SlMBP22 overexpression in tomato affects flower morphology and fruit development

Area of Science:

• Plant Biology
• Molecular Genetics
• Agricultural Science

Background:

• MADS-domain transcription factors regulate flower and fruit development in angiosperms.
• B_sister (B_s) genes are crucial for reproductive organ evolution in seed plants.
• The role of B_s genes in fruit crop development, like tomato, is not well understood.

Purpose of the Study:

• To investigate the function of the B_s MADS-box gene SlMBP22 in tomato (Solanum lycopersicum) reproductive development.
• To elucidate the molecular mechanisms underlying SlMBP22's effects on floral morphology, fruit development, and related traits.

Main Methods:

• Overexpression of SlMBP22 in tomato (SlMBP22-OE).
• Analysis of floral morphology and gene expression.
• Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays for protein interactions.
• Pollen viability, cross-fertilization, and fruit size measurements.

Main Results:

• SlMBP22 overexpression caused significant floral alterations and affected floral homeotic gene expression.
• SlMBP22 interacts with floral homeotic proteins MACROCALYX (MC), TM5, and TM29.
• Strong overexpression led to infertility due to defects in female reproductive development.
• Mild overexpression resulted in smaller fruits via reduced cell expansion.
• SlMBP22 affected proanthocyanidin accumulation and seed dormancy.

Conclusions:

• SlMBP22 plays a critical role in tomato flower and fruit development.
• Protein interactions of SlMBP22 with MC, TM5, and TM29 are essential for its function.
• Understanding SlMBP22's role provides insights into B_s MADS-box gene regulation in fruit crops.