TY - JOUR
T1 - Rice CYO1, an ortholog of Arabidopsis thaliana cotyledon chloroplast biogenesis factor AtCYO1, is expressed in leaves and involved in photosynthetic performance
AU - Tominaga, Jun
AU - Mizutani, Haruka
AU - Horikawa, Daisuke
AU - Nakahara, Yasutoshi
AU - Takami, Tsuneaki
AU - Sakamoto, Wataru
AU - Sakamoto, Atsushi
AU - Shimada, Hiroshi
N1 - Funding Information:
We are grateful to Dr. Shunichi Takahashi (National Institute for Basic Biology, Japan) and Dr. Masaki Shimamura (Hiroshima University, Japan) for helpful discussions. We thank Dr. Daisuke Miki and Dr. Ko Shimamoto (Nara Insitute of Science and Technology, Japan) for the gift of pANDA vector. This work was supported in part by a JSPS KAKENHI Grant (number 26450081 , H.S.), by grants from the Advanced Low Carbon Technology Research and Development Program of the Japan Science and Technology Agency (H.S.), and by the Ministry of Education, Culture, Sports and Technology (MEXT) as part of a Joint Research Program implemented as the Institute of Plant Science and Resources, Okayama University, Japan.
PY - 2016/12/1
Y1 - 2016/12/1
N2 - In the dicotyledonous plant Arabidopsis thaliana, the cotyledon chloroplast biogenesis factor AtCYO1 is crucial for the biogenesis of cotyledon chloroplasts. Arabidopsis mutants lacking AtCYO1 have pale cotyledons but develop normal mature leaves. In the monocotyledonous plant Oryza sativa, the gene OsCYO1 has high sequence identity to AtCYO1, but its function is unknown. We examined the role of OsCYO1 in O. sativa. We first confirmed that transformation with OsCYO1 could recover the phenotype of the Arabidopsis cyo1 mutant. Similar to AtCYO1, recombinant OsCYO1 has protein disulfide reductase (PDR) activity, which increased as a function of dieosin glutathione disulfide concentration with an apparent Km of 3.2 μM and Kcat of 0.53 min−1. The PDR activity was reduced when NADPH or NADH was used as an electron donor; however, PDR activity was observed with OsCYO1 and glutathione, suggesting that glutathione may serve as a reducing agent for OsCYO1 in vivo. In O. sativa, the OsCYO1 transcript level was higher in leaves compared with the coleoptile, which is the first leaf-like organ that forms during rice embryogenesis. Many OsCYO1 mutant lines defective in RNA interference had green leaves, however, three mutant lines had not only albino coleoptile but also albino leaves. Those having green leaves reduced photosynthetic performance in leaves. Our results demonstrate that OsCYO1 is enzymatically equivalent to AtCYO1 but that the physiological role of OsCYO1 in monocotyledonous plants may differ from that of AtCYO1 in dicotyledonous plants.
AB - In the dicotyledonous plant Arabidopsis thaliana, the cotyledon chloroplast biogenesis factor AtCYO1 is crucial for the biogenesis of cotyledon chloroplasts. Arabidopsis mutants lacking AtCYO1 have pale cotyledons but develop normal mature leaves. In the monocotyledonous plant Oryza sativa, the gene OsCYO1 has high sequence identity to AtCYO1, but its function is unknown. We examined the role of OsCYO1 in O. sativa. We first confirmed that transformation with OsCYO1 could recover the phenotype of the Arabidopsis cyo1 mutant. Similar to AtCYO1, recombinant OsCYO1 has protein disulfide reductase (PDR) activity, which increased as a function of dieosin glutathione disulfide concentration with an apparent Km of 3.2 μM and Kcat of 0.53 min−1. The PDR activity was reduced when NADPH or NADH was used as an electron donor; however, PDR activity was observed with OsCYO1 and glutathione, suggesting that glutathione may serve as a reducing agent for OsCYO1 in vivo. In O. sativa, the OsCYO1 transcript level was higher in leaves compared with the coleoptile, which is the first leaf-like organ that forms during rice embryogenesis. Many OsCYO1 mutant lines defective in RNA interference had green leaves, however, three mutant lines had not only albino coleoptile but also albino leaves. Those having green leaves reduced photosynthetic performance in leaves. Our results demonstrate that OsCYO1 is enzymatically equivalent to AtCYO1 but that the physiological role of OsCYO1 in monocotyledonous plants may differ from that of AtCYO1 in dicotyledonous plants.
KW - CYO1
KW - Coleoptile
KW - Cotyledon
KW - Leaf
KW - Oryza sativa
KW - Pulse amplitude modulation
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U2 - 10.1016/j.jplph.2016.10.005
DO - 10.1016/j.jplph.2016.10.005
M3 - Article
C2 - 27835768
AN - SCOPUS:84994613447
VL - 207
SP - 78
EP - 83
JO - Journal of Plant Physiology
JF - Journal of Plant Physiology
SN - 0176-1617
ER -