New Constitutively Active Phytochromes Exhibit Light-Independent Signaling Activity.
Plant phytochromes are photoreceptors that mediate a variety of photomorphogenic responses. There are two spectral photoisomers, the red light-absorbing Pr and far-red light-absorbing Pfr forms, and the photoreversible transformation between the two forms is important for the functioning of phytochromes. In this study, we isolated a Tyr-268-to-Val mutant of Avena sativa phytochrome A (AsYVA) that displayed little photoconversion. Interestingly, transgenic plants of AsYVA showed light-independent phytochrome signaling with a constitutive photomorphogenic (cop) phenotype that is characterized by shortened hypocotyls and open cotyledons in the dark. In addition, the corresponding Tyr-303-to-Val mutant of Arabidopsis (Arabidopsis thaliana) phytochrome B (AtYVB) exhibited nuclear localization and interaction with phytochrome-interacting factor 3 (PIF3) independently of light, conferring a constitutive photomorphogenic development to its transgenic plants, which is comparable to the first constitutively active version of phytochrome B (YHB; Tyr-276-to-His mutant). We also found that chromophore ligation was required for the light-independent interaction of AtYVB with PIF3. Moreover, we demonstrated that AtYVB did not exhibit phytochrome B activity when it was localized in the cytosol by fusion with the nuclear export signal and that AsYVA exhibited the full activity of phytochrome A when localized in the nucleus by fusion with the nuclear localization signal. Furthermore, the corresponding Tyr-269-to-Val mutant of Arabidopsis phytochrome A (AtYVA) exhibited similar cop phenotypes in transgenic plants to AsYVA. Collectively, these results suggest that the conserved Tyr residues in the chromophore-binding pocket play an important role during the Pr-to-Pfr photoconversion of phytochromes, providing new constitutively active alleles of phytochromes by the Tyr-to-Val mutation.
Department of Biotechnology and Kumho Life Science Laboratory (A.-R.J., S.-S.L., Y.-J.H., A.-Y.S., M.-G.K., Y.S.K., J.-I.K.) and College of Veterinary Medicine (T.A.), Chonnam National University, Gwangju 61186, Republic of Korea;Division of Applied Life Science (BK21 Plus Program), Systems and Synthetic Agrobiotech Center, Plant Molecular Biology and Biotechnology Research Center, Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea (A.B., K.W.L.); andGraduate School of Science, Kyoto University, Kyoto 606-8502, Japan (A.N.).
A-Reum
AR
Jeong
Department of Biotechnology and Kumho Life Science Laboratory (A.-R.J., S.-S.L., Y.-J.H., A.-Y.S., M.-G.K., Y.S.K., J.-I.K.) and College of Veterinary Medicine (T.A.), Chonnam National University, Gwangju 61186, Republic of Korea;Division of Applied Life Science (BK21 Plus Program), Systems and Synthetic Agrobiotech Center, Plant Molecular Biology and Biotechnology Research Center, Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea (A.B., K.W.L.); andGraduate School of Science, Kyoto University, Kyoto 606-8502, Japan (A.N.).
Si-Seok
SS
Lee
Department of Biotechnology and Kumho Life Science Laboratory (A.-R.J., S.-S.L., Y.-J.H., A.-Y.S., M.-G.K., Y.S.K., J.-I.K.) and College of Veterinary Medicine (T.A.), Chonnam National University, Gwangju 61186, Republic of Korea;Division of Applied Life Science (BK21 Plus Program), Systems and Synthetic Agrobiotech Center, Plant Molecular Biology and Biotechnology Research Center, Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea (A.B., K.W.L.); andGraduate School of Science, Kyoto University, Kyoto 606-8502, Japan (A.N.).
Yun-Jeong
YJ
Han
Department of Biotechnology and Kumho Life Science Laboratory (A.-R.J., S.-S.L., Y.-J.H., A.-Y.S., M.-G.K., Y.S.K., J.-I.K.) and College of Veterinary Medicine (T.A.), Chonnam National University, Gwangju 61186, Republic of Korea;Division of Applied Life Science (BK21 Plus Program), Systems and Synthetic Agrobiotech Center, Plant Molecular Biology and Biotechnology Research Center, Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea (A.B., K.W.L.); andGraduate School of Science, Kyoto University, Kyoto 606-8502, Japan (A.N.).
