Validation of overweight children's fruit and vegetable intake using plasma carotenoids

Assessing dietary intake in children is difficult and limited validated tools exist. Plasma carotenoids are nutritional biomarkers of fruit and vegetable intake and therefore suitable to validate reported dietary intakes. The aim of this study was to examine the comparative validity of a food frequency questionnaire (FFQ), completed by parents reporting child fruit and vegetable intake compared to plasma carotenoid concentrations. A sample of children aged 5-12 years (n = 93) from a range of weight categories were assessed. Dietary intake was measured using a 137-item semi-quantitative FFQ. Plasma carotenoids were measured using reverse phase high-performance liquid chromatography. Pearson correlation coefficients between reported dietary intake of carotenoids and plasma carotenoid concentrations were strongest after adjustment for BMI (beta-carotene (r = 0.56, P < 0.05), alpha-carotene (r = 0.51, P < 0.001), cryptoxanthin (r = 0.32, P < 0.001)). Significantly lower levels (P < 0.05) of all plasma carotenoids, except lutein, were found among overweight and obese children when compared to healthy weight children. Parental report of children's carotenoid intakes, using a FFQ can be used to provide a relative validation of fruit and vegetable intake. The lower plasma carotenoid concentrations found in overweight and obese children requires further investigation.     

A golden era—pro-vitamin A enhancement in diverse crops

Numerous crops have been bred or engineered to increase carotenoid levels in an effort to develop novel strategies that address vitamin A deficiency in the developing world. The pioneering work in rice (not covered in this review) has been followed up in many additional crops, some of which are staples like rice whereas others are luxury products whose impact on food security is likely to be marginal. This review surveys the progress that has been made in carotenoid breeding and metabolic engineering, focusing on β-carotene enhancement in crops other than rice. We ask if these efforts have the potential to address vitamin A deficiency in developing countries by comparing bioavailable pro-vitamin A levels in wild type and enhanced crops to determine whether nutritional requirements can be met without the consumption of unrealistic amounts of food. The potential impact of carotenoid enhancement should therefore be judged against benchmarks that include the importance of particular crops in terms of global food security, the amount of bioavailable β-carotene, and the amount of food that must be consumed to achieve the reference daily intake of vitamin A.     

Differences in carotenoid accumulation among three feeder-cricket species: implications for carotenoid delivery to captive insectivores

There are a limited number of feeder-invertebrates available to feed captive insectivores, and many are deficient in certain nutrients. Gut-loading is used to increase the diversity of nutrients present in the captive insectivore diet; however, little is known about delivery of carotenoids via gut-loading. Carotenoids may influence health and reproduction due to their roles in immune and antioxidant systems. We assessed interspecific variation in carotenoid accumulation and retention in three feeder-cricket species (Gryllus bimaculatus, Gryllodes sigillatus and Acheta domesticus) fed one of three diets (wheat-bran, fish-food based formulated diet, and fresh fruit and vegetables). Out of the three species of feeder-cricket in the fish-food-based dietary treatment group, G. bimaculatus had the greatest total carotenoid concentration. All cricket species fed the wheat-bran diet had very low carotenoid concentrations. Species on the fish-food-based diet had intermediate carotenoid concentrations, and those on the fruit and vegetable diet had the highest concentrations. Carotenoid retention was poor across all species. Overall, this study shows that, by providing captive insectivores with G. bimaculatus crickets recently fed a carotenoid-rich diet, the quantity of carotenoids in the diet can be increased.     

Salt Tolerance in Selected Vegetable Crops

Ensuring adequate food production is a major issue in the context of an increasing human population, limit to the areas of new land that can be cultivated, and loss of existing cultivated lands to abiotic stresses. Of these stresses, salinity consistently has the greatest impact in reducing the area of cultivated land, often due to inappropriate irrigation techniques. To increase food supply, there is a need to produce salt-tolerant crops, which can grow successfully on salt-affected lands. Among crops, vegetables possess a central position in the human diet because of their nutritional value providing vitamins, carbohydrates, proteins, and mineral nutrients. There are many vegetable crops of local importance around the world but others that are very widely cultivated. All of these vegetable crops are affected by salinity more or less severely. Salinity affects every aspect of vegetable crop development including their morphology, physiological function and yield. Although efforts have been made to understand the mechanisms of salt tolerance in vegetable crops, less attention has been paid to these than to the staple crops. Where attempts have been made to improve salt tolerance of vegetables, the strategies have ranged from exogenous application of fertilizers, compatible solutes or plant growth regulators, to use of advanced molecular techniques for genetic modifications. This review focuses on the responses of pea, okra, tomato, eggplant, pepper, carrot, broccoli, cauliflower, and potato to salt stress and the strategies being used to enhance their salt tolerance.     

