Epsilon Archive for Student Projects

Abstract

Environmental conditions can strongly influence plant immunity, yet how environmental cues modulate genetically driven immune activation remains poorly understood. The Est-1 accession of Arabidopsis thaliana has a hyperactive allele of ACD6 that leads to constitutive immune activation
under controlled conditions, but has a much less pronounced phenotype in the field. This study examined the environmental modulation of ACD6-dependent immunity using a PR1:RUBY reporter, molecular analyses, phenotyping and transcriptomic approaches. The PR1:RUBY construct was developed and introduced into Col-0, Est-1, and Est-1 acd6 knockout backgrounds, and reporter responses were assessed after immune induction with heat-killed Pseudomonas
syringae. The abundance of the transcripts of PR1 and RUBY was significantly higher after treatment, and genotype-dependent differences indicated that the magnitude of the immune response was influenced by the abundance of the transcript of ACD6. Visual and image-based analyses of the
reporter activity of RUBY were also performed to complement the evidence of immune activation. To examine the environmental effects on the Est-1 phenotype, field-grown plants were sampled longitudinally over growing seasons. An efficient RNA extraction and RNA-sequencing library
preparation workflow was successfully optimized to generate RNA and sequencing libraries for these samples suitable for transcriptomic analysis. In summary, the contrasting immune phenotypes observed under controlled and field conditions suggest that environmental context influences immune activation via the ACD6 pathway, and the developed PR1:RUBY construct and optimized transcriptomic workflow offer valuable experimental tools for further exploration of the relationship between genetic immune activation and environmental context.