Čeština
EnglishActivity of the Brassinosteroid Transcription Factors BZR1 and BES1/BZR2 Blocks Developmental Reprogramming in Response to Low Phosphate Availability
Singh A.P., Fridman Y., Friedlander-Shani L., Tarkowska D., Strnad M., Savaldi-Goldstein S.
PLANT PHYSIOLOGY 166: 678-688, 2014
Keywords:
Abstract: Plants feature remarkable developmental plasticity, enabling them to respond to and cope with environmental cues, such as limited availability of phosphate, an essential macronutrient for all organisms. Under this condition, Arabidopsis roots undergo striking morphological changes, including exhaustion of the primary meristem, impaired unidirectional cell expansion and elevated density of lateral roots, resulting in shallow root architecture. Here, we demonstrate that the activity of two homologous brassinosteroid transcriptional effectors, BZR1 and BES1/BZR2, block these responses, consequently maintaining normal root development under low phosphate conditions, without impacting phosphate homeostasis. We show that phosphate deprivation shifts the intracellular localization of BES1/BZR2 to yield a lower nucleus to cytoplasm ratio, while replenishing the phosphate supply reverses this ratio within hours. Phosphate deprivation reduces the expression levels of BR biosynthesis genes and the accumulation of the bioactive brassinosteroid 28-norcastasterone. In agreement, low and high BR levels sensitize and de-sensitize root response to this adverse condition, respectively. Hence, we propose that the environmentally controlled developmental switch from deep to shallow root architecture involves a reduction in BZR1 and BES1/BZR2 levels in the nucleus, which likely plays a key role in plant adaptation to phosphate-deficient environments.
DOI: 10.1104/pp.114.245019 IEB authors: Miroslav Strnad, Danuše Tarkowská
PLANT PHYSIOLOGY 166: 678-688, 2014
Keywords:
Abstract: Plants feature remarkable developmental plasticity, enabling them to respond to and cope with environmental cues, such as limited availability of phosphate, an essential macronutrient for all organisms. Under this condition, Arabidopsis roots undergo striking morphological changes, including exhaustion of the primary meristem, impaired unidirectional cell expansion and elevated density of lateral roots, resulting in shallow root architecture. Here, we demonstrate that the activity of two homologous brassinosteroid transcriptional effectors, BZR1 and BES1/BZR2, block these responses, consequently maintaining normal root development under low phosphate conditions, without impacting phosphate homeostasis. We show that phosphate deprivation shifts the intracellular localization of BES1/BZR2 to yield a lower nucleus to cytoplasm ratio, while replenishing the phosphate supply reverses this ratio within hours. Phosphate deprivation reduces the expression levels of BR biosynthesis genes and the accumulation of the bioactive brassinosteroid 28-norcastasterone. In agreement, low and high BR levels sensitize and de-sensitize root response to this adverse condition, respectively. Hence, we propose that the environmentally controlled developmental switch from deep to shallow root architecture involves a reduction in BZR1 and BES1/BZR2 levels in the nucleus, which likely plays a key role in plant adaptation to phosphate-deficient environments.
DOI: 10.1104/pp.114.245019 IEB authors: Miroslav Strnad, Danuše Tarkowská