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Article|01 Jun 2021|OPEN
Identification and characterization of GLOBE, a major gene controlling fruit shape and impacting fruit size and marketability in tomato
Edgar Sierra-Orozco1, Reza Shekasteband2, Eudald Illa-Berenguer3, Ashley Snouffer3, Esther van der Knaap3,4, Tong Geon Lee1 & Samuel F. Hutton1,
1University of Florida, Gulf Coast Research and Education Center, 14625 County Road 672, Wimauma, FL 33598, USA
2North Carolina State University, Department of Horticultural Science, Mountain Horticultural Crops Research and Extension Center, 455 Research Drive, Mills River, NC 28759, USA
3University of Georgia, Center for Applied Genetic Technologies, 111 Riverbend Road, Athens, GA 30602, USA
4 University of Georgia, Department of Horticulture, 1111 Plant Sciences Bldg, Athens, GA 30602, USA

Horticulture Research 8,
Article number: 138 (2021)
doi: 10.1038/hortres.2021.138
Views: 209

Received: 01 Jun 2020
Revised: 09 Apr 2021
Accepted: 12 Apr 2021
Published online: 01 Jun 2021

Abstract

Within large-fruited germplasm, fruit size is influenced by flat and globe shapes. Whereas flat fruits are smaller and retain better marketability, globe fruits are larger and more prone to cuticle disorders. Commercial hybrids are often developed from crosses between flat and globe shaped parents because flat shape is thought to be dominant and fruit size intermediate. The objectives of this study were to determine the genetic basis of flat/globe fruit shape in large-fruited fresh-market tomato germplasm and to characterize its effects on several fruit traits. Twenty-three advanced single plant selections from the Fla. 8000 × Fla. 8111B cross were selectively genotyped using a genome-wide SNP array, and inclusive composite interval mapping identified a single locus on the upper arm of chromosome 12 associated with shape, which we termed globe. A 238-plant F2 population and 69 recombinant inbred lines for this region from the same parents delimited globe to approximately 392-kilobases. A germplasm survey representing materials from multiple breeding programs demonstrated that the locus explains the flat/globe shape broadly. A single base insertion in an exon of Solyc12g006860, a gene annotated as a brassinosteroid hydroxylase, segregated completely with shape in all populations tested. CRISPR/Cas9 knock out plants confirmed this gene as underlying the globe locus. In silico analysis of the mutant allele of GLOBE among 595 wild and domesticated accessions suggested that the allele arose very late in the domestication process. Fruit measurements in three genetic backgrounds evidenced that globe impacts fruit size and several fruit shape attributes, pedicel length/width, and susceptibility of fruit to weather check. The mutant allele of GLOBE appears mostly recessive for all traits except fruit size where it acts additively.