Genetic and environmental control of potato glycoalkaloids

Sinden, S. L.; Sanford, L. L.; Webb, R. E.

doi:10.1007/bf02854035

Cited by 108 publications

(71 citation statements)

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“…Characterization of the inheritance of specific SGAs and SGA content has been limited, despite the importance of these phytochemicals (Valkonen et al, 1996;Ginzberg et al, 2009;Manrique-Carpintero et al, 2014). The SGA content of most commercial varieties of potato tubers is well below the human safety limit (200 mg/kg fresh weight), and a high SGA content is frequently associated with the introduction of wild germplasm to the breeding program (Sinden et al, 1984). Our results open the way for breeding of SGAfree potatoes.…”

Section: The Phenotype Of Pga1-and Pga2-knockdown Transgenic Potato Pmentioning

confidence: 81%

Two Cytochrome P450 Monooxygenases Catalyze Early Hydroxylation Steps in the Potato Steroid Glycoalkaloid Biosynthetic Pathway

et al. 2016

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Solanine and a-chaconine, steroidal glycoalkaloids (SGAs) found in potato (Solanum tuberosum), are among the best-known secondary metabolites in food crops. At low concentrations in potato tubers, SGAs are distasteful; however, at high concentrations, SGAs are harmful to humans and animals. Here, we show that POTATO GLYCOALKALOID BIOSYNTHESIS1 (PGA1) and PGA2, two genes that encode cytochrome P450 monooxygenases (CYP72A208 and CYP72A188), are involved in the SGA biosynthetic pathway, respectively. The knockdown plants of either PGA1 or PGA2 contained very little SGA, yet vegetative growth and tuber production were not affected. Analyzing metabolites that accumulated in the plants and produced by in vitro enzyme assays revealed that PGA1 and PGA2 catalyzed the 26-and 22-hydroxylation steps, respectively, in the SGA biosynthetic pathway. The PGA-knockdown plants had two unique phenotypic characteristics: The plants were sterile and tubers of these knockdown plants did not sprout during storage. Functional analyses of PGA1 and PGA2 have provided clues for controlling both potato glycoalkaloid biosynthesis and tuber sprouting, two traits that can significantly impact potato breeding and the industry.

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Section: The Phenotype Of Pga1-and Pga2-knockdown Transgenic Potato Pmentioning

confidence: 81%

Two Cytochrome P450 Monooxygenases Catalyze Early Hydroxylation Steps in the Potato Steroid Glycoalkaloid Biosynthetic Pathway

et al. 2016

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“…There is no information in the available literature regarding the effect of biostimulants on the glycoalkaloid accumulation in potato tubers. However, there are many mentions in the literature confirming the fact that TGA in tubers increase due to stress conditions during the growing season; that is too low or too high temperature, prolonged cold or heat conditions, water shortage or excess and strong sunlight (Sinden et al 1984, Bejarano et al 2000, Hamouz et al 2014). The present study demonstrated that the highest concentration of glycoalkaloids, on average 93.76 mg/kg fresh matter, was in 2012 when lowest precipitation in the growing season was accompanied by the highest average air temperature.…”

Section: Resultsmentioning

confidence: 99%

The effect of biostimulants and herbicides on glycoalkaloid accumulation in potato

Gugała¹,

Zarzecka²,

Dołęga³

et al. 2016

Plant Soil Environ.

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The objective of the study was to determine the effect of biostimulants and herbicides on the level of glycoalkaloids in leaves and tubers of three table potato cultivars. The following factors were examined: I -potato cultivars: Bartek, Gawin, Honorata; II -five weed control methods (application of biostimulants and herbicides: 1. mechanical weed control -control treatment and four herbicide or herbicide + biostimulant treatments (Harrier 295 ZC, Harrier 295 ZC + Kelpak SL, Sencor 70 WG, Sencor 70 WG + Asahi SL). The potato tuber content of glycoalkaloids was significantly affected by genotype. The highest total glycoalkaloid (TGA) content was determined in cv. Bartek tubers and the lowest in cv. Honorata tubers, on average 92.31 and 91.14 mg/kg fresh matter, respectively. Herbicides applied alone or in combination with biostimulants contributed to an increase in glycoalkaloids determined in both potato leaves and tubers, compared with the control. However, a significantly higher TGA content was found following the application of Harrier 295 ZC only.Keywords: plant resistance; toxicity; weather conditions; tuberous crop; Solanum tuberosum L. 256Vol. 62, 2016, No. 6: 256-260 Plant Soil Environ. Field studies were conducted in soils representing the following type of agricultural land: grey brown podzolic soil of ploughed fields belonging to agronomic category I, the order of brown soils, quality class IVb which represents the rye very good class of agricultural suitability. In 2012 and 2013, soil pH was slightly acidic (5.60) whereas in 2014 it was alkaline (7.35). The organic matter content ranged from 15.0-18.7 g/kg. The available phosphorus (P) content ranged from high to very high, available potassium (K) content ranged from average to very high, and available magnesium (Mg) content was high. Winter wheat crops preceded table potato in each study year. The same organic manuring and mineral fertilisation were applied: 25 t/ha farmyard manure as well as 100 kg/ha N, 44 kg P/ha and 125 kg K/ha. Samples of potato leaves (10 leaves) for chemical analyses were taken during the flowering stage. Potato tuber samples (50 tubers) were collected from the plots during harvest and stored at 10-12°C. Chemical analyses of fresh material were performed so as to obtain three replicates. Glycoalkaloid contents of potato leaves and tubers were determined following the Bergers' method (Bergers 1980). Results of the study were analysed by ANOVA. Significance of sources of variation was checked with the Fisher-Snedecor test and the significance of differences between means was tested using the multiple comparison Tukey's test at the significance level of P = 0.05. Statistical calculations were performed in Excel using own algorithm based on the mathematical model. Values of the Sielianinov's hydrothermal coefficient (K = 0.95) indicate that the year 2012 was slightly dry (Table 1). The precipitation sum amounted to 264.9 mm and was by 10.6 mm lower than the long-term mean whereas the average temperature over the growing...

