Optogenetic Methods in Plant Biology

Abstract

Optogenetics is a technique employing natural or genetically engineered photoreceptors in transgene organisms to manipulate biological activities with light. Light can be turned on or off, and adjusting its intensity and duration allows optogenetic fine-tuning of cellular processes in a noninvasive and spatiotemporally resolved manner. Since the introduction of Channelrhodopsin-2 and phytochrome-based switches nearly 20 years ago, optogenetic tools have been applied in a variety of model organisms with enormous success, but rarely in plants. For a long time, the dependence of plant growth on light and the absence of retinal, the rhodopsin chromophore, prevented the establishment of plant optogenetics until recent progress overcame these difficulties. We summarize the recent results of work in the field to control plant growth and cellular motion via green light–gated ion channels and present successful applications to light-control gene expression with single or combined photoswitches in plants. Furthermore, we highlight the technical requirements and options for future plant optogenetic research.

Phytochrome phosphorylation in plant light signaling

“…Thus, the functional roles of the OPM necessitates additional studies by focusing on the regulation of phytochrome kinase activity. Moreover, the regulation of phytochrome phosphorylation may have potentials for biotechnological applications, including optogenetics for manipulating biological activities with light ( Konrad et al., 2023 ). Therefore, understanding the molecular and regulatory mechanisms of phytochromes via reversible phosphorylation and their kinase activity will bring further insights into the broader signaling networks underlying plant light perception and adaptation.…”

New horizons in light control of plant photomorphogenesis and development

“…Our understanding of functional components and mechanistic connections in light signalling at the molecular level has reached a niveau that allows to get beyond fundamental research of photoperception and to use this knowledge for the construction of optogenetic tools. While this field of science has tremendous success in various areas of the life sciences such as neuroscience or animal research, optogenetics in plants is lagging behind mostly because of interference with plant internal light-dependent processes (Christie and Zurbriggen, 2021;Konrad et al, 2023). Major obstacles in the past were the principle requirement of plants for light as energy source in photosynthesis (requiring growth under light/dark cycles) as well as the sophisticated internal light signalling networks that show high degrees of redundancy providing high compensation capabilities of genetic manipulations.…”

Emerging optogenetics technologies in biomedical applications

“…1,2 Examples of light regulation include the phototropism, lightdependent growth response of plants, the visual perception of animals, and the photophilic movement of bacteria. [3][4][5][6][7][8] Optogenetics has several advantages over other tools for targeted regulation of cells, such as chemical methods, pure genetic methods, and hybridization methods. [9][10][11] By employing light as a trigger, optogenetics offers meticulous temporal and spatial control over cellular expression, resulting in prompt responsiveness and high-intensity manipulability.…”

“…Optogenetics is an advanced technology that utilizes a vector to transfect a photosensitive protein, responsive to light, into specific target organs, cells, or genes, enabling precise regulation of cellular activities 1,2 . Examples of light regulation include the phototropism, light‐dependent growth response of plants, the visual perception of animals, and the photophilic movement of bacteria 3–8 . Optogenetics has several advantages over other tools for targeted regulation of cells, such as chemical methods, pure genetic methods, and hybridization methods 9–11 .…”