Advances in Agriculture

Review Article

Improvement of Soybean Crop for Yield, Stress Tolerance, and Value-Added Products Using a Transgenic Approach

Table 1

Summary of improved soybean cultivars, target genes, delivery methods, and outcomes of soybean transgenics.


Traits	Cultivar	Gene	Gene source	Delivery method	Outcome	Reference
Dietary supplements

Oil and fatty acid content	Glycine max	DGAT2	Umbelopsis (formerly Mortierella) ramanniana	Agrobacterium-mediated	Increased oil that shows no major impact on protein content or yield; increase in oil of 1.5% (by weight) in the mature seed	Lardizabel et al. [24]
	Glycine max cv. Jack	GmFAD3	Glycine max GmFAD3 RNAi silencing	Agrobacterium-mediated	LA contents below 2%	Flores et al. [26]
	Glycine max	FAD2-1A and -1B	Glycine max FAD2-1A and -1B ribozyme-terminated antisense	Agrobacterium-mediated	Ribozyme downregulates endogenous gene expression; oleic acid levels, greater than 85%, and saturated fatty acids levels, less than 6%	Buhr et al. [27]
	Glycine max cv. Thorne	Δ⁶desaturase	Borago officinalis	Agrobacterium-mediated	Converts LA and α-linolenic; GLA to ∼27% and SDA to ∼3% in seed oil (ALA) to GLA and SDA	Sato et al. [31]; Clement et al. [32]
	Glycine max cv. Williams 82	Delta-12 oleate desaturase GmFad2-1b gene	Glycine max cv Williams 82,	Agrobacterium-mediated	Increase in oleic acid (up to 51.71%) and a reduction in palmitic acid (to <3%) in their seed oil content	Zhang et al. [33]

Protein and amino acid content	Glycine max cv. Jack	β-Casein	Bovine milk protein, β-casein	Particle bombardment	Produces bovine β-casein; seed accumulated 0.1–0.4%	Maughan et al. [34]
	Glycine max cv. Maverick	O-acetylserine sulfhydrylase (OASS)	Overexpressed	Agrobacterium-mediated	Increase in the level of protein-bound cysteine (58–74%) and free cysteine (22–32%)	Kim et al. [35]
	Glycine max cv. Jack	Zein	Zea mays	Agrobacterium-mediated	20% increase in methionine and a 15–35% increase in cysteine	Dinkins et al. [36]
	Glycine max	AK and DHDPS	E. coli and Corynebacterium	Agrobacterium-mediated	Increase of free lysine >100-fold and total seed lysine 5-fold	Falco et al. [30]
	Glycine max cv. A3525	Aspartate kinase (AK)	Xenorhabdus bovienii	Agrobacterium-mediated	Increase in threonine and free amino acid levels by 100-fold and 3.5-fold, respectively	Qi et al. [37]
	Glycine max cv. Zigongdongdou (ZD)	Cystathionine γ-synthase (AtD-CGS)	Arabidopsis thaliana	Agrobacterium-mediated	Met incorporated into proteins, increase in mature seeds by 1.8- and 2.3-fold, respectively	Song et al. [38]

Tocopherols	Glycine max cv. A3244	Homogentisate phytyltransferase (HPT)	Synechocystis sp.	Agrobacterium-mediated	Increase of tocopherol by 15-fold	Karunanandaa et al. [39]
	Glycine max cv. Iksannamulkong	Homogentisate geranylgeranyl transferase (HGGT)	Oryza sativa	Agrobacterium-mediated	Enhanced vitamin E and all forms of tocopherol levels	Kim et al. [40]
	Glycine max	VTE3 and VTE4	Arabidopsis thaliana	Agrobacterium-mediated	Seeds accumulated >95% α-tocopherol	Van Eenennaam et al. [41]
	Glycine max cv. Jack	γ-Tocopherol methyltransferase (γ-TMT)	Perilla frutescens	Particle bombardment	10.4-fold increase in α-tocopherol content and a 14.9-fold increase in β-tocopherol content in seeds	Tavva et al. [42]

