( Rushton et al., 2002 ). This strategy is mostly suitable for enhancing biotic stress tolerance when pathogen-inducible SPs can be employed against diverse pathogens ( Khan et al., 2023 ), as exemplified against Ascochyta rabiei ( Shokouhifar et al., 2019 ).…”

“…Synthetic promoters are designed rationally and constructed for specific binding to upstream motifs or native core promoter sites ( Khan et al., 2023 ) so that external stimuli can regulate gene expression ( Rushton et al., 2002 ). This strategy is mostly suitable for enhancing biotic stress tolerance when pathogen-inducible SPs can be employed against diverse pathogens ( Khan et al., 2023 ), as exemplified against Ascochyta rabiei ( Shokouhifar et al., 2019 ). Similarly, STFs can be constructed by fusing various DNA binding domains (DBDs) with an activator/repressor domain and nuclear localization signals for regulated gene expression in plants.…”

Cacao pod transcriptome profiling of seven genotypes identifies features associated with post-penetration resistance to Phytophthora palmivora

“…While identifying differentially regulated genes is of interest to understanding how plants respond to disease stress, there is also a need to understand how non-coding regions of plant genomes act to direct gene expression 30 . Understanding how plant promoters are organized and how regulatory DNA elements interact will allow rapid advancement of crops via both conventional breeding and the design and deployment of synthetic promoters 31 , 32 . Identification and characterization of promoter elements unique to cacao is limited.…”