Metabolic engineering of carotenoid accumulation by creating a metabolic sink

Carotenoids are highly beneficial for human nutrition and health because they provide essential nutrients and important antioxidants in our diets. However, many food crops, especially the major staple crops contain only trace to low amounts of carotenoids. Although significant progress has been made in developing food crops rich in carotenoids by altering the expression of carotenoid biosynthetic genes, in many cases it has proved to be difficult to reach the desired levels of carotenoid enrichment. The recent identification and characterization of a novel gene mutation in cauliflower reveals that creating a metabolic sink to sequester carotenoids is an important mechanism to control carotenoid accumulation in plants. The successful demonstration of increased carotenoid accumulation in association with the formation of sink structures in transgenic crops offers a new and alternative approach to increase carotenoid content. Manipulation of the formation of metabolic sink along with the catalytic activity of the pathway may represent a promising strategy for maximally improving the nutritional quality of food crops.     

Vegetable crop irrigation with tertiary filtered municipal wastewater

Abstract

The use of tertiary membrane-filtered municipal wastewater for irrigation as an alternative to natural freshwater sources was evaluated. Membrane filtration was considered as a viable technology to reclaim wastewater for irrigation, and the microbial and heavy metal impact on crops and soil was studied. The results of 2 years of research (2003 – 2004), carried out in Cerignola in the South of Italy, are reported. Tertiary treatment was carried out using a membrane filtration pilot plant with a hollow fibre submerged system. The water produced was used for drip irrigation of three vegetable crops in succession – processing tomato, fennel and lettuce – and compared with conventional water. Microbiological analyses were performed on the water used for irrigation, on soil samples and on marketable crops. Results show that the microbial content of soil and crops did not show relevant differences in relation to the two types of water. The measured values of heavy metals concentration in crops never exceeded toxic values. The filtered wastewater never caused an increase of bacterial concentration in the soil nor on the edible part of crops. Therefore, tertiary filtered municipal wastewater can be considered a valid alternative source of water for vegetable crop irrigation.     

Plasma carotenoid concentrations of incubating American kestrels (Falco sparverius) show annual,seasonal, and individual variation and explain reproductive outcome

In wild birds, the proximate and ultimate factors that affect circulating carotenoid concentrations remain poorly understood. We studied variation in plasma carotenoid concentrations across several scales: annual, seasonal, pair, territory and individual, and evaluated whether plasma carotenoid concentrations explained reproductive outcome of wild American kestrels (Falco sparverius). We sampled plasma carotenoid concentrations of 99 female and 80 male incubating kestrels from April to June in 2008 to 2012. Plasma carotenoid concentrations were explained by an interaction between year and sex, date, and random effects for pair and individual identity. In general, plasma carotenoid concentrations of males were significantly higher than females, but this depended on year. Within a breeding season, earlier nesting kestrels had higher carotenoid concentrations than later nesting kestrels, a pattern that is coincident with seasonal trends in local fitness. Pair and individual identity explained variation in carotenoid concentrations suggesting that carotenoid concentrations of mated birds were correlated, and some individuals consistently maintained higher carotenoid levels than others. Male carotenoid concentrations were positively associated with number of young fledged per pair. These results are consistent with the hypothesis that higher quality individuals have higher carotenoid levels compared to lower quality individuals, despite annual variations in carotenoid availability.     

Vegetable biology and breeding in the genomics era

Vegetable crops provide a rich source of essential nutrients for humanity and represent critical economic values to global rural societies. However, genetic studies of vegetable crops have lagged behind major food crops, such as rice, wheat and maize, thereby limiting the application of molecular breeding. In the past decades, genome sequencing technologies have been increasingly applied in genetic studies and breeding of vegetables. In this review, we recapitulate recent progress on reference genome construction, population genomics and the exploitation of multi-omics datasets in vegetable crops. These advances have enabled an in-depth understanding of their domestication and evolution, and facilitated the genetic dissection of numerous agronomic traits, which jointly expedites the exploitation of state-of-the-art biotechnologies in vegetable breeding. We further provide perspectives of further directions for vegetable genomics and indicate how the ever-increasing omics data could accelerate genetic, biological studies and breeding in vegetable crops.

