Scientists Investigate QTLs Involved in Locule Number of Tomatoes

The number of locules (cavities containing seeds that are derived from carpels) in tomatoes usually ranges from two to 10. Locule number is an important phenotype of tomatoes because it affects the shape and size of the fruit. In previous studies, it has been found that locule number is controlled by a number of quantitative trait loci (QTLs).

Stephane Muños of the Institut National de la Reserche Agronomique (INRA) and colleagues report the map-based cloning of one of the QTLs which is designated as locule number (lc). The lc QTL includes a 1,600-bp region that is located 1,080 bp from the 3′ end of WUSCHEL, which encodes a homeodomain protein that regulates stem cell fate in plants.

Based on the molecular evolution of lc, there is a decrease in the diversity in cultivated accessions except for two single-nucleotide polymorphisms. Results implied that these two single-nucleotide polymorphisms are responsible for the increase in locule number. Thus, a model for locule number is proposed, which suggests that the fas mutation appeared after the mutation in the lc locus to confer the extreme high-locule-number phenotype.

Read more information at http://www.plantphysiol.org/content/156/4/2244.abstract.