Novel resources to investigate leaf plasmodesmata formation in C₃ and C₄ monocots

Area of Science:

• Plant Biology
• Cell Biology
• Photosynthesis Research

Background:

• Plasmodesmata (PD) are crucial nanochannels for plant cell-to-cell transport.
• C4 plants exhibit higher photosynthetic efficiency, partly due to increased PD at the mesophyll-bundle sheath interface.
• Understanding PD formation mechanisms is vital for improving crop productivity.

Purpose of the Study:

• To investigate the genetic mechanisms controlling plasmodesmata (PD) formation in C3 and C4 monocot leaves.
• To create a spatiotemporal atlas of leaf pit field density in rice (C3) and setaria (C4) without electron microscopy.
• To correlate PD density patterns with gene expression related to photosynthesis and PD function.

Main Methods:

• Generated stably transformed lines of Oryza sativa (rice) and Setaria viridis (setaria) with fluorescent protein-tagged PD.
• Quantified leaf pit field density across leaf development using light microscopy.
• Performed temporal mRNA sequencing and gene co-expression network analysis.

Main Results:

• Setaria (C4) consistently showed higher PD connections at the M-BS interface compared to rice (C3).
• Leaf pit field density was influenced by light as a trigger, and by cell type and function.
• PD density patterns correlated with differentially expressed PD-associated and photosynthesis-related genes.

Conclusions:

• The study provides the first spatiotemporal atlas of PD density in monocot leaves.
• Identified PD-associated genes involved in cell wall expansion, translation, and chloroplast signaling.
• Highlights the role of PD in optimizing photosynthetic efficiency in C4 plants.