Clustered Expansins modulate pedicel length by regulating cell elongation in tomato
Jiaying Wang1, Xinyi Huang1, Yuyang Zhang1,2
1National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
The Plant Journal : for Cell and Molecular Biology
|January 12, 2026
Summary
Researchers identified Tomato Pedicel Length 3 (TPL3) and a cluster of Expansin (EXP) genes controlling tomato pedicel elongation. This discovery offers a molecular marker for breeding tomatoes with improved fruit traits.
Area of Science:
- Plant Biology
- Genetics
- Agricultural Science
Background:
- The tomato pedicel connects fruits to plants, influencing fruit development and harvest. Genetic factors controlling pedicel length (PL) are largely unknown.
- Understanding PL genetics is vital for improving tomato fruit growth, harvesting, and postharvest management.
Purpose of the Study:
- To identify the genetic basis of tomato pedicel length (PL).
- To investigate the role of Expansins (EXPs) in regulating pedicel elongation.
- To develop a molecular marker for breeding tomatoes with optimized PL.
Main Methods:
- Integrated genome-wide association studies (GWAS) and bulked segregant analysis (BSA).
- Generated homozygous mutants using CRISPR/Cas9 to study EXP gene functions.
- Performed biochemical, transcriptomic, and population genetics analyses.
- Developed and validated a molecular marker for PL.
Main Results:
- Identified a high-confidence loci TPL3 harboring a cluster of six Expansins (EXPs) regulating pedicel elongation.
- EXP gene mutations demonstrated dose-dependent effects on pedicel elongation in cortex and pith cells.
- EXPs regulate cell wall composition, reducing cellulose and altering lignin biosynthesis and cell wall remodeling genes.
- Strong selection signatures at TPL3 were detected during tomato evolution.
- Developed a molecular marker for PL with 94.2% genotyping efficiency, useful for commercial cultivars.
Conclusions:
- The EXPs gene cluster at TPL3 is a key regulator of tomato pedicel elongation.
- Pedicel elongation is linked to cell wall modification and reproductive organ development, including fruit weight.
- The developed molecular marker facilitates marker-assisted selection for optimizing PL in tomato breeding programs.
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