[Pectin methylesterase as a factor of plant transcriptome stability]

Area of Science:

• Plant molecular biology
• Plant pathology
• Biochemistry

Context:

• Pectin methylesterase (PME) is a cell wall enzyme involved in plant growth and morphogenesis.
• Recent studies suggest PME's role in gene silencing, virus reproduction, and transgenesis.
• The specific role of PME in plant antivirus defense mechanisms remains to be fully elucidated.

Purpose:

• To investigate the role of Pectin methylesterase (PME) in plant antivirus resistance.
• To determine if increased PME enzymatic activity affects tobacco mosaic virus (TMV) reproduction and movement within plants.

Summary:

• Increasing PME enzymatic activity, induced by additional PME gene expression or even an empty vector, suppressed TMV reproduction.
• This suppression included both short- and long-distance virus movement in plants.
• Increased PME activity was observed in stably transformed plants (tobacco, N. benthamiana) expressing TMV movement protein or GFP, and in tomato plants co-suppressing polygalacturonase.
• Light-induced psbO gene activation correlated with PME gene transcription, suggesting PME activity helps restore transcriptome balance after foreign gene introduction or excess transcription.

Impact:

• Demonstrates a novel role for PME in plant antivirus defense.
• Suggests PME as a potential target for engineering enhanced plant resistance to viral diseases.
• Highlights the link between PME activity, gene expression, and maintaining plant cellular homeostasis.