β-Carotene	Glycine max cv. Kwangan	Phytoene synthase-2A-carotene desaturase	Capsicum phytoene synthase (Psy) and Pantoea carotene desaturase (CrtI)	Agrobacterium-mediated	Transgenic seeds accumulated 146 mg/g of total carotenoids, of which 112 mg/g (77%) was β-carotene	Kim et al. [43]
	Glycine max L. cv. Jack	Phytoene synthase gene (crtB)	Pantoea ananatis	Particle bombardment	Plastids accumulated 845 µg β-carotene g⁻¹ dry seed weight	Schmidt et al. [44]
	Glycine max cv. Jack	Phytoene synthase gene (crtB), ketolase genes (crtW from Brevundimonas sp. strain SD212 and bkt1 from Haematococcus pluvialis)	Pantoea ananatis, Brevundimonas sp. strain SD212, Haematococcus pluvialis	Particle bombardment	Transgenic seeds accumulated higher astaxanthin, lutein, β carotene, phytoene, α-carotene, lycopene, and β-cryptoxanthin	Pierce et al. [45]

Pharmaceuticals

Vaccines	Glycine max cv Williams 82, W82 cell suspension cultures	Hepatitis B surface antigen (HBsAg)	Hepatitis B virus	Agrobacterium-mediated	Plant-expressed HBsAg was retained intracellularly; HBsAg titers were obtained with soybean suspension cultures 20–22 mg/L	Smith et al. [46]
	Glycine max cv. Thorne	FanC	E. coli	Agrobacterium-mediated	Accumulation of FanC antigen; ∼0.4% TSP in both leaves and seeds	Piller et al. [47]
	Glycine max cv. Jack	Enterotoxigenic heat-labile toxin B subunit (LTB)	E. coli	Particle bombardment	Immunogenic and partial protection against LT challenge in mice; transgenic produces 2.4% total seed protein at maturity	Moravec et al. [48]
	Glycine max cv. Jack and Kunitz	Nucleocapsid protein (PRRSV-ORF7)	PRRS virus	Agrobacterium-mediated	Accumulated nucleocapsid protein (PRRSV-ORF7); transgenic plants accumulated to 0. 64% of TSP	Vimolmangkang et al. [49]
	Glycine max	Enterotoxin B (mSEB)	S. aureus	Agrobacterium-mediated	Seed extracts containing mSEB showed an immune response; ∼76 theoretical doses of human vaccine per single soybean seed	Laura et al. [50]
Antibodies	Glycine max	Monoclonal antibody	Humanized monoclonal anti-herpes simplex virus 2 (HSV-2) antibody	Particle acceleration method	Antibody in leaf tissue	Zeitlin et al. [51]

Therapeutics	Glycine max	Growth hormone (hGH)	Human	Agrobacterium-mediated	Expressed the mature form of hGH; 0.0008% TSP	Russell et al. [52]
	Glycine max cv. Sichuan	Human basic fibroblast growth factor (bFGF)	Human fetal brain cDNAs	Agrobacterium-mediated	Accumulated human basic fibroblast growth factor (bFGF); 2.3% total seed protein at maturity	Ding et al. [53]
	Glycine max cv. Jack	Novokinin peptide gene	Ovalbumin	Whisker-mediated transformation	Transgenic soybean accumulates Novokinin (0.5% of TSP)	Yamada et al. [54]
	Glycine max cv. Jack	Suppression of the α/α′ subunit of β-conglycinin storage protein synthesis	Glycine max	Particle bombardment	Suppression of the α/α′ subunit of β-conglycinin (>7% (w/w) of the total protein in seeds)	Schmidt and Herman [55]
	Glycine max cv. Williams 82	Human thyroglobulin gene (hTG)	Human	Agrobacterium-mediated	Produces thyroglobulin ∼1.5% of total soluble seed protein	Powell et al. [56]
	Glycine max	Human growth hormone (hGH)	Human	Particle bombardment	Expressed the mature form of hGH in their seeds; bioactive hGH up to 2.9% of the total soluble seed protein content	Cunha et al. [57]
	Glycine max cv. Conquista	Human proinsulin gene	Human	Particle bombardment	Plants expressed the proinsulin gene and accumulated in mature seed	Cunha et al. [58]
	Glycine max cv. BR16	Human coagulation factor IX (hFIX)	Human	Particle bombardment	Accumulated hFIX protein to seed; 0.23% of TSP	Cunha et al. [59]
	Glycine max cv. Jack	Epidermal growth factor (EGF)	Human	Particle bombardment	EGF protein produced in soybean seed; accumulated a range of 6.7 ± 3.1 to 129.0 ± 36.7 μg EGF/g of dry soybean seed	He et al. [60]
Bioactive metabolites	Glycine max cv. Jack	C1 and R transcription factors	Zea mays	Particle bombardment	Increased levels of isoflavones	Yu et al. [61]

