The Arabidopsis transcription factor PHR1 is essential for adaptation to high light and retaining functional photosynthesis during phosphate starvation

TY - JOUR

T1 - The Arabidopsis transcription factor PHR1 is essential for adaptation to high light and retaining functional photosynthesis during phosphate starvation

AU - Nilsson, Lena

AU - Lundmark, Maria Therese

AU - Jensen, Poul Erik

AU - Nielsen, Tom Hamborg

PY - 2012/1

Y1 - 2012/1

N2 - The transcription factor PHR1 (PHOSPHATE STARVATION RESPONSE 1; encoded by gene At4g28610) is central for adaptation to phosphate deficiency in Arabidopsis (Arabidopsis thaliana). A rapid turnover of phosphate pools in the leaves is essential for energy transfer and metabolism within photosynthesis, and consequently, we hypothesized that PHR1 is needed for adaptation to high-light stress during P deficiency. We analyzed three Arabidopsis plant lines: wild-type, a transgenic PHR1 overexpressor line and a knockout mutant, phr1. The plants were grown under phosphate-limiting and sufficient conditions and exposed to different light conditions. Photosynthetic activity and light stress of the leaves were characterized by analyzing accumulation of carbohydrates, chlorophyll fluorescence, immunoblot detection of photosystem subunits and anthocyanin accumulation. Compared to the wild-type and the overexpressor line, the phr1 mutant has decreased levels of phosphate, anthocyanins and carbohydrates during combined P deficiency and light stress. The stressed mutant also has strongly decreased photosystem II (PSII) quantum efficiency, and shows degradation of the core units of PSII demonstrating extensive irreversible photodamage. We conclude that PHR1 is needed for the metabolic balance, for retaining P i levels and for inducing anthocyanin production, and during P deficiency PHR1 is vital for adaptations to avoid permanent damage to photosystems during high-light conditions.

AB - The transcription factor PHR1 (PHOSPHATE STARVATION RESPONSE 1; encoded by gene At4g28610) is central for adaptation to phosphate deficiency in Arabidopsis (Arabidopsis thaliana). A rapid turnover of phosphate pools in the leaves is essential for energy transfer and metabolism within photosynthesis, and consequently, we hypothesized that PHR1 is needed for adaptation to high-light stress during P deficiency. We analyzed three Arabidopsis plant lines: wild-type, a transgenic PHR1 overexpressor line and a knockout mutant, phr1. The plants were grown under phosphate-limiting and sufficient conditions and exposed to different light conditions. Photosynthetic activity and light stress of the leaves were characterized by analyzing accumulation of carbohydrates, chlorophyll fluorescence, immunoblot detection of photosystem subunits and anthocyanin accumulation. Compared to the wild-type and the overexpressor line, the phr1 mutant has decreased levels of phosphate, anthocyanins and carbohydrates during combined P deficiency and light stress. The stressed mutant also has strongly decreased photosystem II (PSII) quantum efficiency, and shows degradation of the core units of PSII demonstrating extensive irreversible photodamage. We conclude that PHR1 is needed for the metabolic balance, for retaining P i levels and for inducing anthocyanin production, and during P deficiency PHR1 is vital for adaptations to avoid permanent damage to photosystems during high-light conditions.

U2 - 10.1111/j.1399-3054.2011.01520.x

DO - 10.1111/j.1399-3054.2011.01520.x

M3 - Journal article

C2 - 21910737

SN - 0031-9317

VL - 144

SP - 35

EP - 47

JO - Physiologia Plantarum

JF - Physiologia Plantarum

IS - 1

ER -