Allelic diversity for SUN, OVATE and FAS genes underlies tomato fruit morphology

RODRÍGUEZ, GUSTAVO RUBÉN; ANDERSON, CLAIRE; MOYSEENKO, JENNYFER B; SIM, SUNG-CHUR; FRANCIS, DAVID; VAN DER KNAAP, ESTHER

St. Luis, Missouri, USA

Congreso; 9th International Plant Molecular Biology; 2009

International Society of Plant Molecular Biology

Phenotypic diversity within cultivated tomato is particularly evident for fruit size and shape. To date, three genes implicated in tomato fruit morphology have been identified by positional cloning. SUN(1) and OVATE(2) produce elongated fruits whereas FAS(3) wider fruit with high locule number. We evaluated the allelic distribution for these genes in a widely varied shape set of cultivated germplasm (N=345) to establish relationships to fruit morphology. Firstly, a new classification system was proposed for fruit shape that is large explained by the alleles of SUN, OVATE, and FAS. Thus, all obovoid tomatoes carry OVATE whereas the oxheart tomatoes carry SUN and/or FAS. SUN is also controlling the long tomato shape whereas OVATE regulates ellipsoid phenotypes on 82% of accessions classified like such. FAS is found to control shape in only 29% of flat fruits. The OVATE allele is also found in some accessions classified as rectangular, heart, long and even fruit found in the round category. Furthermore, we analyzed the population genetic structure for this collection to infer evolutionary history of these genes during the domestication and breeding process as well as to determine relationship among the genotypes and phenotypes. We demonstrated that the population structure is both fruit shape categories and germplasm types dependant. The three genes show differential distribution among the subpopulations and these subpopulations present significant differences for attributes related to fruit morphology. In addition, the results suggest that OVATE and FAS arose early in the tomato domestication process whereas SUN is the most recent mutation. References: (1) Xiao et al. (2008) Science 319:1527-1530; (2) Liu et al. (2002) PNAS 99: 13302-13306; (3) Cong et al. (2008) Nature Genetics 40:800-804. Funded by NSF DBI 0227541