TY - JOUR
T1 - CHRD, a plant member of the evolutionarily conserved YjgF family, influences photosynthesis and chromoplastogenesis
AU - Leitner-Dagan, Yael
AU - Ovadis, Marianna
AU - Zuker, Amir
AU - Shklarman, Elena
AU - Ohad, Itzhak
AU - Tzfira, Tzvi
AU - Vainstein, Alexander
N1 - Funding Information:
Acknowledgments This work was supported by the Israel Science Foundation (grant No. 466/01).
PY - 2006/12
Y1 - 2006/12
N2 - Studies on the carotenoid-overaccumulating structures in chromoplasts have led to the characterization of proteins termed plastid lipid-associated proteins (PAPs), involved in the sequestration of hydrophobic compounds. Here we characterize the PAP CHRD, which, based on sequence homology, belongs to a highly conserved group of proteins, YER057c/YjgF/UK114, involved in the regulation of basic and vital cellular processes in bacteria, yeast and animals. Two nuclear genes were characterized in tomato plants: one (LeChrDc) is constitutively expressed in various tissues and the other (LeChrDi) is induced by stress in leaves and is upregulated by developmental cues in floral tissues. Using RNAi and antisense approaches, we show their involvement in biologically significant processes such as photosynthesis. The quantum yield of photosynthetic electron flow in transgenic tomato leaves with suppressed LeChrDi/c expression was 30-50% of their control, non-transgenic counterparts and was ascribed to lower PSI activity. Transgenic flowers with suppressed LeChrDi/c also accumulated up to 30% less carotenoids per unit protein as compared to control plants, indicating an interrelationship between PAPs and floral-specific carotenoid accumulation in chromoplasts. We suggest that CHRD's role in the angiosperm reproductive unit may be a rather recent evolutionary development; its original function may have been to protect the plant under stress conditions by preserving plastid functionality.
AB - Studies on the carotenoid-overaccumulating structures in chromoplasts have led to the characterization of proteins termed plastid lipid-associated proteins (PAPs), involved in the sequestration of hydrophobic compounds. Here we characterize the PAP CHRD, which, based on sequence homology, belongs to a highly conserved group of proteins, YER057c/YjgF/UK114, involved in the regulation of basic and vital cellular processes in bacteria, yeast and animals. Two nuclear genes were characterized in tomato plants: one (LeChrDc) is constitutively expressed in various tissues and the other (LeChrDi) is induced by stress in leaves and is upregulated by developmental cues in floral tissues. Using RNAi and antisense approaches, we show their involvement in biologically significant processes such as photosynthesis. The quantum yield of photosynthetic electron flow in transgenic tomato leaves with suppressed LeChrDi/c expression was 30-50% of their control, non-transgenic counterparts and was ascribed to lower PSI activity. Transgenic flowers with suppressed LeChrDi/c also accumulated up to 30% less carotenoids per unit protein as compared to control plants, indicating an interrelationship between PAPs and floral-specific carotenoid accumulation in chromoplasts. We suggest that CHRD's role in the angiosperm reproductive unit may be a rather recent evolutionary development; its original function may have been to protect the plant under stress conditions by preserving plastid functionality.
KW - Chloroplast
KW - Chromoplasts
KW - Plastid
KW - Stress
KW - Tomato
KW - YjgF protein
UR - http://www.scopus.com/inward/record.url?scp=33751015772&partnerID=8YFLogxK
U2 - 10.1007/s00425-006-0332-y
DO - 10.1007/s00425-006-0332-y
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C2 - 16845531
AN - SCOPUS:33751015772
SN - 0032-0935
VL - 225
SP - 89
EP - 102
JO - Planta
JF - Planta
IS - 1
ER -