The shikimate pathway regulates programmed cell death

Area of Science:

• Plant Biology
• Metabolic Pathways
• Cell Death Mechanisms

Background:

• Programmed cell death (PCD) is crucial for plant development and immunity.
• The regulation of PCD in plants remains incompletely understood.
• The shikimate pathway's role in PCD has not been previously established.

Purpose of the Study:

• To investigate the connection between the shikimate pathway and programmed cell death in Arabidopsis.
• To identify genetic factors regulating this pathway's influence on PCD.

Main Methods:

• Identification and characterization of a photoperiod-dependent lesion-mimic mutant (lis).
• Map-based cloning and whole-genome resequencing to identify the LIS gene (MEE32).
• Metabolic analysis of shikimate levels and genetic screening for suppressors of the lis phenotype.

Main Results:

• The shikimate pathway was found to promote PCD in Arabidopsis.
• The LIS gene encodes MEE32, a bifunctional enzyme in the shikimate pathway, and its mutation leads to increased shikimate levels.
• Genetic suppressors of lis function upstream of MEE32, confirming the pathway's role.
• Exogenous application of shikimate induced PCD.

Conclusions:

• The shikimate pathway plays a significant role in promoting PCD in plants.
• Elevated shikimate levels are implicated as a trigger for PCD.
• This finding provides a potential mechanism for the herbicidal action of glyphosate, which inhibits the shikimate pathway.