Lectin Receptor-like Kinase Signaling during Engineered Ectomycorrhiza Colonization

Area of Science:

• Plant-microbe interactions
• Molecular plant pathology
• Symbiosis signaling

Background:

• Mutualistic plant-fungal associations enhance plant health and productivity.
• G-type lectin receptor-like kinase (PtLecRLK1) from *Populus trichocarpa* facilitates beneficial fungal (*Laccaria bicolor*) root colonization.
• Engineering PtLecRLK1 can enable fungal colonization in non-host plants.

Purpose of the Study:

• To investigate the intracellular signaling pathways regulated by PtLecRLK1 during *Laccaria bicolor* recognition.
• To identify phosphorylation-dependent signaling events mediating symbiosis establishment and maintenance.

Main Methods:

• Phosphoproteomics analysis in transgenic switchgrass roots expressing *PtLecRLK1*.
• Investigated signaling pathways including plant defense, MAPK, phytohormone, ROS balance, endocytosis, cytoskeleton dynamics, and proteasomal degradation.
• Protein-protein interaction analysis to identify downstream effectors.

Main Results:

• *PtLecRLK1* recognition of *L. bicolor* modulates chitin-triggered plant defense and MAPK signaling.
• Significant adjustments in phytohormone signaling, reactive oxygen species (ROS) balance, endocytosis, cytoskeleton movement, and proteasomal degradation were observed.
• Protein-protein interaction data suggest a cGMP-dependent protein kinase as a potential substrate.

Conclusions:

• *PtLecRLK1* plays a crucial role in reprogramming plant signaling to facilitate beneficial fungal symbiosis.
• The findings reveal a complex network of cellular processes regulated by PtLecRLK1 for successful fungal colonization.
• Understanding these mechanisms offers potential for engineering enhanced plant-microbe interactions.