Biological and Molecular Components for Genetically Engineering Biosensors in Plants

Abstract

Plants adapt to their changing environments by sensing and responding to physical, biological, and chemical stimuli. Due to their sessile lifestyles, plants experience a vast array of external stimuli and selectively perceive and respond to specific signals. By repurposing the logic circuitry and biological and molecular components used by plants in nature, genetically encoded plant-based biosensors (GEPBs) have been developed by directing signal recognition mechanisms into carefully assembled outcomes that are easily detected. GEPBs allow for in vivo monitoring of biological processes in plants to facilitate basic studies of plant growth and development. GEPBs are also useful for environmental monitoring, plant abiotic and biotic stress management, and accelerating design-build-test-learn cycles of plant bioengineering. With the advent of synthetic biology, biological and molecular components derived from alternate natural organisms (e.g., microbes) and/or de novo parts have been used to build GEPBs. In this review, we summarize the framework for engineering different types of GEPBs. We then highlight representative validated biological components for building plant-based biosensors, along with various applications of plant-based biosensors in basic and applied plant science research. Finally, we discuss challenges and strategies for the identification and design of biological components for plant-based biosensors.

Engineered gamma radiation phytosensors for environmental monitoring

“…Though basal stem fluorescence does allow sensor plants to stick out from a surrounding plant canopy, new iterations of the sensor will need to improve upon the established SOG1 transcriptional switch to either lower basal fluorescence associated with growing tissue and/or increase SOG1 presence in leaf tissue types to increase fluorescence in the sensor plant's canopy. This sensor represents an indirect biosensor (Liu et al, 2022) which relies on many molecular interactions which leads to SOG1 binding the 4xRAD51 promoter. Indirect biosensors are inherently prone to more error than the direct biosensors reviewed by Liu et al (2022) where the reporter is directly activated by the stimulus, which is clear given the high level of basal fluorescence in all 4xRAD51 pro events.…”

“…This sensor represents an indirect biosensor (Liu et al, 2022) which relies on many molecular interactions which leads to SOG1 binding the 4xRAD51 promoter. Indirect biosensors are inherently prone to more error than the direct biosensors reviewed by Liu et al (2022) where the reporter is directly activated by the stimulus, which is clear given the high level of basal fluorescence in all 4xRAD51 pro events. If a direct biosensor could be devised for ionizing radiation, this could offer improvements on the current sensor design.…”

Multifactorial analysis of terminator performance on heterologous gene expression in Physcomitrella

“…Terminators are crucial for high recombinant protein yields by acting on transcription, pre-mRNA processing, mRNA stability, and translation (Moore and Proudfoot 2009 ; Zhong et al 2023 ; Liu et al 2023 ). At the start of transcription, the gene promoter and terminator interact in a process called gene looping.…”

Biosensor-assisted CRISPRi high-throughput screening to identify genetic targets in Zymomonas mobilis for high d-lactate production

“…Biosensor-assisted CRISPRi high-throughput screening that combines a CRISPR interference and a biosensor-mediated screening is a global screening method that has been used to obtain recombinant strains for biochemical production such as coumaric acid and butyrate with high titer, rate, or yield [ 31 ]. Specifically, metabolite biosensors can convert metabolite compound concentrations into fluorescence output or cell growth advantages at a single-cell level, and then achieve high-throughput screening of specific high-yield strains through FACS [ [32] , [33] , [34] ]. CRISPRi library mediated stringent gene repression could obtain a variety of strains with different gene expressions.…”