A PDLP-NHL3 complex integrates plasmodesmal immune signaling cascades

Area of Science:

• Plant molecular biology
• Plant immunity
• Cell-to-cell communication

Background:

• Plant immune system perceives microbial threats via molecular signals.
• Pathogen perception triggers signal transduction pathways.
• Plasmodesmal closure restricts cell-to-cell communication as an immune response.

Purpose of the Study:

• To establish signaling hierarchy at plasmodesmata.
• To characterize convergence points in microbe elicitor-triggered signaling.
• To identify key components in plant immune signal transduction.

Main Methods:

• Profiling plasmodesmal responses to different elicitors.
• Assessing dependence on plasmodesmal signaling machinery.
• Screening for protein interactors using yeast two-hybrid or co-immunoprecipitation.

Main Results:

• Chitin and flg22 trigger plasmodesmal closure via callose synthesis, converging at or upstream of this process.
• Flg22 signals through RESPIRATORY BURST OXIDASE HOMOLOGUE D (RBOHD) for plasmodesmal closure.
• PLASMODESMATA-LOCATED PROTEIN 1 (PDLP1), PDLP5, and CALLOSE SYNTHASE 1 (CALS1) are common to microbe and salicylic acid (SA)-triggered responses.
• A PDLP-NHL3 complex acts as an integrating node, relaying signals to activate CALS1 and plasmodesmata closure.

Conclusions:

• A PDLP-NHL3 complex integrates multiple immune signals.
• This complex transmits signals to activate CALLOSE SYNTHASE 1 (CALS1).
• The PDLP-NHL3 complex is crucial for plasmodesmata closure during plant immune responses.