A combinatorial TRM-OFP module bilaterally fine-tunes tomato fruit shape

Area of Science:

• Plant Biology
• Developmental Biology
• Genetics

Background:

• Plant organ shape, particularly fruit morphology, is complex and not fully understood.
• TONNEAU1 Recruiting Motif (TRM) proteins are known to influence organ shape in plants like tomato.
• The specific in planta functions of TRM proteins and their interactions with Ovate Family Proteins (OFPs) in regulating shape remain largely unknown.

Purpose of the Study:

• To investigate the roles of TRM proteins and their M8 interaction domain in regulating plant organ shape.
• To elucidate the in planta function of the TRM-OFP interaction in controlling fruit morphology.

Main Methods:

• Utilized CRISPR/Cas9 gene editing to create knockout mutants for various TRM proteins.
• Generated in-frame mutants within the TRM M8 domain to study protein interactions.
• Analyzed the effects of these mutations on tomato fruit shape along mediolateral and proximo-distal axes.

Main Results:

• TRM proteins significantly impact plant organ shape along multiple growth axes.
• Mutations in Sltrm3/4 and Sltrm5 additively resulted in rounder fruit, rescuing the elongated phenotype of ovate/Slofp20 mutants.
• Conversely, mutations in Sltrm19 and Sltrm17/20a led to fruit elongation and exacerbated the obovoid phenotype in ovate/Slofp20 mutants.

Conclusions:

• TRM proteins play crucial, often combinatorial, roles in regulating plant organ shape.
• The TRM-OFP regulon exhibits both redundant and opposing functions throughout plant development to control morphology.
• Findings highlight the complex genetic interactions underlying plant organ shape determination.