Photoreceptor Activity Contributes to Contrasting Responses to Shade in Cardamine and Arabidopsis Seedlings. Issue 11 (17th September 2019)

• Record Type: Journal Article
• Authors: Molina-Contreras, Maria Jose; Paulišić, Sandi; Then, Christiane; Moreno-Romero, Jordi; Pastor-Andreu, Pedro; Morelli, Luca; Roig-Villanova, Irma; Jenkins, Huw; Hallab, Asis; Gan, Xiangchao; Gomez-Cadenas, Aurelio; Tsiantis, Miltos; Rodríguez-Concepción, Manuel; Martínez-García, Jaime F.
• Is Part Of: The Plant Cell. Volume 31:Issue 11(2019)
• Page Start: 2649
• Page End: 2663
• Publication Date: 2019-09-17
• DOI: 10.1105/tpc.19.00275
• Languages: English
• ISSNs: 1040-4651

Abstract

Abstract : The lack of a shade-induced hypocotyl elongation response in Cardamine hirsuta results from the enhanced repressor activity of the phytochrome A photoreceptor. Abstract: Plants have evolved two major ways to deal with nearby vegetation or shade: avoidance and tolerance. Moreover, some plants respond to shade in different ways; for example, Arabidopsis ( Arabidopsis thaliana ) undergoes an avoidance response to shade produced by vegetation, but its close relative Cardamine hirsuta tolerates shade. How plants adopt opposite strategies to respond to the same environmental challenge is unknown. Here, using a genetic strategy, we identified the C. hirsuta slender in shade1 mutants, which produce strongly elongated hypocotyls in response to shade. These mutants lack the phytochrome A (phyA) photoreceptor. Our findings suggest that C. hirsuta has evolved a highly efficient phyA-dependent pathway that suppresses hypocotyl elongation when challenged by shade from nearby vegetation. This suppression relies, at least in part, on stronger phyA activity in C. hirsuta ; this is achieved by increased ChPHYA expression and protein accumulation combined with a stronger specific intrinsic repressor activity. We suggest that modulation of photoreceptor activity is a powerful mechanism in nature to achieve physiological variation (shade tolerance versus avoidance) for species to colonize different habitats.