Fluorescence-based whole plant imaging and phenomics

Abstract

Reverse genetics approaches have revolutionized plant biology and agriculture. Phenomics has the prospect of bridging plant phenotypes with genes, including transgenes, to transform agricultural fields1. Genetically-encoded fluorescent proteins (FPs) have transformed studies in gene expression, protein trafficking, and plant physiology. While the first instance of plant canopy imaging of green fluorescent protein (GFP) was performed over 20 years ago2, modern phenomics has largely ignored fluorescence as a transgene indicator despite the burgeoning FP color palette currently available to biologists3-5. Here we show a new platform for standoff imaging of plant canopies expressing a wide variety of FP genes in leaves. The platform, the fluorescence-inducing laser projector (FILP), uses a low-noise camera to image a scene illuminated by compact diode lasers of various colors and emission filters to phenotype transgenic plants expressing multiple constitutive or inducible FPs. Of the 20 FPs screened, we selected the top performing candidates for standoff phenomics at [≥] 3 m using FILP in a laboratory-based laser range. Included in demonstrated applications is the performance of an osmotic stress-inducible synthetic promoter selected from a high throughput library screen. While FILP has unprecedented versatility as a laboratory platform, we envisage future iterations of the system for use in automated greenhouse or even drone-fielded versions of the platform for crop screening.