Suitability of two distinct approaches for the high-throughput study of the post-embryonic effects of embryo-lethal mutations in Arabidopsis

Several hundred genes are required for embryonic and gametophytic development in the model plant Arabidopsis thaliana, as inferred from the lethality of their mutations. Despite many of these genes are expressed throughout the plant life cycle, the corresponding mutants arrest at early stages, preventing the study of their post-embryonic functions by conventional methods. Clonal analysis represents an effective solution to this problem by uncovering the effects of embryo-lethal mutations in sectors of mutant cells within an otherwise normal adult plant. In this pilot study, we have evaluated the suitability of two sector induction methods for the large-scale study of the post-embryonic effects of embryo-lethal (emb) mutations in Arabidopsis. In line with the interests of our laboratory, we selected 24 emb mutations that damage genes that are expressed in wild-type vegetative leaves but whose effects on leaf development remain unknown. For the induction of mutant sectors in adult plants, we followed one approach based on the X-ray irradiation of ‘cell autonomy’ (CAUT) lines, and another based on the site-specific excision of transgenes mediated by Cre recombinase. We conclude that both methods are time-consuming and difficult to scale up, being better suited for the study of emb mutations on a case-by-case basis.