     

Effect of the food production chain from farm practices to vegetable processing on outbreak incidence

The popularity in the consumption of fresh and fresh-cut vegetables continues to increase globally. Fresh vegetables are an integral part of a healthy diet, providing vitamins, minerals, antioxidants and other health-promoting compounds. The diversity of fresh vegetables and packaging formats (spring mix in clamshell container, bagged heads of lettuce) support increased consumption. Unfortunately, vegetable production and processing practices are not sufficient to ensure complete microbial safety. This review highlights a few specific areas that require greater attention and research. Selected outbreaks are presented to emphasize the need for science-based ‘best practices’. Laboratory and field studies have focused on inactivation of pathogens associated with manure in liquid, slurry or solid forms. As production practices change, other forms and types of soil amendments are being used more prevalently. Information regarding the microbial safety of fish emulsion and pellet form of manure is limited. The topic of global climate change is controversial, but the potential effect on agriculture cannot be ignored. Changes in temperature, precipitation, humidity and wind can impact crops and the microorganisms that are associated with production environments. Climate change could potentially enhance the ability of pathogens to survive and persist in soil, water and crops, increasing human health risks. Limited research has focused on the prevalence and behaviour of viruses in pre and post-harvest environments and on vegetable commodities. Globally, viruses are a major cause of foodborne illnesses, but are seldom tested for in soil, soil amendments, manure and crops. Greater attention must also be given to the improvement in the microbial quality of seeds used in sprout production. Human pathogens associated with seeds can result in contamination of sprouts intended for human consumption, even when all appropriate ‘best practices’ are used by sprout growers.     

The vegetable SNP database: An integrated resource for plant breeders and scientists

Single nucleotide polymorphisms (SNPs) are widely used in genetic research and molecular breeding. To date, the genomes of many vegetable crops have been assembled, and hundreds of core germplasms for each vegetable have been sequenced. However, these data are not currently easily accessible because they are stored on different public databases. Therefore, a vegetable crop SNP database should be developed that hosts SNPs demonstrated to have a high success rate in genotyping for genetic research (herein, “alpha SNPs”). We constructed a database (VegSNPDB, http://www.vegsnpdb.cn/) containing the sequence data of 2032 germplasms from 16 vegetable crop species. VegSNPDB hosts 118,725,944 SNPs of which 4,877,305 were alpha SNPs. SNPs can be searched by chromosome number, position, SNP type, genetic population, or specific individuals, as well as the values of MAF, PIC, and heterozygosity. We hope that VegSNPDB will become an important SNP database for the vegetable research community.     

Validation model for Raman based skin carotenoid detection

Raman spectroscopy holds promise as a rapid objective non-invasive optical method for the detection of carotenoid compounds in human tissue in vivo. Carotenoids are of interest due to their functions as antioxidants and/or optical absorbers of phototoxic light at deep blue and near UV wavelengths. In the macular region of the human retina, carotenoids may prevent or delay the onset of age-related tissue degeneration. In human skin, they may help prevent premature skin aging, and are possibly involved in the prevention of certain skin cancers. Furthermore, since carotenoids exist in high concentrations in a wide variety of fruits and vegetables, and are routinely taken up by the human body through the diet, skin carotenoid levels may serve as an objective biomarker for fruit and vegetable intake. Before the Raman method can be accepted as a widespread optical alternative for carotenoid measurements, direct validation studies are needed to compare it with the gold standard of high performance liquid chromatography. This is because the tissue Raman response is in general accompanied by a host of other optical processes which have to be taken into account. In skin, the most prominent is strongly diffusive, non-Raman scattering, leading to relatively shallow light penetration of the blue/green excitation light required for resonant Raman detection of carotenoids. Also, sizable light attenuation exists due to the combined absorption from collagen, porphyrin, hemoglobin, and melanin chromophores, and additional fluorescence is generated by collagen and porphyrins. In this study, we investigate for the first time the direct correlation of in vivo skin tissue carotenoid Raman measurements with subsequent chromatography derived carotenoid concentrations. As tissue site we use heel skin, in which the stratum corneum layer thickness exceeds the light penetration depth, which is free of optically confounding chromophores, which can be easily optically accessed for in vivo RRS measurement, and which can be easily removed for subsequent biochemical measurements. Excellent correlation (coefficient R = 0.95) is obtained for this tissue site which could serve as a model site for scaled up future validation studies of large populations. The obtained results provide proof that resonance Raman spectroscopy is a valid non-invasive objective methodology for the quantitative assessment of carotenoid antioxidants in human skin in vivo.     

