Metabolic compensation of steroidal glycoalkaloid biosynthesis in transgenic potato tubers: using reverse genetics to confirm the in vivo enzyme function of a steroidal alkaloid galactosyltransferase

McCue, Kent F.; Shepherd, L.V.T.; Allen, Patrick; Maccree, M. Malendia; Rockhold, David R.; Corsini, D. L.; Davies, Howard V.; Belknap, William R.

doi:10.1016/j.plantsci.2004.08.006

Cited by 100 publications

(82 citation statements)

References 25 publications

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“…It also is a sugar-sugar glycosyltransferase of this triterpene/phytosterol subcluster, although its regiospecificity for the sugar moiety is different from that of Sg-1. Moreover, another member of this subcluster, potato SGT3 also is known to catalyze sugar-sugar rhamnosylation of steroidal saponins, although it shows high sequence similarity to SGT1 and SGT2 that catalyze glycosylation of a steroidal sapogenin, solanidine (McCue et al, 2005(McCue et al, , 2006(McCue et al, , 2007. In general, flavonoid UGTs form distinct functional clusters based on their regiospecificity, suggesting that the regio-specificity arose prior to speciation (Noguchi et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

“…Phylogenetic analysis indicated that Sg-1 a and Sg-1 b are classified in a phylogenetic group known as cluster IIIa represented by flavonoid 7-O-glycosyltransferases (Noguchi et al, 2008) (Figure 5C). More importantly, this cluster was found to include a subcluster composed of various triterpene/ phytosterol-related glycosyltransferases from Fabaceae and Solanaceae (e.g., M. truncatula UGT73K1 and UGT73F3; soybean SGT2/UGT73P2 for saponin; tomato [Solanum lycopersicum] GAME1 [UGT73L5], GAME2 [UGT73L4], and GAME3 [UGT73L6]; potato [Solanum tuberosum] SGT1, SGT2, and SGT3; and Solanum aculeatissimum GT4A for steroidal saponin) (Moehs et al, 1997;Achnine et al, 2005;Kohara et al, 2005;McCue et al, 2005McCue et al, , 2006McCue et al, , 2007Naoumkina et al, 2010;Shibuya et al, 2010;Itkin et al, 2011). Sg-1 a (UGT73F4) and Sg-1 b (UGT73F2) genes apparently show structural similarity to M. truncatula saponin glucosyltransferase UGT73F3 (Naoumkina et al, 2010).…”

Section: Phylogenetics Of Sg-1 Proteinsmentioning

confidence: 99%

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The Sg-1 Glycosyltransferase Locus Regulates Structural Diversity of Triterpenoid Saponins of Soybean

et al. 2012

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Triterpene saponins are a diverse group of biologically functional products in plants. Saponins usually are glycosylated, which gives rise to a wide diversity of structures and functions. In the group A saponins of soybean (Glycine max), differences in the terminal sugar species located on the C-22 sugar chain of an aglycone core, soyasapogenol A, were observed to be under genetic control. Further genetic analyses and mapping revealed that the structural diversity of glycosylation was determined by multiple alleles of a single locus, Sg-1, and led to identification of a UDP-sugar-dependent glycosyltransferase gene (Glyma07g38460). Although their sequences are highly similar and both glycosylate the nonacetylated saponin A0-ag, the Sg-1 a allele encodes the xylosyltransferase UGT73F4, whereas Sg-1 b encodes the glucosyltransferase UGT73F2. Homology models and site-directed mutagenesis analyses showed that Ser-138 in Sg-1 a and Gly-138 in Sg-1 b proteins are crucial residues for their respective sugar donor specificities. Transgenic complementation tests followed by recombinant enzyme assays in vitro demonstrated that sg-1 0 is a loss-of-function allele of Sg-1. Considering that the terminal sugar species in the group A saponins are responsible for the strong bitterness and astringent aftertastes of soybean seeds, our findings herein provide useful tools to improve commercial properties of soybean products.

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Section: Discussionmentioning

confidence: 99%

Section: Phylogenetics Of Sg-1 Proteinsmentioning

confidence: 99%

The Sg-1 Glycosyltransferase Locus Regulates Structural Diversity of Triterpenoid Saponins of Soybean

et al. 2012

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“…The Solanum tuberosum sterol alkaloid glycosyltransferase1 (SGT1) gene behaves in vitro as a UDP-Gal:solanidine galactosyltransferase (Moehs et al, 1997). Silencing SGT1 in potato resulted in redirection of the metabolic flux, causing strong reduction in accumulation of a-solanine and significant accumulation of a-chaconine, in which the primary glycosyl unit is Gal and Glc, respectively (McCue et al, 2005). SGT2 was shown to encode a UDP-Glc:solanidine glucosyltransferase (McCue et al, 2006), which could mediate a-chaconine biosynthesis.…”

