Abstract
Plant architecture is a major factor affecting crop management and yield. The erect leaf phenotype is a key trait for improving light capture, reducing water loss, optimizing space utilization, and facilitating the chemical and biological control of arthropods and pathogens, especially those infesting/infecting abaxial leaf surfaces. This phenotype has been associated with Tiller Angle Control 1 (TAC1)-like genes across many herbaceous and tree species. Our previous genomic and genetic analyses of the erect leaf phenotype in tomato (Solanum lycopersicum) indicated that this trait is controlled by a semi-dominant locus, Erl, on chromosome 10. We discovered that this phenotype was in tight linkage with a candidate loss-of-function mutation in Solyc10g009320, an ortholog of TAC1-like genes. Therefore, editing this gene might confirm its function and enable the fine-tuned manipulation of aboveground tomato plant architecture. Here, we utilized a CRISPR/Cas9 genome editing system to confirm the complete genetic association of the erect leaf phenotype in tomato by knocking out Solyc10g009320 in tomato cultivar 'Micro-Tom'. In addition, we analyzed the effects of editing this gene on the overall plant phenotype as well as physiological and agronomic performance. Editing Solyc10g009320 alleles in tomato lays the foundation for the large-scale generation of superior genotypes, paving the way for the development of elite cultivars with an erect leaf phenotype. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42994-025-00220-9.