Abiotic stress tolerance

Salt tolerance	Glycine max cv. DongNong-50	WRKY transcription factors	Medicago sativa	Agrobacterium-mediated	Overexpression improves salt tolerance in soybean	Wang et al. [62]
	Glycine max cv. DT26	H⁺-pyrophosphatase gene (AtAVP1) and Na⁺/H⁺ antiporter gene (AtNHX1)	Arabidopsis thaliana	Agrobacterium-mediated	Enhances salt tolerance	Nguyen et al. [63]
	Glycine max cv. Bert	AtMYB44	Arabidopsis thaliana	Agrobacterium-mediated	Enhanced drought/salt stress tolerance	Seo et al. [64]
	Glycine max cv. Kwangankong	AtABF3	Arabidopsis thaliana	Agrobacterium-mediated	Overexpression conferred drought and salt tolerance	Kim et al. [65]
	Glycine max	GmFDL19	Glycine max	Agrobacterium-mediated	Enhanced drought and salt tolerance	Li et al. [66]

Drought tolerance	Glycine max cv. Conquista	soyBiPD gene	Glycine max	Particle bombardment	Increased drought resistance	Valente et al. [67]
	Glycine max	P5CR	Arabidopsis thaliana	Agrobacterium-mediated	Increased drought resistance	De Ronde et al. [68,69]
	Glycine max cv. BR16	AtDREB1A	Arabidopsis thaliana	Particle-bombardment	Increased drought resistance	de Paiva Rolla et al. [70]
	Glycine max cv. BR16	AtDREB1A, AtDREB2CA, AtAREB1 transcription factors	Arabidopsis thaliana	Particle-bombardment	Increased drought resistance	Fuganti-Pagliarini et al. [71]
	Glycine max cv. Zhonghuang 20	LOS5/ABA3	Arabidopsis thaliana	Agrobacterium-mediated	Increased drought resistance; seed yield of transgenic plants is at least 21% at field	Li et al. [72]

Biotic stress tolerance

Viral	Glycine max cv. Fayette	Coat protein precursor (CP-P) gene	Bean pod mottle virus (BPMV)	Agrobacterium-mediated	Increased resistance	Di et al. [73]
	Glycine max cv. Jack	Capsid polyprotein (pCP) gene	Bean pod mottle virus (BPMV)	Particle bombardment	Increased resistance	Reddy et al. [74]
	Glycine max cv. 9341	Coat protein gene	Soybean mosaic virus (SMV)	Agrobacterium-mediated	Highly resistant to SMV	Wang et al. [75]
	Glycine max cv. Jack	Coat protein gene	Soybean dwarf virus (SbDV)	Particle bombardment	Increased resistance to SbDV	Tougou et al. [76,77]
	Glycine max cv. Williams 82	GmAKT2	Glycine max	Agrobacterium-mediated	Enhances SMV resistance	Zhou et al. [78]
	Glycine max cv. Tianlong, Huachun, Huachun, Williams 82, Jack and Kwangan	HC-Pro gene	Soybean mosaic virus	Agrobacterium-mediated	Enhances SMV resistance	Gao et al. [79]; Kim et al. [80]

