Among the major phytohormones, the cytokinin exhibits unique features for its ability
to positively affect the developmental status of plastids. Even early on in its research,
cytokinins were known to promote plastid differentiation and to reduce the loss of
chlorophyll in detached leaves. Since the discovery of the components of cytokinin
perception and primary signaling, the genes involved in photosynthesis and plastid
differentiation have been identified as those directly targeted by type-B response
regulators. Furthermore, cytokinins are known to modulate versatile cellular processes
such as promoting the division and differentiation of cells and, in concert with auxin,
initiating the de novo formation of shoot apical meristem (SAM) in tissue cultures.
Yet how cytokinins precisely participate in such diverse cellular phenomena, and
how the associated cellular processes are coordinated as a whole, remains unclear.
A plausible presumption that would account for the coordinated gene expression is
the tight and reciprocal communication between the nucleus and plastid. The fact
that cytokinins affect plastid developmental status via gene expression in both the
nucleus and plastid is interpreted here to suggest that cytokinin functions as an
initiator of anterograde (nucleus-to-plastid) signaling. Based on this viewpoint, we first
summarize the physiological relevance of cytokinins to the coordination of plastid
differentiation with de novo shoot organogenesis in tissue culture systems. Next, the role
of endogenous cytokinins in influencing plastid differentiation within the SAM of intact
plants is discussed. Finally, a presumed plastid-derived signal in response to cytokinins
for coupled nuclear gene expression is proposed.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:84427 |
| Date | 30 March 2023 |
| Creators | Ikeda, Yoshihisa, Zalabák, David, Kubalová, Ivona, Králová, Michaela, Brenner, Wolfram G., Aida, Mitsuhiro |
| Publisher | Frontiers Research Foundation |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 1664-462X, 641257 |
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