Journal Article

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

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

2021

Overview

Background The developmental gradient in monocot leaves has been exploited to uncover leaf developmental gene expression programs 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.

• Publisher: BioMed Central,Springer Nature B.V,BMC
• Subject: algorithms / Animal Genetics and Genomics / biogenesis / Bioinformatics / Biomedical and Life Sciences / Biosynthesis / Cell cycle / Cell differentiation / Cell proliferation / Cell Proliferation - genetics / Chloroplast / chloroplast genes / Chloroplasts / Chloroplasts - genetics / Developmental stages / Evolutionary Biology / Gene expression / Gene Expression Profiling / Gene Expression Regulation, Plant / Gene Regulatory Networks / Genome, Plastid / Genomes / Human Genetics / Leaf development / Leaves / Life Sciences / Liliopsida / meristems / Mesophyll / Microbial Genetics and Genomics / Microscopy / Morphology / Photosynthesis / Photosynthesis - genetics / Plant Genetics and Genomics / Plant Leaves - cytology / Plant Leaves - genetics / Plant Leaves - growth & development / Plant Proteins - metabolism / Plastid / Principal Component Analysis / Principal components analysis / Protein Biosynthesis - genetics / quantitative analysis / Transcription / transcription (genetics) / transcriptome / Transcriptomes / transcriptomics / Triticum - cytology / Triticum - genetics / Wheat