Fungal	Glycine max cv. BR-16	Oxalate decarboxylase (OXDC)	Flammulina sp.	Particle bombardment	Enhances white mould resistance	Cunha et al. [81]
	Glycine max cv. Heinong-35, Hefeng-35, Dongnong-42 and Jilin-30	Chitinase (CHI) and the barley ribosome-inactivating protein (RIP)	Bean and barley	Agrobacterium-mediated	Enhances fungal disease resistance	Li et al. [82]
	Glycine max cv. Williams 82	Antibody gene encoding scFv	Hybridoma cell line	Agrobacterium-mediated	Enhances foliar sudden death syndrome resistance	Brar and Bhattacharyya [83]
	Glycine max cv. Williams 82	Non-host resistance (NHR) gene	Arabidopsis thaliana	Agrobacterium-mediated	Enhances resistance to rust disease	Langenbach et al. [84]
	Glycine max	CcRpp1	Cajanus cajan	Particle bombardment	Showed full resistance to Asian soybean rust	Kawashima et al. [85]
	Glycine max cv. Shennong 9	hrf2	Xanthomonas oryzae pv. oryzicola	Agrobacterium-mediated	Enhances resistance to P. sojae	Niu et al. [86]

Nematode	Glycine max cv. Jack and Chapman	Major sperm protein (MSP) gene	Heterodera glycines	Particle bombardment	Control of the soybean cyst nematode	Steeves et al. [87]
	Glycine max cv. KS4607	Cpn-1, Y25, and Prp-17	Heterodera glycines	Agrobacterium-mediated	Control of the soybean cyst nematode	Li et al. [88]
	Glycine max cv. Williams 82	Tyrosine phosphatase (TP) and mitochondrial stress-70 protein precursor (MSP)	Meloidogyne incognita	Agrobacterium-mediated	Decreased root-knot nematodes; decreased by >90%	Ibrahim et al. [89]
	Glycine max cv. Williams 82	SAMT1	Glycine max	Agrobacterium-mediated	Resistance to soybean cyst nematode	Lin et al. [90]
	Glycine max cv. Williams 82	PAD4	Arabidopsis thaliana	Agrobacterium-mediated	Resistance to soybean cyst nematode and root-knot nematode	Youssef et al. [91]
	Glycine max cv. Williams 82	CLE-receptor	Glycine max	Agrobacterium-mediated	Enhances resistance to soybean cyst nematode	Guo et al. [92]
	Glycine max cv. JackX	HgY25, HgPrp17	Heterodera glycines	Particle Inflow gun	Enhances resistance to soybean cyst nematode	Tian et al. [93]

Insect	Glycine max cv. Williams 82, MB80-281	Cry1A(b)	Bacillus thuringiensis (Bt)	Microprojectile bombardment	Increased insect resistance	Parrott et al. [94]
	Glycine max cv. Jack	Cry1Ac	Bacillus thuringiensis (Bt)	Particle bombardment	Increased insect resistance to lepidopteran populations	Stewart et al. [95]
	Glycine max cv. Jack	Cry1Ac	Bacillus thuringiensis (Bt)	Particle bombardment	Increased insect resistance to lepidopteron populations	Walker et al. [96]
	Glycine max	Cry1A	Bacillus thuringiensis (Bt)	Agrobacterium-mediated	Increased insect resistance to lepidopteron populations	Miklos et al. [97]
	Glycine max cv. IAS5	Cry1Ac	Bacillus thuringiensis (Bt)	Particle bombardment	Increased insect resistance to A. gemmatalis	Homrich et al. [98]
	Glycine max	Cry1A	Bacillus thuringiensis (Bt)	Agrobacterium-mediated	Increased insect resistance to lepidopteron populations	Mcpherson and MacRae [99]
	Soybean Roundup Ready®	EPSPS	Agrobacterium spp. strain CP4	Particle acceleration method	Tolerant to herbicide glyphosate	Padgette et al. [100]
	Glycine max cv. CV127	csr1-2	Arabidopsis thaliana	Particle bombardment	Tolerant to herbicides of the imidazolinone chemical class	Homrich et al. [101]
	Glycine max cv. Thorne	Dicamba monooxygenase	Pseudomonas maltophilia (strain DI-6)	Agrobacterium-mediated	Resistance to treatment with dicamba	Behrens et al. [102]