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“…Регуляция синтеза гликоал-колоидов зависит не только от генотипа, но и от действия внешних факторов (Sinden et al, 1984). Прохладный и влажный климат, различный стресс, поранения, а также экспозиция клубней на свету повышают уровень гликоал-калоидов в растениях (Smith et al, 1996).…”

Section: регуляция биосинтеза сгаunclassified

“…Информация о наличии транспорта СГА в растениях картофеля отсутствует (Smith et al, 1996;Friedman, 2006;Alyokhin et al, 2012). В связи с этим высказано предполо-жение, что основной биосинтез СГА в клубнях также про-исходит в феллодерме (Sinden et al, 1984;Alyokhin et al, 2012). Высокий уровень СГА в феллодерме коррелировал с высоким уровнем транскрипции ключевых ферментов биосинтеза СГА, в то время как в других частях растения наблюдали низкий уровень и СГА, и транскриптов генов биосинтеза СГА (Krits et al, 2007).…”

Section: метаболизм сга и распределение в растительных тканяхunclassified

The Biosynthesis Regulation of Potato Steroidal Glycoalkaloids

Ivanova¹,

Gerasimova²,

Хлесткина³

2018

Vestn. VOGiS

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Potato steroidal glycoalkaloids (SGAs) compose a part of plant immunity. Some of their modified variants are toxic to humans. In the course of potato domestication, plants with a lower SGA level were selected. The advent of approaches for manipulation with the regulation of metabolic pathways provides an opportunity to overcome the undesirable direct relationship between the potato resistance to pests and the toxicity of its tubers. However, for such a fine regulation, a deep knowledge of the regulatory network of potato SGA biosynthesis is required. The purpose of this review is to summarize the information on the known SGA biosynthesis genes in plants and the results of the investigation of these genes in potato, as well as to consider the mechanisms of the SGA protective toxic action against pathogens and pests. The SGA biosynthesis is realized via the cytosolic mevalonate pathway and consists of three stages. The first two stages are required for the synthesis of primary metabolites, and lead to cycloartanol and cholesterol, respectively. Twelve enzymes are involved in the biosynthesis, and the half of them are involved in the biosynthesis of phytosterols, which is a branch of the first stage of this metabolic pathway. In the potato leaves with an excess of phytosterols, the synthesis switches to SGAs, increasing the content of the latter. In tubers, with an excess of SGA precursors, they are involved in the synthesis of lanosterol, supporting in this way the stable level of SGA. The importance of structural genes encoding the enzymes of the first two stages of biosynthesis does not allow us to consider them as a target for knockout in order to reduce the level of SGAs. However, information about the tissue-specific mechanisms of switching between the pathways of synthesis of SGA and other compounds having common precursors with SGAs can be used to manipulate the tissue-specific level of steroidal glycoalkaloids. At the third stage (the synthesis of glycoalkaloids from cholesterol), about 20 enzymes participate. In the potato genome, 14 corresponding genes were identified, 8 of which were studied in detail using reverse genetics approaches. As a promising target for reducing SGA levels in tubers, the genes encoding PGA enzymes (belonging to the CYP72 subfamily cytochrome-P450-dependent monooxygenases catalyzing the conversion of hydrocholesterol to trihydrocholesterol) and SGT (SGA glycosyltransferases that catalyze the conversion of solanidine to its toxic glycosylated derivatives α-solanine and α-chaconine) are considered. Cis-regulatory elements in the promoter regions of some glycoalkaloid biosynthesis genes, including elements responsible for tissue-specific expression, Стероидные гликоалкалоиды (СГА) картофеля составляют часть иммунитета растений. Некоторые их модифицированные фор-мы токсичны для человека. В ходе доместикации картофеля происходил отбор растений с пониженным уровнем СГА. В на-стоящее время с появлением методов, при помощи которых возможно специфично влиять на регуляцию метаболических пу...

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Genetic and environmental control of potato glycoalkaloids

Cited by 108 publications

References 44 publications

Two Cytochrome P450 Monooxygenases Catalyze Early Hydroxylation Steps in the Potato Steroid Glycoalkaloid Biosynthetic Pathway

Two Cytochrome P450 Monooxygenases Catalyze Early Hydroxylation Steps in the Potato Steroid Glycoalkaloid Biosynthetic Pathway

The effect of biostimulants and herbicides on glycoalkaloid accumulation in potato

The Biosynthesis Regulation of Potato Steroidal Glycoalkaloids

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