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The flowering gene SINGLE FLOWER TRUSS drives heterosis for yield in tomato


Intercrossing different varieties of plants frequently produces hybrid offspring with superior vigor and increased yields, in a poorly understood phenomenon known as heterosis1,2. One classical unproven model for heterosis is overdominance, which posits in its simplest form that improved vigor can result from a single heterozygous gene3,4,5,6,7,8. Here we report that heterozygosity for tomato loss-of-function alleles of SINGLE FLOWER TRUSS (SFT), which is the genetic originator of the flowering hormone florigen, increases yield by up to 60%. Yield overdominance from SFT heterozygosity is robust, occurring in distinct genetic backgrounds and environments. We show that several traits integrate pleiotropically to drive heterosis in a multiplicative manner9, and these effects derive from a suppression of growth termination mediated by SELF PRUNING (SP), an antagonist of SFT. Our findings provide the first example of a single overdominant gene for yield and suggest that single heterozygous mutations may improve productivity in other agricultural organisms.

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Figure 1: Heterozygosity for loss-of-function mutations in SFT drives heterosis in tomato.
Figure 2: sft/+ heterozygosity causes heterosis in distinct genetic backgrounds and growth conditions.
Figure 3: SFT-dependent heterosis arises from multiple phenotypic changes on component traits that integrate to improve yield.
Figure 4: Overdominance for inflorescence production is based on a dosage-dependent suppression of growth termination mediated by SP.

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We thank D. Jackson, R. Martienssen, Y. Semel, Y. Eshed and members of the Lippman laboratory for comments and discussion. We also thank the researchers and field crew at the Western Galilee experimental station in Akko, Israel, Kibbutz Kfar Masaryk, Israel and Cornell University's Long Island Horticultural Research and Extension Center in Riverhead, New York. This research was supported by individual grants from the European Commission EU-SOL Project and The Israel Science Foundation (ISF) to D.Z. and from a Heterosis Challenge Grant DBI-0922442 from the United States National Science Foundation Plant Genome Research Program to Z.B.L.

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U.K., Z.B.L. and D.Z. planned and carried out all experiments, collected the data, performed the statistical analyses and wrote the paper.

Corresponding authors

Correspondence to Zachary B Lippman or Dani Zamir.

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Competing interests

D.Z. is a cofounder of Phenom Networks, a privately held company that is serving as a repository and online statistical analysis platform for the raw heterosis field data.

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Krieger, U., Lippman, Z. & Zamir, D. The flowering gene SINGLE FLOWER TRUSS drives heterosis for yield in tomato. Nat Genet 42, 459–463 (2010).

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