Abstract
Soybean seeds produce oil enriched in oxidatively unstable polyunsaturated fatty acids (PUFAs) and are also a potential biotechnological platform for synthesis of oils with nutritional omega-3 PUFAs. In this study, we engineered soybeans for seed-specific expression of a barley homogentisate geranylgeranyl transferase (HGGT) transgene alone and with a soybean γ-tocopherol methyltransferase (γ-TMT) transgene. Seeds for HGGT-expressing lines had 8- to 10-fold increases in total vitamin E tocochromanols, principally as tocotrienols, with little effect on seed oil or protein concentrations. Tocochromanols were primarily in δ- and γ-forms, which were shifted largely to α- and β-tocochromanols with γ-TMT co-expression. We tested whether oxidative stability of conventional or PUFA-enhanced soybean oil could be improved by metabolic engineering for increased vitamin E antioxidants. Selected lines were crossed with a stearidonic acid (SDA, 18:4Δ6,9,12,15)-producing line, resulting in progeny with oil enriched in SDA and α- or γ-linoleic acid (ALA, 18:3Δ9,12,15 or GLA, 18:3Δ6,9,12), from transgene segregation. Oil extracted from HGGT-expressing lines had ≥6-fold increase in free radical scavenging activity compared to controls. However, the oxidative stability index of oil from vitamin E-enhanced lines was ~15% lower than that of oil from non-engineered seeds and nearly the same or modestly increased in oil from the GLA, ALA and SDA backgrounds relative to controls. These findings show that soybean is an effective platform for producing high levels of free-radical scavenging vitamin E antioxidants, but this trait may have negative effects on oxidative stability of conventional oil or only modest improvement of the oxidative stability of PUFA-enhanced oil.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 63-73 |
| Number of pages | 11 |
| Journal | Metabolic Engineering |
| Volume | 57 |
| DOIs | |
| State | Published - Jan 2020 |
Fingerprint
Keywords
- Antioxidant
- Homogentisate geranylgeranyl transferase
- Oilseed
- Soybean
- Tocochromanol
- Tocopherol
- Tocotrienol
- Vitamin E
ASJC Scopus subject areas
- Biotechnology
- Bioengineering
- Applied Microbiology and Biotechnology
Cite this
Metabolic engineering of soybean seeds for enhanced vitamin E tocochromanol content and effects on oil antioxidant properties in polyunsaturated fatty acid-rich germplasm. / Konda, Anji Reddy; Nazarenus, Tara J.; Nguyen, Hanh; Yang, Junsi; Gelli, Malleswari; Swenson, Samantha; Shipp, Jamie M.; Schmidt, Monica A.; Cahoon, Rebecca E.; Ciftci, Ozan N.; Zhang, Chunyu; Clemente, Tom Elmo; Cahoon, Edgar B.
In: Metabolic Engineering, Vol. 57, 01.2020, p. 63-73.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Metabolic engineering of soybean seeds for enhanced vitamin E tocochromanol content and effects on oil antioxidant properties in polyunsaturated fatty acid-rich germplasm
AU - Konda, Anji Reddy
AU - Nazarenus, Tara J.
AU - Nguyen, Hanh
AU - Yang, Junsi
AU - Gelli, Malleswari
AU - Swenson, Samantha
AU - Shipp, Jamie M.
AU - Schmidt, Monica A.
AU - Cahoon, Rebecca E.
AU - Ciftci, Ozan N.
AU - Zhang, Chunyu
AU - Clemente, Tom Elmo
AU - Cahoon, Edgar B.
PY - 2020/1
Y1 - 2020/1
N2 - Soybean seeds produce oil enriched in oxidatively unstable polyunsaturated fatty acids (PUFAs) and are also a potential biotechnological platform for synthesis of oils with nutritional omega-3 PUFAs. In this study, we engineered soybeans for seed-specific expression of a barley homogentisate geranylgeranyl transferase (HGGT) transgene alone and with a soybean γ-tocopherol methyltransferase (γ-TMT) transgene. Seeds for HGGT-expressing lines had 8- to 10-fold increases in total vitamin E tocochromanols, principally as tocotrienols, with little effect on seed oil or protein concentrations. Tocochromanols were primarily in δ- and γ-forms, which were shifted largely to α- and β-tocochromanols with γ-TMT co-expression. We tested whether oxidative stability of conventional or PUFA-enhanced soybean oil could be improved by metabolic engineering for increased vitamin E antioxidants. Selected lines were crossed with a stearidonic acid (SDA, 18:4Δ6,9,12,15)-producing line, resulting in progeny with oil enriched in SDA and α- or γ-linoleic acid (ALA, 18:3Δ9,12,15 or GLA, 18:3Δ6,9,12), from transgene segregation. Oil extracted from HGGT-expressing lines had ≥6-fold increase in free radical scavenging activity compared to controls. However, the oxidative stability index of oil from vitamin E-enhanced lines was ~15% lower than that of oil from non-engineered seeds and nearly the same or modestly increased in oil from the GLA, ALA and SDA backgrounds relative to controls. These findings show that soybean is an effective platform for producing high levels of free-radical scavenging vitamin E antioxidants, but this trait may have negative effects on oxidative stability of conventional oil or only modest improvement of the oxidative stability of PUFA-enhanced oil.
AB - Soybean seeds produce oil enriched in oxidatively unstable polyunsaturated fatty acids (PUFAs) and are also a potential biotechnological platform for synthesis of oils with nutritional omega-3 PUFAs. In this study, we engineered soybeans for seed-specific expression of a barley homogentisate geranylgeranyl transferase (HGGT) transgene alone and with a soybean γ-tocopherol methyltransferase (γ-TMT) transgene. Seeds for HGGT-expressing lines had 8- to 10-fold increases in total vitamin E tocochromanols, principally as tocotrienols, with little effect on seed oil or protein concentrations. Tocochromanols were primarily in δ- and γ-forms, which were shifted largely to α- and β-tocochromanols with γ-TMT co-expression. We tested whether oxidative stability of conventional or PUFA-enhanced soybean oil could be improved by metabolic engineering for increased vitamin E antioxidants. Selected lines were crossed with a stearidonic acid (SDA, 18:4Δ6,9,12,15)-producing line, resulting in progeny with oil enriched in SDA and α- or γ-linoleic acid (ALA, 18:3Δ9,12,15 or GLA, 18:3Δ6,9,12), from transgene segregation. Oil extracted from HGGT-expressing lines had ≥6-fold increase in free radical scavenging activity compared to controls. However, the oxidative stability index of oil from vitamin E-enhanced lines was ~15% lower than that of oil from non-engineered seeds and nearly the same or modestly increased in oil from the GLA, ALA and SDA backgrounds relative to controls. These findings show that soybean is an effective platform for producing high levels of free-radical scavenging vitamin E antioxidants, but this trait may have negative effects on oxidative stability of conventional oil or only modest improvement of the oxidative stability of PUFA-enhanced oil.
KW - Antioxidant
KW - Homogentisate geranylgeranyl transferase
KW - Oilseed
KW - Soybean
KW - Tocochromanol
KW - Tocopherol
KW - Tocotrienol
KW - Vitamin E
UR - http://www.scopus.com/inward/record.url?scp=85074233025&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85074233025&partnerID=8YFLogxK
U2 - 10.1016/j.ymben.2019.10.005
DO - 10.1016/j.ymben.2019.10.005
M3 - Article
C2 - 31654815
AN - SCOPUS:85074233025
VL - 57
SP - 63
EP - 73
JO - Metabolic Engineering
JF - Metabolic Engineering
SN - 1096-7176
ER -