Integrated Control of Clubroot

Clubroot caused by Plasmodiophora brassicae affects the Brassicaceae family of plants, including many important vegetable and broadacre crops. In the last 20 years increasing intensity of vegetable production and the rapid growth in popularity of oilseed rape as a broadacre or arable break crop have increased the severity of clubroot and the area of land affected in both the vegetable and broadacre industries. Resting spores of P. brassicae are long-lived in soil, but the number of spores can be reduced through crop rotation, fallowing, chemical application, and management of brassica weeds. The host-pathogen system is responsive to a range of control measures, including calcium and boron amendments, manipulation of soil pH, and fungicide application. Molecular tests have been developed to predict disease and resistant cultivars are available for some crops. Increasingly, a multifaceted or integrated approach is being used to manage clubroot. This approach has been particularly successful in vegetable production systems.     

Carotenoid accumulation and function in seeds and non-green tissues

Carotenoids are plant pigments that function as antioxidants, hormone precursors, colourants and essential components of the photosynthetic apparatus. Carotenoids accumulate in nearly all types of plastids, not just the chloroplast, and are thus found in most plant organs and tissues, albeit at trace levels in some tissues. In this review we summarise the current knowledge of the carotenoid content of non-green plastids and discuss what is known about the regulation of their biosynthesis in roots, fruits, flowers, tubers and seeds. The emphasis is on food crops as carotenoids are essential components of human diets, primarily as some are precursors of vitamin A. The low carotenoid content of many staple foods, such as cereals, can exacerbate dietary deficiencies. The World Health Organisation has estimated that more than 100 million children are vitamin A-deficient and up to 500,000 of these children become blind each year. Many of these children die within 12 months of going blind. Thus, understanding the regulation of carotenoid accumulation in food crops, especially tubers and cereals, should facilitate improvements to nutritional value with potentially significant health benefits.     

Dietary carotenoid levels affect carotenoid and retinoid allocation in female Chinook salmon Oncorhynchus tshawytscha

This study examined the effect of dietary carotenoid availability on carotenoid and retinoid concentrations in the flesh, plasma, skin and eggs of female Chinook salmon Oncorhynchus tshawytscha. Carotenoid concentrations in all tissues were closely related to dietary availability. Early in the breeding season, carotenoids were stored primarily in the muscle, with a flesh carotenoid concentration of 9·9 µg g^?1 in fish fed a high carotenoid diet compared with 1·9 µg g^?1 in fish fed a low carotenoid diet. During the breeding season, carotenoid reserves were mobilized predominantly to the eggs and also to the skin. By the end of the breeding season, carotenoid concentrations in the eggs were 17·9 µg g^?1 in fish fed a high carotenoid diet and 3·9 µg g^?1 in fish fed a low carotenoid diet. Conversely, egg retinoid concentrations were only c. 20% lower in fish fed a low v. high carotenoid diet, which suggests that retinoid concentrations were not limited by the availability of carotenoid precursors. Egg carotenoid concentrations were not correlated with either skin carotenoid concentration or colouration, which suggests that female carotenoid displays are not a reliable signal that males can use to evaluate egg carotenoid resources.     

Carotenoid biofortification in crop plants: citius,altius, fortius

Carotenoids are indispensable for human health, required as precursors of vitamin A and efficient antioxidants. However, these plant pigments that play a vital role in photosynthesis are represented at insufficient levels in edible parts of several crops, which creates a need for increasing their content or optimizing their composition through biofortification. In particular, vitamin A deficiency, a severe health problem affecting the lives of millions in developing countries, has triggered the development of a series of high-provitamin A crops, including Golden Rice as the best-known example. Further carotenoid-biofortified crops have been generated by using genetic engineering approaches or through classical breeding. In this review, we depict carotenoid metabolism in plants and provide an update on the development of carotenoid-biofortified plants and their potential to meet needs and expectations. Furthermore, we discuss the possibility of using natural variation for carotenoid biofortification and the potential of gene editing tools. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.     

Isolation and functional characterization of <Emphasis Type="Italic">Lycopene β-cyclase</Emphasis> (<Emphasis Type="Italic">CYC-B</Emphasis>) promoter from <Emphasis Type="Italic">Solanum habrochaites</Emphasis>

Background  

Carotenoids are a group of C40 isoprenoid molecules that play diverse biological and ecological roles in plants. Tomato is an important vegetable in human diet and provides the vitamin A precursor β-carotene. Genes encoding enzymes involved in carotenoid biosynthetic pathway have been cloned. However, regulation of genes involved in carotenoid biosynthetic pathway and accumulation of specific carotenoid in chromoplasts are not well understood. One of the approaches to understand regulation of carotenoid metabolism is to characterize the promoters of genes encoding proteins involved in carotenoid metabolism. Lycopene β-cyclase is one of the crucial enzymes in carotenoid biosynthesis pathway in plants. Its activity is required for synthesis of both α-and β-carotenes that are further converted into other carotenoids such as lutein, zeaxanthin, etc. This study describes the isolation and characterization of chromoplast-specific Lycopene β-cyclase (CYC-B) promoter from a green fruited S. habrochaites genotype EC520061.     

