Metabolic engineering of soybean affords improved phytosterol seed traits

Anjanasree K. Neelakandan, Swetha Chamala, Babu Valliyodan, William David Nes, Henry T. Nguyen

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

Different combinations of three rate-limiting enzymes in phytosterol biosynthesis, the Arabidopsis thaliana hydroxyl methylglutaryl CoA1 (HMGR1) catalytic subunit linked to either constitutive or seed-specific β-conglycinin promoter, and the Glycine max sterol methyltransferase1 (SMT1) and sterol methyltransferase2-2 (SMT2-2) genes, under the control of seed-specific Glycinin-1 and Beta-phaseolin promoters, respectively, were engineered in soybean plants. Mature seeds of transgenic plants displayed modest increases in total sterol content, which points towards a tight control of phytosterol biosynthesis. However, in contrast to wild-type seeds that accumulated about 35% of the total sterol in the form of intermediates, in the engineered seeds driven by a seed-specific promoter, metabolic flux was directed to Δ 5-24-alkyl sterol formation (99% of total sterol). The engineered effect of end-product sterol (sitosterol, campesterol, and stigmasterol) over-production in soybean seeds resulted in an approximately 30% increase in overall sitosterol synthesis, a desirable trait for oilseeds and human health. In contradistinction, increased accumulation of cycloartenol and 24(28)-methylencylartanol (55% of the total sterol) was detected in plants harbouring the constitutive t-HMGR1 gene, consistent with the previous studies. Our results support the possibility thatmetabolic flux of the phytosterol family pathway is differentially regulated in leaves and seeds.

Original languageEnglish (US)
Pages (from-to)12-19
Number of pages8
JournalPlant Biotechnology Journal
Volume10
Issue number1
DOIs
StatePublished - Jan 1 2012

Keywords

  • Phytosterol biosynthesis
  • Seed-specific Promoter
  • Soybean
  • Sterol 24-C-methyltransferase
  • Transgenic seed

ASJC Scopus subject areas

  • Biotechnology
  • Agronomy and Crop Science
  • Plant Science

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    Neelakandan, A. K., Chamala, S., Valliyodan, B., Nes, W. D., & Nguyen, H. T. (2012). Metabolic engineering of soybean affords improved phytosterol seed traits. Plant Biotechnology Journal, 10(1), 12-19. https://doi.org/10.1111/j.1467-7652.2011.00623.x