Comparative expression analysis in three Brassicaceae species revealed compensatory changes of the underlying gene regulatory network

Abstract

Trichomes are regularly distributed on the leaves of Arabidopsis thaliana. The gene regulatory network underlying trichome patterning involves more than 15 genes. However, it is possible to explain patterning with only five components. This raises the questions about the function of the additional components and the identification of the core network. In this study, we compare the relative expression of all patterning genes in A. thaliana, A. alpina and C. hirsuta by qPCR analysis and use mathematical modelling to determine the relative importance of patterning genes. As the involved proteins exhibit evolutionary conserved differential complex formation, we reasoned that the genes belonging to the core network should exhibit similar expression ratios in different species. However, we find several striking differences of the relative expression levels. Our analysis of how the network can cope with such differences revealed relevant parameters that we use to predict the relevant molecular adaptations in the three species.

Evolution of gene regulatory network architectures regulating root hair patterning in superrosid species

“…In this species, files in which every cell develops as a hair cell are interspersed with those containing mainly nonhair cells but also a high number of ectopic hair cells (30% in Paj and 40% in pep1-1; Chopra et al, 2014). Arabis alpina encodes orthologs of all components of the GRN regulating root hair patterning in Arabidopsis (Chopra et al, 2019;Pietsch et al, 2023), including one WER ortholog (Chopra et al, 2019;. Specifically, it has one TTG1-like WDR protein (Chopra et al, 2014).…”