Validation of the effects of molecular marker polymorphisms in LcyE and CrtRB1 on provitamin A concentrations for 26 tropical maize populations

Vitamin A deficiency (VAD) compromises immune function and is the leading cause of preventable blindness in children in many developing countries. Biofortification, or breeding staple food crops that are rich in micronutrients, provides a sustainable way to fight VAD and other micronutrient malnutrition problems. Polymorphisms, with associated molecular markers, have recently been identified for two loci, LcyE (lycopene epsilon cyclase) and CrtRB1 (β-carotene hydroxylase 1) that govern critical steps in the carotenoid biosynthetic pathway in maize endosperm, thereby enabling the opportunity to integrate marker-assisted selection (MAS) into carotenoid breeding programs. We validated the effects of 3 polymorphisms (LcyE5′TE, LcyE3′Indel and CrtRB1-3′TE) in 26 diverse tropical genetic backgrounds. CrtRB1-3′TE had a two-ten fold effect on enhancing beta-carotene (BC) and total provitamin A (proA) content. Reduced-function, favorable polymorphisms within LcyE resulted in 0–30 % reduction in the ratio of alpha- to beta-branch carotenoids, and increase in proA content (sometimes statistically significant). CrtRB1-3′TE had large, significant effect on enhancing BC and total ProA content, irrespective of genetic constitution for LcyE5′TE. Genotypes with homozygous favorable CrtRB1-3′TE alleles had much less zeaxanthin and an average of 25 % less total carotenoid than other genotypes, suggesting that feedback inhibition may be reducing the total flux into the carotenoid pathway. Because this feedback inhibition was most pronounced in the homozygous favorable LcyE (reduced-function) genotypes, and because maximum total proA concentrations were achieved in genotypes with homozygous unfavorable or heterozygous LcyE, we recommend not selecting for both reduced-function genes in breeding programs. LcyE exhibited significant segregation distortion (SD) in all the eight, while CrtRB1 in five of eight digenic populations studied, with favorable alleles of both the genes frequently under-represented. MAS using markers reported herein can efficiently increase proA carotenoid concentration in maize.     

Biotechnological advancement in genetic improvement of broccoli (<Emphasis Type="Italic">Brassica oleracea</Emphasis> L. var. <Emphasis Type="Italic">italica</Emphasis>), an important vegetable crop

With the advent of molecular biotechnology, plant genetic engineering techniques have opened an avenue for the genetic improvement of important vegetable crops. Vegetable crop productivity and quality are seriously affected by various biotic and abiotic stresses which destabilize rural economies in many countries. Moreover, absence of proper post-harvest storage and processing facilities leads to qualitative and quantitative losses. In the past four decades, conventional breeding has significantly contributed to the improvement of vegetable yields, quality, post-harvest life, and resistance to biotic and abiotic stresses. However, there are many constraints in conventional breeding, which can only be overcome by advancements made in modern biology. Broccoli (Brassica oleracea L. var. italica) is an important vegetable crop, of the family Brassicaceae; however, various biotic and abiotic stresses cause enormous crop yield losses during the commercial cultivation of broccoli. Thus, genetic engineering can be used as a tool to add specific characteristics to existing cultivars. However, a pre-requisite for transferring genes into plants is the availability of efficient regeneration and transformation techniques. Recent advances in plant genetic engineering provide an opportunity to improve broccoli in many aspects. The goal of this review is to summarize genetic transformation studies on broccoli to draw the attention of researchers and scientists for its further genetic advancement.     

Carotenoid biosynthesis and biotechnological application

A survey is given on the carotenoid biosynthetic pathway leading to beta-carotene and its oxidation products in bacteria and plants. This includes the synthesis of prenyl pyrophosphates via the mevalonate or the 1-deoxyxylulose-5-phosphate pathways as well as the reaction sequences of carotenoid formation and interconversion together with the properties of the enzymes involved. Biotechnological application of this knowledge resulted in the development of heterologous carotenoid production systems using bacteria and fungi with metabolic engineered precursor supply and crop plants with manipulated carotenoid biosynthesis. The recent developments in engineering crops with increased carotenoid contents are covered.