Natural variation and selection in GmSWEET39 affect soybean seed oil content

• Published in: The New phytologist Vol. 225; no. 4; pp. 1651 - 1666
• Main Authors: Miao, Long, Yang, Songnan, Zhang, Kai, He, Jianbo, Wu, Chunhua, Ren, Yanhua, Gai, Junyi, Li, Yan
• Format: Journal Article
• Language: English
• Published: England Wiley 01.02.2020; Wiley Subscription Services, Inc; John Wiley and Sons Inc
• Subjects: Alleles; Arabidopsis - genetics; Arabidopsis - metabolism; Cultivars; DNA sequences; Domestication; Efflux; Gene expression; Gene Expression Regulation, Plant; Gene mapping; Genes; genetic improvement; Genetic Variation; Genetics; Genotype; Glycine (amino acid); Glycine max; Glycine max - genetics; GmSWEET39; Hairy root; Inbreeding; Linkage Disequilibrium; Membrane proteins; natural variation; Oil; Oils & fats; Oilseeds; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Roots; Plants, Genetically Modified; Population genetics; Population studies; Quantitative trait loci; Recombinants; seed oil content; Seeds; Seeds - chemistry; Seeds - metabolism; Selection, Genetic; Sequencing; soybean; Soybean Oil - chemistry; Soybean Oil - metabolism; Soybeans; Sucrose; Sugar; soybean; GmSWEET39; seed oil content; genetic improvement; natural variation
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.16250

Soybean (Glycine max) is a major contributor to the world oilseed production. Its seed oil content has been increased through soybean domestication and improvement. However, the genes underlying the selection are largely unknown. The present contribution analyzed the expression patterns of genes in the seed oil quantitative trait loci with strong selective sweep signals, then used association, functional study and population genetics to reveal a sucrose efflux transporter gene, GmSWEET39, controlling soybean seed oil content and under selection. GmSWEET39 is highly expressed in soybean seeds and encodes a plasma membrane-localized protein. Its expression level is positively correlated with soybean seed oil content. The variation in its promoter and coding sequence leads to different natural alleles of this gene. The GmSWEET39 allelic effects on total oil content were confirmed in the seeds of soybean recombinant inbred lines, transgenic Arabidopsis, and transgenic soybean hairy roots. The frequencies of its superior alleles increased from wild soybean to cultivated soybean, and are much higher in released soybean cultivars. The findings herein suggest that the sequence variation in GmSWEET39 affects its relative expression and oil content in soybean seeds, and GmSWEET39 has been selected to increase seed oil content during soybean domestication and improvement.