Core Viewpoint - The article discusses the development of a novel in planta directed evolution system called GRAPE, which utilizes engineered geminivirus replicons to enhance crop breeding by rapidly generating superior alleles for plant genes [4][11]. Group 1: Directed Evolution Technology - Directed evolution technology can provide improved or entirely new biological functions to target genes in a short time, addressing the bottleneck in crop breeding due to limited existing genetic resources [3][11]. - Current directed evolution systems established in microbial and animal cells are not suitable for plant genes due to the unique post-translational modifications and regulatory networks in plants [3][6]. Group 2: GRAPE System Development - The GRAPE system was developed by engineering geminivirus replicons to create a rapid and universal in planta directed evolution system [4][7]. - The system allows for the coupling of the biological function of target genes with the rolling-circle replication mechanism of the virus, enabling efficient screening and enrichment of gene variants [6][7]. Group 3: Applications and Achievements - The GRAPE system successfully achieved rapid directed evolution of various plant immune receptors, including NRC3 and Pikm-1, enhancing their functionality and resistance to pathogens [8][9]. - The system demonstrated its versatility by allowing multiple different genes to undergo functional evolution, showcasing its potential as a powerful protein engineering platform for plants [9][11]. Group 4: Impact and Future Prospects - The GRAPE system can complete the screening of up to 10 target gene variants within 4 days on a single tobacco leaf, providing a rapid and efficient platform for molecular breeding and synthetic biology research [11]. - This technological advancement fills a significant gap in plant biology and is expected to have a substantial impact on the rapidly evolving field of plant molecular breeding [11].