Variation in regulatory DNA is thought to be a major factor driving phenotypic variation in wild species as well as domestication of cultivated plants. Enhancers, a type of regulatory DNA sequence, regulate target gene expression in a spatiotemporal manner and can be relatively distal to their target genes, thus making them difficult to characterize. We performed a genome-wide association study and identified genetic variants associated with aspects of root system architecture in a collection of domesticated and wild tomato accessions. Using a massively parallel reporter assay, we tested and confirmed their relative allelic activity in vivo. A gene, PERI, associated with one of these variants is precisely spatiotemporally expressed in lateral root precursor cells. PERI expression varies according to its allele variant in cultivars within the association mapping panel and is required for lateral root development. Collectively, these data demonstrate the importance of enhancers in shaping root system architecture in tomato and its wild relatives.

Bio: Siobhan specializes in the regulation of gene expression in plant roots. Her research integrates
genomics, molecular biology, and bioinformatics to understand how transcriptional
networks control root development and response to environmental stress. By dissecting
these complex regulatory pathways, she aims to uncover the mechanisms that enable
plants to adapt to changing conditions, contributing to advancements in agricultural
biotechnology and crop improvement. Her work is pivotal in developing resilient plant
varieties for sustainable agriculture.