توضیحات
ABSTRACT
Plant cells plastically change their functions according to the environment. Although Arabidopsis roots are heterotrophic organs, they increase photosynthetic capacity after shoot removal. Transcription factors regulating chloroplast development are involved in this response downstream of positive cytokinin and negative auxin regulation. To dissect the crosstalk of these regulators after shoot removal, we analyzed photosynthetic parameters in roots with chloroplast development enhanced by shoot removal, overexpression of transcription factors, or hormonal treatment. Our data suggest that shoot removal improves electron transfer downstream of PSII in roots, with a decrease in nonregulated energy dissipation. Cytokinin, auxin, and transcription factors affect the photosynthetic capacity of roots in a highly complex manner. Overexpression of two different types of transcription factors (GOLDEN 2-LIKE 1 and class-B GATAs) synergistically increased root chlorophyll content while maintaining high photosynthetic efficiency. Our data demonstrate the flexible regulation of the photosynthetic machinery by hormone signaling and downstream transcription factors.
INTRODUCTION
In seed plants, plastids differentiate into various forms with their respective functions to fulfill the diverse roles of host cells (Jarvis and López-Juez 2013). Development of chloroplasts from other plastids, such as proplastids and etioplasts, is one of the most important cellular processes for plants to establish photoautotrophic growth. Photosynthesis allows plants to grow depending on light energy but with simultaneous threat of photooxidative damage to cells. Therefore, plants should strictly regulate development and the functionality of chloroplasts in coordination with the developmental and functional states of cells and tissues and in response to growth environments. However, the coordination mechanisms of cellular and plastid development remain largely elusive. In general, roots develop underground as heterotrophic organs with dependence on leaves for their energy and carbon source. In Arabidopsis thaliana, chloroplast development in roots is strongly suppressed in part via the auxin-signaling pathway, even when the roots are fully illuminated on transparent agar plates (Kobayashi et al. 2012). Chlorophyll (Chl) only slightly accumulates in illuminated Arabidopsis roots, particularly around the root– hypocotyl junction. Illuminated roots can perform photosynthetic electron transport but with lower photochemical efficiency and larger photoprotective nonphotochemical quenching (NPQ) than leaves (Kobayashi et al.
Year: ۲۰۱8
Publisher : ELSEVIER
By : A. OHNISHI, H. WADA, and K. KOBAYASHI
File Information: English Language/ 12 Page / size: 2.49 MB
سال : ۱۳۹6
ناشر : ELSEVIER
کاری از : A. OHNISHI، H. WADA، و K. KOBAYASHI
اطلاعات فایل : زبان انگلیسی / 12 صفحه / حجم : MB 2.49
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