TY - JOUR
T1 - Effects of overexpression of the Rubisco small subunit gene under the control of the Rubisco activase promoter on Rubisco contents of rice leaves at different positions
AU - Kudo, Natsumi
AU - Mano, Kazuhisa
AU - Suganami, Mao
AU - Kondo, Eri
AU - Suzuki, Yuji
AU - Makino, Amane
N1 - Funding Information:
This study was supported by Core Research for Evolutional Science and Technology (Grant No. JPMJCR15O3 to YS) from the Japan Science and Technology Agency, Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (No. 18H02111 to YS and No. JP16H06379 to AM), JSPS Fellowships (No. 19J10653 to MS), and the Tohoku University’s Division for Interdisciplinary Advanced Research and Education to MS The authors would like to thank Editage for the English language editing.
Publisher Copyright:
© 2020, © 2020 Japanese Society of Soil Science and Plant Nutrition.
PY - 2020
Y1 - 2020
N2 - Photosynthetic activity is expected to be maintained during leaf senescence if the amount of Rubisco is maintained. As the mRNA level of the Rubisco gene decreases rapidly just before the stage of full expansion, its overexpression after full expansion would be effective. We previously found that the mRNA level of the Rubisco activase gene (RCA) is maintained during leaf senescence. In the present study, the Rubisco small subunit gene (RBCS) was overexpressed under the control of the promoter of RCA in rice. Although Rubisco content increased in the uppermost, fully expanded leaves of transgenic plants in comparison with that in wild-type plants, in the penultimate leaves it decreased to a level similar to that of the wild-type plants. In expanding leaves in transgenic plants, the mRNA levels of the transgene RBCS increased further, leading to increases in the mRNA levels of total RBCS and the Rubisco large subunit gene (RBCL). In the uppermost, fully expanded leaves and the penultimate fully expanded leaves, however, the mRNA levels of RBCS2 and total RBCS decreased drastically, and those of RBCL were similar to the wild-type levels. These results indicate that Rubisco content was not maintained during leaf senescence in the transgenic plants. One reason for this is that the expression of RBCS by the RCA promoter was weak in leaves at low positions. We discuss the possible reasons for this unexpected phenomenon.
AB - Photosynthetic activity is expected to be maintained during leaf senescence if the amount of Rubisco is maintained. As the mRNA level of the Rubisco gene decreases rapidly just before the stage of full expansion, its overexpression after full expansion would be effective. We previously found that the mRNA level of the Rubisco activase gene (RCA) is maintained during leaf senescence. In the present study, the Rubisco small subunit gene (RBCS) was overexpressed under the control of the promoter of RCA in rice. Although Rubisco content increased in the uppermost, fully expanded leaves of transgenic plants in comparison with that in wild-type plants, in the penultimate leaves it decreased to a level similar to that of the wild-type plants. In expanding leaves in transgenic plants, the mRNA levels of the transgene RBCS increased further, leading to increases in the mRNA levels of total RBCS and the Rubisco large subunit gene (RBCL). In the uppermost, fully expanded leaves and the penultimate fully expanded leaves, however, the mRNA levels of RBCS2 and total RBCS decreased drastically, and those of RBCL were similar to the wild-type levels. These results indicate that Rubisco content was not maintained during leaf senescence in the transgenic plants. One reason for this is that the expression of RBCS by the RCA promoter was weak in leaves at low positions. We discuss the possible reasons for this unexpected phenomenon.
KW - Leaf senescence
KW - Rubisco
KW - Rubisco activase promoter
KW - overexpression
KW - rice
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U2 - 10.1080/00380768.2020.1780898
DO - 10.1080/00380768.2020.1780898
M3 - Article
AN - SCOPUS:85088022942
SP - 569
EP - 578
JO - Soil Science and Plant Nutrition
JF - Soil Science and Plant Nutrition
SN - 0038-0768
ER -