Genetic and Molecular analysis of trichome development in Arabis alpina $ (PNAS)

Trichomes (plant hairs), arise from epidermal cells of plants. The molecular mechanism involved in the development of trichomes of plants has been well studied in Arabidopsis thaliana. In this paper, Chopra et al.  have identified key regulators of leaf trichome development in Arabis alpina, a species that diverged from A. thaliana about 26-40 million years ago. Using forward genetics, multiple regulators of trichome development were identified in A. alpina including mutants that cause a glabrous (trichome lacking) phenotype. Although most of the genes involved in trichome development of A. alpina were similar to those in A. thaliana, some regulators have diversified in their function. One of the major findings concerns the role of GL3 (GLABRA3), which when mutated causes a strong phenotype in A. alpina but requires simultaneous mutation in EGL3 (ENHANCER OF GLABRA3) to cause a strong glabrous phenotype in A. thaliana. Overall the results from this paper suggests that with close relationship between species, gene functions are comparable but the divergence is sufficient to study some difference in some molecular players of development. (Summary by Suresh Damodaran)  Proc. Natl. Acad. Sci. USA 10.1073/pnas.1819440116