Photoreceptor activity contributes to contrasting responses to shade in cardamine and arabidopsis seedlings

Abstract

Plants have evolved two major ways to deal with nearby vegetation or shade: avoidance and tolerance. Moreover, someplants respond to shade in different ways; for example, Arabidopsis (Arabidopsis thaliana) undergoes an avoidance responseto shade produced by vegetation, but its close relativeCardamine hirsutatolerates shade. How plants adopt oppositestrategies to respond to the same environmental challenge is unknown. Here, using a genetic strategy, we identified theC.hirsuta slender in shade1mutants, which produce strongly elongated hypocotyls in response to shade. These mutants lackthe phytochrome A (phyA) photoreceptor.