fs8.1, a major QTL, sets the pattern of tomato carpel shape well before anthesis

Distribution ofSUN, OVATE, LC, andFASin the Tomato Germplasm and the Relationship to Fruit Shape Diversity

“…When adding the FAS mutation to the SUN-LC mutant background, the fruit is less elongated and, instead, oxheart in shape. Fruit shape in rectangular, ellipsoid, and heart-shaped varieties that do not carry the OVATE or SUN mutation might be controlled by genes such as those underlying the shape QTL fs8.1 and/or tri2.1/dblk2.1 controlling fruit elongation (Grandillo et al, 1996;Ku et al, 2000;Brewer et al, 2007;Gonzalo and van der Knaap, 2008). However, without the knowledge of the underlying genes at fs8.1 and tri2.1/dblk2.1 and the mutations that gave rise to the altered fruit shape phenotype, it is not possible to survey the alleles at these QTL throughout the germplasm.…”

The Genetic, Developmental, and Molecular Bases of Fruit Size and Shape Variation in Tomato

“…Developmental studies with nearly isogenic lines have shown that the change in fruit shape attributed to fs8.1 begins very early in floral/carpel development (Ku et al, 2000), a characteristic shared with ovate, fasciated, and locule number. By anthesis, the carpels have already assumed the blocky, elongated shape that will characterize to the mature fruit.…”

Genetic analysis of reproductive development in tomato

“…The SUN locus encodes an IQD12 protein belonging to the IQ67 domaincontaining family and its transcription levels are responsible for the variation of tomato fruit shape (Xiao et al, 2008). Together with these two loci, quantitative mapping studies (Grandillo et al, 1999;Ku et al, 2000;Brewer et al, 2007;Gonzalo and Van der Knaap, 2008) have shown that several QTLs, emphasizing the well studied fruit shape 8.1 QTL (fs8.1), are also associated to fruit shape variation. Like fasciated and ovate, fs8.1 functions mostly during early floral development and has little if any activity after anthesis (Ku et al, 2000).…”

“…Together with these two loci, quantitative mapping studies (Grandillo et al, 1999;Ku et al, 2000;Brewer et al, 2007;Gonzalo and Van der Knaap, 2008) have shown that several QTLs, emphasizing the well studied fruit shape 8.1 QTL (fs8.1), are also associated to fruit shape variation. Like fasciated and ovate, fs8.1 functions mostly during early floral development and has little if any activity after anthesis (Ku et al, 2000). Presumably, gene interactions controlling shape and size of tomato fruit will soon be elucidated and with this, the molecular mechanisms underlaying morphological variation of tomato fruit.…”