A single-cell screening platform accelerates functional genetics in plants.

Abstract

Elucidating gene function in highly redundant genetic programs such as signaling pathways is challenging in model and nonmodel plants with current whole-plant genetic screening tools. Many of these challenges could be overcome if screens were instead carried out using individual cells harboring genetic perturbations. Here we report a single-cell screening platform, PIVOT (protoplast isolation after virus overexpression in planta), to accelerate identification and functional characterization of plant genes. We use Nicotiana benthamiana as a heterologous host to test gene libraries arrayed in a single leaf. PIVOT harnesses viral superinfection exclusion to ensure single multiplicity of infection per cell during pooled library delivery. Additionally, we engineer a cell-surface protein as a phenotypic marker for isolating cells of interest from a heterogeneous population. Using this system, we recover regulators of cytokinin signaling from an Arabidopsis open reading frame library. We anticipate PIVOT will be broadly applicable for high-throughput, single-cell functional genetic screening across the plant kingdom.