Genetic control of tomato fruit cracking through SlPMEI27-dependent pectin modification

Area of Science:

• Plant Biology
• Molecular Genetics
• Biochemistry

Background:

• Fruit cracking in tomatoes significantly reduces crop quality and yield.
• Pectin methylesterases (PMEs) play a critical role in cell wall modification and fruit development.

Purpose of the Study:

• To investigate the role of the SlPMEI27 gene in regulating tomato fruit cracking.
• To elucidate the molecular mechanisms by which SlPMEI27 affects pectin modification and cell wall properties.

Main Methods:

• Genetic transformation (gene knockout and overexpression)
• Immunofluorescence analysis to assess pectin methylation rates
• Transmission electron microscopy to examine cell adhesion and intercellular spaces
• Enzyme activity assays and gene expression analysis (transcriptomics)

Main Results:

• SlPMEI27 knockout enhanced PME activity, decreasing pectin methylation and increasing fruit hardness.
• SlPMEI27 overexpression inhibited PME activity, leading to highly methyl-esterified pectin, reduced cell adhesion, and increased intercellular spaces, thus increasing cracking susceptibility.
• SlPMEI27 interacts with SlGAUT7, regulating pectin biosynthesis and modification.
• Transcriptomic analysis revealed SlPMEI27 influences the expression of cell wall hydrolases (PL, PG, β-Gal) and transcription factors.

Conclusions:

• SlPMEI27 is a key regulator of tomato fruit cracking by modulating pectin methylesterification and cell wall mechanics.
• Pectin methylesterification status is crucial for maintaining cell wall integrity during fruit development.
• Findings provide a theoretical basis for breeding tomatoes with enhanced crack resistance.