RELATe enables genome-scale engineering in fungal genomics.

Abstract

CRISPR-Cas9-based screening with single-guide RNA (sgRNA) libraries has emerged as a revolutionary tool for comprehensive analysis of genetic elements. However, genome-scale sgRNA libraries are currently available only in a few model organisms. The traditional approach is to synthesize thousands to tens of thousands of sgRNAs, which is laborious and expensive. We have developed a simple method, RELATe (restriction/ligation coupled with <i>Agrobacterium</i>-mediated transformation), to generate sgRNA libraries from 10 μg of genomic DNA, targeting over 98% of the protein-coding genes in the human fungal pathogen <i>Cryptococcus neoformans</i> Functional screens identified 142 potential <i>C. neoformans</i> genes contributing to blood-brain barrier penetration. We selected two cryptococcal genes, <i>SFP1</i> and <i>WDR1</i>, for a proof-of-concept demonstration that RELATe-identified genes are relevant to <i>C. neoformans</i> central nervous system infection. Our RELATe method can be used in many other fungal species and is powerful and cost-effective for genome-wide high-throughput screening for elucidating functional genomics.