Single-cell transcriptomics unveils xylem cell development and evolution

Area of Science:

• Plant biology
• Evolutionary developmental biology
• Transcriptomics

Background:

• Xylem is crucial for plant lateral growth, comprising ray and fusiform cells.
• Fusiform cells differentiate into vessel elements and libriform fibers in angiosperms, or function as tracheids in gymnosperms.
• Developmental programs and evolutionary relationships of xylem cell types are poorly understood.

Purpose of the Study:

• To determine the developmental lineages of ray and fusiform cells in stem-differentiating xylem.
• To analyze these lineages across four divergent woody angiosperms.
• To understand the evolutionary conservation and variation of xylem cell development.

Main Methods:

• Single-cell transcriptomic profiling
• Laser capture microdissection transcriptomic profiling
• Cross-species comparative analyses of transcriptomic data

Main Results:

• Ray cell lineages are highly conserved across angiosperms.
• Fusiform cell lineages show significant variation across angiosperms.
• Basal angiosperms and core eudicots exhibit distinct fusiform lineages.
• Tracheids in a basal eudicot show transcriptomic similarity to vessel elements.

Conclusions:

• An evo-devo framework for xylem cell lineage formation is established.
• This framework spans over 100 million years of plant evolutionary history.
• The study provides a comprehensive understanding of xylem cell development and evolution.