Temporal dynamics of genetic architecture governing leaf development in Populus

An Arabidopsis single-nucleus atlas decodes leaf senescence and nutrient allocation

With rapid advancements in single-cell RNA sequencing (scRNA-seq) technologies, exploration of the systemic coordination of critical physiological processes has entered a new era. Here, we generated a comprehensive Arabidopsis single-nucleus transcriptomic atlas using over 1 million nuclei from 20 tissues encompassing multiple developmental stages. Our analyses identified cell types that have not been characterized in previous single-protoplast studies and revealed cell-type conservation and specificity across different organs. Through time-resolved sampling, we revealed highly coordinated onset and progression of senescence among the major leaf cell types. We originally formulated two molecular indexes to quantify the aging state of leaf cells at single-cell resolution. Additionally, facilitated by weighted gene co-expression network analysis, we identified hundreds of promising hub genes that may integratively regulate leaf senescence. Inspired by the functional validation of identified hub genes, we built a systemic scenario of carbon and nitrogen allocation among different cell types from source leaves to sink organs.

Transcription factor PagERF110 inhibits leaf development by direct regulating PagHB16 in poplar

Ethylene-responsive factor (ERF) family genes are crucial for plant growth and development. This study analyzed the functional role of the PagERF110 gene in leaf development of Populus alba×P. glandulosa. PagERF110 contains the AP2 conserved domain and exhibits transcriptional activation activity at its C-terminus. Overexpression of PagERF110 in transgenic poplar trees resulted in reduced leaf size, leaf area, and vein xylem thickness. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) experiments confirmed that PagERF110 interacts with PagACD32.1. Transcriptome sequencing revealed that PagERF110 regulates the expression of key genes involved in leaf development. Furthermore, yeast one-hybrid (Y1H) assays, GUS staining, and ChIP experiments collectively confirmed that PagERF110 targets the expression of PagHB16. In summation, our findings demonstrate that PagERF110 functions as a negative regulator in poplar leaf development.

Genetic Evidence of SpGH9A3 in Leaf Morphology Variation of Spathiphyllum 'Mojo'

Leaves play a crucial role as ornamental organs in Spathiphyllum, exhibiting distinct differences across various Spathiphyllum varieties. Leaf development is intricately linked to processes of cell proliferation and expansion, with cell morphology often regulated by plant cell walls, primarily composed of cellulose. Alterations in cellulose content can impact cell morphology, subsequently influencing the overall shape of plant organs. Although cellulases have been shown to affect cellulose levels in plant cells, genetic evidence linking them to the regulation of leaf shape remains limited. This study took the leaves of Spathiphyllum 'Mojo' and its somatic variants as the research objects. We screened four cellulase gene family members from the transcriptome and then measured the leaf cellulose content, cellulase activity, and expression levels of cellulase-related genes. Correlation analysis pinpointed the gene SpGH9A3 as closely associated with leaf shape variations in the mutant. Green fluorescent fusion protein assays revealed that the SpGH9A3 protein was localized to the cell membrane. Notably, the expression of the SpGH9A3 gene in mutant leaves peaked during the early spread stage, resulting in smaller overall leaf size and reduced cellulose content upon overexpression in Arabidopsis.