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Concept: Potato

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 To determine whether higher intake of baked or boiled potatoes, French fries, or potato chips is associated with incidence of hypertension.

Concepts: Potato, Potato chip, French fries

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Vegetables are important sources of dietary fiber, vitamins and minerals in the diets of children. The United States Department of Agriculture (USDA) National School Lunch Program has new requirements for weekly servings of vegetable subgroups as well as beans and peas. This study estimated the cost impact of meeting the USDA requirements using 2008 national prices for 98 vegetables, fresh, frozen, and canned. Food costs were calculated per 100 grams, per 100 calories, and per edible cup. Rank 6 score, a nutrient density measure was based on six nutrients: dietary fiber; potassium; magnesium; and vitamins A, C, and K. Individual nutrient costs were measured as the monetary cost of 10% daily value of each nutrient per cup equivalent. ANOVAs with post hoc tests showed that beans and starchy vegetables, including white potatoes, were cheaper per 100 calories than were dark-green and deep-yellow vegetables. Fresh, frozen, and canned vegetables had similar nutrient profiles and provided comparable nutritional value. However, less than half (n = 46) of the 98 vegetables listed by the USDA were were consumed >5 times by children and adolescents in the 2003-4 National Health and Nutrition Examination Survey database. For the more frequently consumed vegetables, potatoes and beans were the lowest-cost sources of potassium and fiber. These new metrics of affordable nutrition can help food service and health professionals identify those vegetable subgroups in the school lunch that provide the best nutritional value per penny.

Concepts: Nutrition, Nutrient, Vitamin, Essential nutrient, Vegetable, Dietary fiber, Potato, National School Lunch Act

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Pest and pathogen losses jeopardise global food security and ever since the 19(th) century Irish famine, potato late blight has exemplified this threat. The causal oomycete pathogen, Phytophthora infestans, undergoes major population shifts in agricultural systems via the successive emergence and migration of asexual lineages. The phenotypic and genotypic bases of these selective sweeps are largely unknown but management strategies need to adapt to reflect the changing pathogen population. Here, we used molecular markers to document the emergence of a lineage, termed 13_A2, in the European P. infestans population, and its rapid displacement of other lineages to exceed 75% of the pathogen population across Great Britain in less than three years. We show that isolates of the 13_A2 lineage are among the most aggressive on cultivated potatoes, outcompete other aggressive lineages in the field, and overcome previously effective forms of plant host resistance. Genome analyses of a 13_A2 isolate revealed extensive genetic and expression polymorphisms particularly in effector genes. Copy number variations, gene gains and losses, amino-acid replacements and changes in expression patterns of disease effector genes within the 13_A2 isolate likely contribute to enhanced virulence and aggressiveness to drive this population displacement. Importantly, 13_A2 isolates carry intact and in planta induced Avrblb1, Avrblb2 and Avrvnt1 effector genes that trigger resistance in potato lines carrying the corresponding R immune receptor genes Rpi-blb1, Rpi-blb2, and Rpi-vnt1.1. These findings point towards a strategy for deploying genetic resistance to mitigate the impact of the 13_A2 lineage and illustrate how pathogen population monitoring, combined with genome analysis, informs the management of devastating disease epidemics.

Concepts: Gene, Genetics, Potato, Oomycete, Phytophthora infestans, Great Famine, Potatoes, Phytophthora

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Modulation of the malate content of tomato (Solanum lycopersicum) fruit by altering the expression of mitochondrially localized enzymes of the tricarboxylic acid cycle resulted in enhanced transitory starch accumulation and subsequent effects on postharvest fruit physiology. In this study, we assessed whether such a manipulation would similarly affect starch biosynthesis in an organ that displays a linear, as opposed to a transient, kinetic of starch accumulation. For this purpose, we used RNA interference to down-regulate the expression of fumarase in potato (Solanum tuberosum) under the control of the tuber-specific B33 promoter. Despite displaying similar reductions in both fumarase activity and malate content as observed in tomato fruit expressing the same construct, the resultant transformants were neither characterized by an increased flux to, or accumulation of, starch, nor by alteration in yield parameters. Since the effect in tomato was mechanistically linked to derepression of the reaction catalyzed by ADP-glucose pyrophosphorylase, we evaluated whether the lack of effect on starch biosynthesis was due to differences in enzymatic properties of the enzyme from potato and tomato or rather due to differential subcellular compartmentation of reductant in the different organs. The results are discussed in the context both of current models of metabolic compartmentation and engineering.

