Cellular and transcriptomic analyses reveal two-staged chloroplast biogenesis underpinning photosynthesis build-up in the wheat leaf

Naresh Loudya, Priyanka Mishra, Kotaro Takahagi, Yukiko Uehara-Yamaguchi, Komaki Inoue, Laszlo Bogre, Keiichi Mochida, Enrique Lopez Juez

Research output: Contribution to journalArticlepeer-review

Abstract

Background: The developmental gradient in monocot leaves has been exploited to uncover leaf developmental gene expression programmes and chloroplast biogenesis processes. However, the relationship between the two is barely understood, which limits the value of transcriptome data to understand the process of chloroplast development.
Results: Taking advantage of the developmental gradient in the bread wheat leaf, we provide a simultaneous quantitative analysis for the development of mesophyll cells and of chloroplasts as a cellular compartment. This allows us to generate the first biologically-informed gene expression map of this leaf, with the entire developmental gradient from meristematic to fully differentiated cells captured. We show that the first phase of plastid development begins with organelle proliferation, which extends well beyond cell proliferation, and continues with the establishment and then the build-up of the plastid genetic machinery. The second phase is marked by the development of photosynthetic chloroplasts which occupy the available cellular space. Using a network reconstruction algorithm, we predict that known chloroplast gene expression regulators are differentially involved across those developmental stages.
Conclusions: Our analysis generates both the first wheat leaf transcriptional map and one of the most comprehensive descriptions to date of the developmental history of chloroplasts in higher plants. It reveals functionally-distinct plastid and chloroplast development stages, identifies processes occurring in each of them, and highlights our very limited knowledge of the earliest drivers of plastid biogenesis, while providing a basis for their future identification.
Original languageEnglish
Article number151
JournalGenome Biology
Volume22
DOIs
Publication statusPublished - 11 May 2021

Keywords

  • wheat
  • plastid
  • chloroplast
  • leaf development

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