Transcriptomic analyses to summarize gene expression patterns that occur during leaf initiation of Chinese cabbage

Area of Science:

• Plant Molecular Biology
• Developmental Genetics
• Brassica Genomics

Background:

• Chinese cabbage leaf development is crucial for its characteristic leafy head structure.
• Leaf adaxial/abaxial polarity and primordia formation are fundamental to plant architecture.
• Genetic complexity in *Brassica* species, due to polyploidy, complicates the study of leaf development.

Purpose of the Study:

• To investigate the molecular genetic mechanisms underlying leaf primordia development in Chinese cabbage.
• To identify genes and pathways involved in establishing leaf polarity and regulating leaf expansion.
• To provide a foundation for understanding the genetic basis of leafy head formation.

Main Methods:

• Laser dissection of Chinese cabbage leaf primordia and shoot apical meristem (SAM).
• Comparative transcriptome analysis of adaxial and abaxial leaf sides, and the SAM.
• Assessment of gene expression gradients along expanded leaf blades.

Main Results:

• Identified differentially expressed genes, including those in hormone pathways and transcription factors, during leaf primordia development.
• Revealed gene expression patterns associated with adaxial/abaxial polarity establishment.
• Uncovered regulatory links between the SAM, leaf primordia, and expanding rosette leaves.

Conclusions:

• The study provides a valuable catalogue of genes involved in Chinese cabbage leaf development.
• These findings offer insights into the genetic regulation of leaf form and leafy head formation.
• This work serves as a starting point for further unraveling the genetic control of plant architecture in *Brassica*.