Convergent evolution of desiccation tolerance in grasses

Abstract

Desiccation tolerance has evolved repeatedly in plants as an adaptation to survive extreme environments. Plants use similar biophysical and cellular mechanisms to survive life without water, but convergence at the molecular, gene, and regulatory levels remains to be tested. Here, we explore the evolutionary mechanisms underlying the recurrent evolution of desiccation tolerance across grasses. We observed substantial overlap in gene duplication and expression associated with desiccation, and syntenic genes of shared origin are activated across species, indicative of parallel evolution. In other cases, similar metabolic pathways are induced, but using different gene sets, pointing towards phenotypic convergence. Species-specific mechanisms supplement these shared core mechanisms, underlining the complexity and diversity of evolutionary adaptations. Our findings provide insight into the evolutionary processes driving desiccation tolerance and highlight the roles of parallel mutation and complementary pathway adaptation in response to environmental challenges.