Ah-Young
AY
Shin
Department of Biotechnology and Kumho Life Science Laboratory (A.-R.J., S.-S.L., Y.-J.H., A.-Y.S., M.-G.K., Y.S.K., J.-I.K.) and College of Veterinary Medicine (T.A.), Chonnam National University, Gwangju 61186, Republic of Korea;Division of Applied Life Science (BK21 Plus Program), Systems and Synthetic Agrobiotech Center, Plant Molecular Biology and Biotechnology Research Center, Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea (A.B., K.W.L.); andGraduate School of Science, Kyoto University, Kyoto 606-8502, Japan (A.N.).
Ayoung
A
Baek
Department of Biotechnology and Kumho Life Science Laboratory (A.-R.J., S.-S.L., Y.-J.H., A.-Y.S., M.-G.K., Y.S.K., J.-I.K.) and College of Veterinary Medicine (T.A.), Chonnam National University, Gwangju 61186, Republic of Korea;Division of Applied Life Science (BK21 Plus Program), Systems and Synthetic Agrobiotech Center, Plant Molecular Biology and Biotechnology Research Center, Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea (A.B., K.W.L.); andGraduate School of Science, Kyoto University, Kyoto 606-8502, Japan (A.N.).
Taeho
T
Ahn
Department of Biotechnology and Kumho Life Science Laboratory (A.-R.J., S.-S.L., Y.-J.H., A.-Y.S., M.-G.K., Y.S.K., J.-I.K.) and College of Veterinary Medicine (T.A.), Chonnam National University, Gwangju 61186, Republic of Korea;Division of Applied Life Science (BK21 Plus Program), Systems and Synthetic Agrobiotech Center, Plant Molecular Biology and Biotechnology Research Center, Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea (A.B., K.W.L.); andGraduate School of Science, Kyoto University, Kyoto 606-8502, Japan (A.N.).
Min-Gon
MG
Kim
Department of Biotechnology and Kumho Life Science Laboratory (A.-R.J., S.-S.L., Y.-J.H., A.-Y.S., M.-G.K., Y.S.K., J.-I.K.) and College of Veterinary Medicine (T.A.), Chonnam National University, Gwangju 61186, Republic of Korea;Division of Applied Life Science (BK21 Plus Program), Systems and Synthetic Agrobiotech Center, Plant Molecular Biology and Biotechnology Research Center, Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea (A.B., K.W.L.); andGraduate School of Science, Kyoto University, Kyoto 606-8502, Japan (A.N.).
Young Soon
YS
Kim
Department of Biotechnology and Kumho Life Science Laboratory (A.-R.J., S.-S.L., Y.-J.H., A.-Y.S., M.-G.K., Y.S.K., J.-I.K.) and College of Veterinary Medicine (T.A.), Chonnam National University, Gwangju 61186, Republic of Korea;Division of Applied Life Science (BK21 Plus Program), Systems and Synthetic Agrobiotech Center, Plant Molecular Biology and Biotechnology Research Center, Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea (A.B., K.W.L.); andGraduate School of Science, Kyoto University, Kyoto 606-8502, Japan (A.N.).
Keun Woo
KW
Lee
Department of Biotechnology and Kumho Life Science Laboratory (A.-R.J., S.-S.L., Y.-J.H., A.-Y.S., M.-G.K., Y.S.K., J.-I.K.) and College of Veterinary Medicine (T.A.), Chonnam National University, Gwangju 61186, Republic of Korea;Division of Applied Life Science (BK21 Plus Program), Systems and Synthetic Agrobiotech Center, Plant Molecular Biology and Biotechnology Research Center, Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea (A.B., K.W.L.); andGraduate School of Science, Kyoto University, Kyoto 606-8502, Japan (A.N.).
Akira
A
Nagatani
Department of Biotechnology and Kumho Life Science Laboratory (A.-R.J., S.-S.L., Y.-J.H., A.-Y.S., M.-G.K., Y.S.K., J.-I.K.) and College of Veterinary Medicine (T.A.), Chonnam National University, Gwangju 61186, Republic of Korea;Division of Applied Life Science (BK21 Plus Program), Systems and Synthetic Agrobiotech Center, Plant Molecular Biology and Biotechnology Research Center, Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Republic of Korea (A.B., K.W.L.); andGraduate School of Science, Kyoto University, Kyoto 606-8502, Japan (A.N.) kimji@jnu.ac.kr.
Jeong-Il
0000-0003-4177-4048
JI
Kim
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D055537:Light Signal Transduction; D009154:Mutation / Q000235:genetics; D049790:Nuclear Export Signals; D019913:Nuclear Localization Signals / Q000378:metabolism; D010641:Phenotype; D010834:Phytochrome / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011485:Protein Binding; D013347:Subcellular Fractions / Q000378:metabolism
D049790:Nuclear Export Signals; D019913:Nuclear Localization Signals; D010834:Phytochrome