A fast neutron mutant resource for Ipomoea purpurea reveals dose-dependent genomic and phenotypic variation

Abstract

A central goal in evolutionary biology is to understand the genomic basis of phenotypic traits, yet this pursuit is often constrained by a lack of accessible phenotypic and genetic variation, particularly in non-model organisms. Fast neutron irradiation offers a powerful approach for generating such variation, as it does not require prior genomic resources, established transformation systems, or reference mutant collections. Here, we describe the development and characterization of the first fast neutron mutant library in Ipomoea purpurea (common morning glory), a noxious agricultural weed and established model system in evolutionary ecology. We exposed an I. purpurea reference genotype to three levels of irradiation and developed 1,043 lines third generation lines and characterized the phenotypic and genetic variation in a subset of 200. Phenotypic screens identified seven mutant lines exhibiting eleven distinct phenotypes, and revealed higher phenotypic variance for anther-stigma distance, flower number, and pollen count relative to a non-irradiated control line. We further identified genetic variation across eight phenotypic traits among the mutant lines. Together, these results show that fast neutron mutagenesis generates novel phenotypic and genetic variation in ecologically relevant traits, offering the research community a new genomic resource for an established model in evolutionary ecology.