Biology subjects

Liew, L. C.

Publications and source records attributed to Liew, L. C..

4 recordsLinked to original sources

bioRxiv2026

Developmental and regulatory logic of cannabis glandular trichomes resolved by single cell multiomics

Glandular trichomes of Cannabis sativa produce specialised metabolites including cannabinoids and terpenes, yet the cellular basis of trichome development and metabolic specialisation remains unresolved. Here we reconstruct the glandular trichome lineage within the C. sativa inflorescence using single-cell transcriptomics and chromatin accessibility profiling. We identify a continuous developmental trajectory from the protoderm, linking bulbous, sessile, and capitate-stalked trichomes, indicating that these morphologies represent sequential stages rather than distinct trichome types. We further identify a previously undescribed neck cell that shares a developmental origin with secretory disc cells before lineage bifurcation. Integration of chromatin accessibility with transcription factor (TF) binding reveals cell state specific regulatory programs coordinating neck cell development and specialised metabolism, redox homeostasis, and secretion in mature secretory disc cells. Methyl jasmonate elicitation induces extensive transcriptional and chromatin landscape reprogramming in mature secretory disc cells and transient repression of specialised metabolic pathways. Together, these findings provide a cell-resolved regulatory framework for glandular trichome development and function, revising prevailing models of trichome identity, maturation and defence associated metabolic regulation.

plant biology↗

bioRxiv2023

Spatially Resolved Transcriptomic Analysis of the Germinating Barley Grain

Seeds, which provide a major source of calories for humans, are a unique stage of a flowering plant s lifecycle. During seed germination the embryo reactivates rapidly and goes through major developmental transitions to become a seedling. This requires extensive and complex spatiotemporal coordination of cell and tissue activity. Existing gene expression profiling methods, such as laser capture microdissection followed by RNA-seq and single-cell RNA-seq, suffer from either low throughput or the loss of spatial information about the cells analysed. Spatial transcriptomics methods couple high throughput analysis of gene expression simultaneously with the ability to record the spatial location of each individual region analysed. We developed a spatial transcriptomics workflow for germinating barley grain to better understand the spatiotemporal control of gene expression within individual seed cell types. More than 14,000 genes were differentially regulated across 0, 1, 3, 6 and 24 hours after imbibition. This approach enabled us to observe that many functional categories displayed specific spatial expression patterns that could be resolved at a sub-tissue level. Individual aquaporin gene family members, important for water and ion transport, had specific spatial expression patterns over time, as well as genes related to cell wall modification, membrane transport and transcription factors. Using spatial autocorrelation algorithms, we were able to identify auxin transport genes that had increasingly focused expression within subdomains of the embryo over germination time, suggestive of a role in establishment of the embryo axis. Together, our data provides an unprecedented spatially resolved cellular map for barley grain germination and specific genes to target for functional genomics to define cellular restricted processes in tissues during germination. The data can be viewed at https://spatial.latrobe.edu.au/.

plant biology↗

bioRxiv2023

Establishment of cell transcriptional identity during seed germination

Germination involves highly dynamic transcriptional programs as the cells of seeds reactivate and express the functions necessary to establish in the environment. Individual cell types have distinct roles within the embryo, so must therefore have cell-type specific gene expression and gene regulatory networks. We can better understand how the functions of different cell types are established and contribute to the embryo by determining how cell-type specific transcription begins and changes through germination. Here we describe a temporal analysis of the germinating Arabidopsis embryo at single-cell resolution. We define the highly dynamic cell-type specific patterns of gene expression and how these relate to changing cellular function as germination progresses. Underlying these are unique gene regulatory networks and transcription factor activity. We unexpectedly discover that most embryo cells transition through the same initial transcriptional state early in germination, after which cell-type specific gene expression is established. Furthermore, our analyses support previous findings that the earliest events leading to the induction of embryo growth take place in the vasculature. Overall, our study constitutes a general framework to characterise Arabidopsis cell states through embryo growth, allowing investigation of different genotypes and other plant species whose seed strategies may differ.

plant biology↗

bioRxiv2021

Generation of human chambered cardiac organoids from pluripotent stem cells for improved modelling of cardiovascular diseases

Recent progress on murine and human cardiac organoids have provided understanding to the developmental processes of the heart. However, there is still an unfulfilled need for improved modelling of cardiovascular diseases using human cardiac organoids. Herein, we report successful generation of intrinsically formed human chambered cardiac organoids (CCO) and highlight its utility in modelling disease. Single cell transcriptomic profiling of CCOs showed appropriate cardiovascular cell type composition exhibiting improved maturation. Functionally, CCOs recapitulated clinical cardiac hypertrophy by exhibiting thickened chamber walls, reduced ejection fractions, increased myofibrillar disarray and tachycardia. Therefore, CCOs improve current capabilities of disease modelling as an in vitro model bridging the gap to in vivo models, with the ability to assess functional parameters that previously can only be achieved in animal systems. One sentence summaryModelling cardiac hypertrophy using chambered cardiac organoids derived from human pluripotent stem cells.

cell biology↗