Concepts: Metabolism, Adenosine triphosphate, Enzyme, Starch, Tomato, Solanaceae, Solanum, Potato

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Phytophthora infestans, the cause of potato late blight, is infamous for having triggered the Irish Great Famine in the 1840s. Until the late 1970s, P. infestans diversity outside of its Mexican center of origin was low, and one scenario held that a single strain, US-1, had dominated the global population for 150 years; this was later challenged based on DNA analysis of historical herbarium specimens. We have compared the genomes of 11 herbarium and 15 modern strains. We conclude that the 19th century epidemic was caused by a unique genotype, HERB-1, that persisted for over 50 years. HERB-1 is distinct from all examined modern strains, but it is a close relative of US-1, which replaced it outside of Mexico in the 20th century. We propose that HERB-1 and US-1 emerged from a metapopulation that was established in the early 1800s outside of the species' center of diversity. DOI:http://dx.doi.org/10.7554/eLife.00731.001.

Concepts: DNA, Potato, Oomycete, Phytophthora infestans, Overpopulation, Great Famine, Potatoes, Phytophthora

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Background: Few studies have assessed the association between potato consumption and mortality.Objective: We investigated whether potato consumption (including fried and unfried potatoes) is associated with increased premature mortality risk in a North American cohort.Design: A longitudinal analysis included 4440 participants aged 45-79 y at baseline with an 8-y follow-up from the Osteoarthritis Initiative cohort study. Potato consumption (including fried and unfried potatoes) was analyzed by using a Block Brief 2000 food-frequency questionnaire and categorized as ≤1 time/mo, 2-3 times/mo, 1 time/wk, 2 times/wk, or ≥3 times/wk. Mortality was ascertained through validated cases of death. To investigate the association between potato consumption and mortality, Cox regression models were constructed to estimate HRs with 95% CIs, with adjustment for potential confounders.Results: Of the 4400 participants, 2551 (57.9%) were women with a mean ± SD age of 61.3 ± 9.2 y. During the 8-y follow-up, 236 participants died. After adjustment for 14 potential baseline confounders, and taking those with the lowest consumption of potatoes as the reference group, participants with the highest consumption of potatoes did not show an increased risk of overall mortality (HR: 1.11; 95% CI: 0.65, 1.91). However, subgroup analyses indicated that participants who consumed fried potatoes 2-3 times/wk (HR: 1.95; 95% CI: 1.11, 3.41) and ≥3 times/wk (HR: 2.26; 95% CI: 1.15, 4.47) were at an increased risk of mortality. The consumption of unfried potatoes was not associated with an increased mortality risk.Conclusions: The frequent consumption of fried potatoes appears to be associated with an increased mortality risk. Additional studies in larger sample sizes should be performed to confirm if overall potato consumption is associated with higher mortality risk. This trial was registered at clinicaltrials.gov as NCT00080171.

Concepts: Regression analysis, Cohort study, Longitudinal study, Epidemiology, Clinical trial, Actuarial science, Potato, French fries

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Potato (Solanum tuberosum L.) is the third most widely consumed plant food by humans. Its tubers are rich in starch and vitamin C, but have low or null levels of essential nutrients such as provitamin A and vitamin E. Transformation of potato with a bacterial mini-pathway for β-carotene in a tuber-specific manner results in a “golden” potato (GP) tuber phenotype resulting from accumulation of provitamin A carotenoids (α- and β-carotene) and xanthophylls. Here, we investigated the bioaccessibility of carotenoids and vitamin E as α-tocopherol (αTC) in boiled wild type and golden tubers using in vitro digestion. Golden tubers contained up to 91 μg provitamin A carotenes (PAC)/g D, increased levels of xanthophylls, phytoene and phytofluene, as well as up to 78 μg vitamin E/g DW. Cubes from wild type and GP tubers were boiled and subjected to simulated digestion to estimate bioaccessibility of carotenoids and αTC. Retention in boiled GPs exceeded 80% for β-carotene (βC), α-carotene (αC), lutein, phytoene ± and αTC, but less than 50% for phytofluene. The efficiency of partitioning of total βC, αC, E-lutein, phytoene, phytofluene and αTC in the mixed micelle fraction during small intestinal digestion was influenced by genotype, tuber content and hydrophobicity. Apical uptake of the compounds that partitioned in mixed micelles by monolayers of human intestinal Caco-2 cells during incubation for 4h was 14-20% for provitamin A and xanthophylls, 43-45% for phytoene, 23-27% for phytofluene, and 53% for αTC. These results suggest that a 150 g serving of boiled golden potatoes has the potential to contribute 42% and 23% of the daily requirement of retinol activity equivalents (RAE), as well as 34 and 17% of the daily vitamin E requirement for children and women of reproductive age, respectively.

