Microbial pattern recognition suppresses de novo organogenesis.

Area of Science:

• Plant developmental biology
• Plant-microbe interactions
• Molecular plant pathology

Background:

• De novo root regeneration (DNRR) is vital for plant propagation and stress response.
• Microbial interactions can influence plant development, but their impact on DNRR is poorly understood, especially outside sterile conditions.
• Pathogen-associated molecular pattern (PAMP)-triggered immunity plays a role in plant defense against microbes.

Purpose of the Study:

• To investigate the impact of microbes on de novo root regeneration (DNRR).
• To elucidate the molecular mechanisms underlying microbial inhibition of root regeneration.
• To develop a system for studying DNRR in the presence of microbes.

Main Methods:

• Development of a versatile experimental system to study microbial effects on DNRR.
• Application of bacterial flagellin 22 peptide (flg22) to assess PAMP-triggered immunity.
• Analysis of auxin distribution at wound sites during regeneration.

Main Results:

• Bacteria were found to inhibit DNRR, primarily through the activation of PAMP-triggered immunity.
• Sensing of flg22 by plants significantly inhibited root regeneration.
• This inhibition was linked to interference with auxin maximum formation at the wound site.
• The inhibitory effect involved the microbial pattern recognition receptor complex but appeared independent of salicylic acid signaling.

Conclusions:

• Microbial presence, specifically through PAMP-triggered immunity, can suppress de novo root regeneration.
• Interference with auxin signaling pathways is a key mechanism by which microbes inhibit root formation.
• The findings highlight a critical crosstalk between plant immunity and developmental processes like regeneration.