¹ O ₂ -mediated retrograde signaling during late embryogenesis predetermines plastid differentiation in seedlings by recruiting abscisic acid

Abstract

Plastid development in seedlings of Arabidopsis thaliana is affected by the transfer of 1 O2-mediated retrograde signals from the plastid to the nucleus and changes in nuclear gene expression during late embryogenesis. The potential impact of these mechanisms on plastid differentiation is maintained throughout seed dormancy and becomes effective only after seed germination. Inactivation of the 2 nuclear-encoded plastid proteins EXECUTER1 and EXECUTER2 blocks 1 O2-mediated retrograde signaling before the onset of dormancy and impairs normal plastid formation in germinating seeds. This long-term effect of 1 O2 retrograde signaling depends on the recruitment of abscisic acid (ABA) during seedling development. Unexpectedly, ABA acts as a positive regulator of plastid formation in etiolated and light-grown seedlings.

Reactive oxygen species generation and signaling in plants

“…79 Inactivation of executer proteins blocks the 1 O 2 -mediated signaling from the chloroplast to the nucleus that affects the normal plastid development in germinating seeds. 80 Coll et al 81 82 Apart from Pchlide, early intermediates i.e., coproporphyrin also acts as a photosensitizer. [83][84][85] The antisense coproporphyrinogen oxidase (that converts coproporphyrinogen III to protoporphyrinogen IX) in tobacco plants, have an excessive amount of coproporphyrin.…”

Molecular components of stress-responsive plastid retrograde signaling networks and their involvement in ammonium stress

“…Similarly, ABA signaling has also been found to be involved in the H 2 O 2 -dependent plastid signal that activates high-light responsive gene expression in leaves 43 and to be recruited by an 1 O 2 -dependent plastid signal during late embryogenesis where it affects plastid differentiation by reactivating relevant nuclear-encoded genes. 44 Therefore, interactions between plastid retrograde signaling and ABA signaling may be a common occurrence during stress responses. In an earlier review, a hypothesis was advanced to describe the interaction between plastid retrograde signaling and ABA signaling in the context of high light stress.…”

Genetic Dissection of Chloroplast Biogenesis and Development: An Overview

“…Of particular interest in the context of this article are signals related to biogenic control, that is, those that affect nuclear transcription during plastid development (Pogson et al, 2008). The PSII-associated proteins, EXECUTER1 and EXECUTER2, mediate singlet oxygen signaling pathways (Kim et al, 2009a). Interestingly, the double mutant ex1ex2 exhibit white cotyledon regions that contain undifferentiated plastids that resemble proplastids.…”