Section: Introductionmentioning

confidence: 99%

GLYCOALKALOID METABOLISM1 Is Required for Steroidal Alkaloid Glycosylation and Prevention of Phytotoxicity in Tomato

et al. 2011

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Steroidal alkaloids (SAs) are triterpene-derived specialized metabolites found in members of the Solanaceae family that provide plants with a chemical barrier against a broad range of pathogens. Their biosynthesis involves the action of glycosyltransferases to form steroidal glycoalkaloids (SGAs). To elucidate the metabolism of SGAs in the Solanaceae family, we examined the tomato (Solanum lycopersicum) GLYCOALKALOID METABOLISM1 (GAME1) gene. Our findings imply that GAME1 is a galactosyltransferase, largely performing glycosylation of the aglycone tomatidine, resulting in SGA production in green tissues. Downregulation of GAME1 resulted in an almost 50% reduction in a-tomatine levels (the major SGA in tomato) and a large increase in its precursors (i.e., tomatidenol and tomatidine). Surprisingly, GAME1-silenced plants displayed growth retardation and severe morphological phenotypes that we suggest occur as a result of altered membrane sterol levels caused by the accumulation of the aglycone tomatidine. Together, these findings highlight the role of GAME1 in the glycosylation of SAs and in reducing the toxicity of SA metabolites to the plant cell.

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“…Therefore breeders must be mindful of glycoalkaloid levels when using wild species to develop germplasm. Silencing of the gene encoding a sterol alkaloid glycosyltransferase led to almost complete elimination of α-solanine, with a correlated increase in α-chaconine in some lines but not others (McCue et al 2005). …”

Section: Nutritionmentioning

confidence: 99%

Biotech Potatoes in the 21st Century: 20 Years Since the First Biotech Potato

et al. 2015

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Potato is the world's most important vegetable crop, with nearly 400 million tons produced worldwide every year, lending to stability in food supply and socioeconomic impact. In general, potato is an intensively managed crop, requiring irrigation, fertilization, and frequent pesticide applications in order to obtain the highest yields possible. Important traits are easy to find in wild relatives of potato, but their introduction using traditional breeding can take 15-20 years. This is due to sexual incompatibility between some wild and cultivated species, a desire to remove undesirable wild species traits from adapted germplasm, and difficulty in identifying broadly applicable molecular markers. Fortunately, potato is amenable to propagation via tissue culture and it is relatively easy to introduce new traits using currently available biotech transformation techniques. For these reasons, potato is arguably the crop that can benefit most by modern biotechnology. The benefits of biotech potato, such as limited gene flow to conventionally grown crops and weedy relatives, the opportunity for significant productivity and nutritional quality gains, and reductions in production cost and environmental impact, have the potential to influence the marketability of newly developed varieties. In this review we will discuss current and past efforts to develop biotech potato varieties, traits that could be impacted, and the potential effects that biotech potato could have on the industry.Resumen La papa es el cultivo hortícola más importante en el mundo, con cerca de 400 millones de toneladas producidas a nivel mundial anualmente, acreditando la estabilidad en el suministro de alimentos e impacto socioeconómico. En general, la papa es un cultivo manejado intensivamente, que requiere riego, fertilización y aplicaciones frecuentes de plaguicidas para obtener los más altos rendimientos posibles. Los caracteres importantes son fáciles de encontrar en parientes silvestres de la papa, pero su introducción usando el mejoramiento tradicional puede llevar de 15 a 20 años. Esto es debido a la incompatibilidad sexual entre algunas especies silvestres y cultivadas, el deseo para eliminar características indeseables de las especies silvestres del germoplasma adaptado, y la dificultad en la identificación de marcadores moleculares aplicables ampliamente. Afortunadamente, la papa es receptiva a la propagación por cultivo de tejidos y es relativamente fácil la introducción de nuevos caracteres usando técnicas biotecnológicas de transformación actualmente disponibles. Por estas razones, la papa es probablemente el cultivo que se puede beneficiar mayormente por la biotecnología moderna. Los beneficios de la papa biotecnológica, como el flujo genético limitado a cultivos que se siembran convencionalmente y a los parientes como malezas, la oportunidad para productividad significativa y logros en calidad nutricional, y las reducciones en los costos de producción e impacto ambiental, tienen el potencial para influenciar la comercialización...

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Metabolic compensation of steroidal glycoalkaloid biosynthesis in transgenic potato tubers: using reverse genetics to confirm the in vivo enzyme function of a steroidal alkaloid galactosyltransferase

Cited by 100 publications

References 25 publications

The Sg-1 Glycosyltransferase Locus Regulates Structural Diversity of Triterpenoid Saponins of Soybean

The Sg-1 Glycosyltransferase Locus Regulates Structural Diversity of Triterpenoid Saponins of Soybean

GLYCOALKALOID METABOLISM1 Is Required for Steroidal Alkaloid Glycosylation and Prevention of Phytotoxicity in Tomato

Biotech Potatoes in the 21st Century: 20 Years Since the First Biotech Potato

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