Concepts: Antioxidant, Vitamin, Carotenoid, Vitamin C, Solanum, Potato, Carotene, Vitamin A

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BACKGROUND: Strategies that may increase compliance to reduced energy intakes are needed to reduce the health burden of obesity. Conflicting evidence exists regarding the effects of snacking on satiety and energy intake. METHODS: This study compared short-term satiety from two common snack foods, low fat popcorn or potato chips. Using a counterbalanced within-subject design, 35 normal weight non-smoking participants (17 men, 18 women) ages 20–50 years (mean age 33 +/- 11, BMI 23 +/- 2 kg/m2) consumed four conditions each: 200 mL of water (control), one cup (4 g, 15 kcal) popcorn, 6 cups (27 g, 100 kcal) popcorn, and one cup (28 g, 150 kcal) potato chips, each with 200 mL water. Participants rated their hunger, satisfaction, prospective consumption, and thirst on 100 mm visual analogue scales 30 minutes after commencement of snack consumption. In addition, post-snack energy intake from an ad libitum meal (amount served less amount remaining) was measured, and the test food and meal combined energy intake and energy compensation were calculated. RESULTS: Participants expressed less hunger, more satisfaction, and lower estimates of prospective food consumption after six cups of popcorn compared to all other treatments (P < 0.05). Energy compensation was 220% +/- 967%, 76% +/- 143% and 42% +/- 75% after one cup popcorn, six cups popcorn and one cup potato chips, respectively. Combined energy intake was significantly greater (P < 0.01) during the potato chips condition (803 +/- 277 kcal) compared to control (716 +/- 279 kcal) or popcorn conditions (698 +/- 286 kcal for one cup and 739 +/- 294 kcal for six cups). Combined energy intakes from both popcorn conditions were not significantly different than control (p > 0.05). CONCLUSION: Popcorn exerted a stronger effect on short-term satiety than did potato chips as measured by subjective ratings and energy intake at a subsequent meal. This, combined with its relatively low calorie load, suggests that whole grain popcorn is a prudent choice for those wanting to reduce feelings of hunger while managing energy intake and ultimately, body weight.

Concepts: Food, Potato, Snack foods, Snack food, Meal, Calorie, Potato chip, Popcorn

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Cultivated potatoes (Solanum tuberosum L.), domesticated from wild Solanum species native to the Andes of southern Peru, possess a diverse gene pool representing more than 100 tuber-bearing relatives (Solanum section Petota). A diversity panel of wild species, landraces, and cultivars was sequenced to assess genetic variation within tuber-bearing Solanum and the impact of domestication on genome diversity and identify key loci selected for cultivation in North and South America. Sequence diversity of diploid and tetraploid Stuberosum exceeded any crop resequencing study to date, in part due to expanded wild introgressions following polyploidy that captured alleles outside of their geographic origin. We identified 2,622 genes as under selection, with only 14-16% shared by North American and Andean cultivars, showing that a limited gene set drove early improvement of cultivated potato, while adaptation of upland (Stuberosum group Andigena) and lowland (S. tuberosum groups Chilotanum and Tuberosum) populations targeted distinct loci. Signatures of selection were uncovered in genes controlling carbohydrate metabolism, glycoalkaloid biosynthesis, the shikimate pathway, the cell cycle, and circadian rhythm. Reduced sexual fertility that accompanied the shift to asexual reproduction in cultivars was reflected by signatures of selection in genes regulating pollen development/gametogenesis. Exploration of haplotype diversity at potato’s maturity locus (StCDF1) revealed introgression of truncated alleles from wild species, particularly Smicrodontum in long-day-adapted cultivars. This study uncovers a historic role of wild Solanum species in the diversification of long-day-adapted tetraploid potatoes, showing that extant natural populations represent an essential source of untapped adaptive potential.

Concepts: DNA, Gene, Genetics, Evolution, Species, Solanum, Potato, Andes

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Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight, was responsible for the Irish potato famine of the 1840s. Initial disease outbreaks occurred in the US in 1843, two years prior to European outbreaks. We examined the evolutionary relationships and source of the 19th-century outbreaks using herbarium specimens of P. infestans from historic (1846-1970) and more recent isolates (1992-2014) of the pathogen. The same unique SSR multilocus genotype, named here as FAM-1, caused widespread outbreaks in both US and Europe. The FAM-1 lineage shared allelic diversity and grouped with the oldest specimens collected in Colombia and Central America. The FAM-1 lineage of P. infestans formed a genetic group that was distinct from more recent aggressive lineages found in the US. The US-1 lineage formed a second, mid-20th century group. Recent modern US lineages and the oldest Mexican lineages formed a genetic group with recent Mexican lineages, suggesting a Mexican origin of recent US lineages. A survey of mitochondrial haplotypes in a larger set of global herbarium specimens documented the more frequent occurrence of the HERB-1 (type Ia) mitochondrial haplotype in archival collections from 1866-75 and 1906-1915 and the rise of the Ib mitochondrial lineage (US-1) between 1946-1955. The FAM-1 SSR lineage survived for almost 100 years in the US, was geographically widespread, and was displaced first in the mid-20th century by the US-1 lineage and then by distinct new aggressive lineages that migrated from Mexico.

Concepts: Evolution, Potato, Plant pathogens and diseases, Oomycete, Phytophthora infestans, Great Famine, Potatoes, Phytophthora