Deciphering the dynamic regulatory networks of poplar leaf development: A comprehensive transcriptomic and miRNA analysis
image: Sample collection and cluster analysis of the poplar leaf transcriptome and miRNAs a Fifteen leaf positions were collected for RNA-seq, and seven leaf positions were collected for small RNA sequencing. b 3D PCA of the transcriptomes of all 15 sampling points. c–e Phenotype (photosynthesis rate, leaf area, content of chlorophyll) of poplar leaf at the Y–M stage and M–S stage.
Credit: Horticulture Research
Poplar trees are crucial for afforestation and urban greening, and their leaf development stages affect biomass accumulation. Despite the known physiological changes from young to senescent leaves, the transcriptional regulatory network in poplars is poorly understood. Research has explored the roles of miRNAs and transcription factors in leaf development, but studies primarily focus on individual gene functions. The dynamic regulation of these processes throughout the leaf life cycle, particularly in poplars, remains largely unexplored.
In September 2023, Horticulture Research published a research entitled by “Spatiotemporal miRNA and transcriptomic network dynamically regulate the developmental and senescence processes of poplar leaves”.
In this study, researchers used principal component analysis to classify poplar leaves with different leaf positions into two stages: developmental maturity (the stage of maximum photosynthetic capacity); and the stage in which the photosynthetic capacity begins to decline and gradually turns into senescence, and found that the two major developmental stages had distinct gene expression patterns and phenotypic changes, such as variations in photosynthesis, leaf area, and chlorophyll content. Functional enrichment and KEGG pathway analysis further categorized these genes into pathways integral to plant hormone signal transduction, chlorophyll metabolism, and photosynthesis. Moreover, these two stages were further subdivided into five intervals by gene expression clustering analysis: young leaves, the stage of cell genesis and functional differentiation (L1); young leaves, the stage of development and initial formation of photosynthetic capacity (L3-L7); the stage of maximum photosynthetic capacity of functional leaves (L9-L13); the stage of decline of photosynthetic capacity of functional leaves (L15-L27); and the stage of senescent leaves (L29).
A high-resolution spatiotemporal transcriptional regulatory network was constructed through co-expression gene network analysis of regulatory genes, revealing the key modules and transcription factors regulating leaf growth and development, as well as senescence. Spatiotemporal transcriptomic data of poplar leaves revealed dynamic changes of genes and miRNAs during leaf development and identified several core regulators of leaf development, such as GRF5 and MYB5.
In conclusion, this research offers a detailed view of the regulatory networks governing leaf development in Populus, from gene expression patterns to the roles of miRNAs and transcription factors. It provides a foundation for understanding the molecular mechanisms of leaf growth, development, and senescence, contributing valuable insights for future studies aimed at enhancing biomass accumulation and improving photosynthetic efficiency in poplar trees.
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References
Authors
Kang Du1, Shenxiu Jiang1, Hao Chen1, Yufei Xia1, Ruihua Guo1, Aoyu Ling1, Ting Liao2, Wenqi Wu3 and Xiangyang Kang1,*
Affiliations
1State Key Laboratory of Tree Genetics and Breeding, National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
2Institute of Forestry and Botany, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100093, China
3Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
About Xiangyang Kang
Professor, College of Biological Sciences and Biotechnology, Beijing Forestry University. His research interests include:
1. Polyploid breeding theory and technology of forest trees;
2. Selection and breeding of good forest species;
3.Forest cytogenetics;
4.Biotechnology-assisted breeding.