Do Pollinators Contribute to Nutritional Health?

Despite suggestions that animal pollinators are crucial for human nutritional health, no studies have actually tested this claim. Here, we combined data on crop pollination requirements, food nutrient densities, and actual human diets to predict the effects of pollinator losses on the risk of nutrient deficiency. In four developing countries and across five nutrients, we found that 0 to 56% of populations would become newly at risk if pollinators were removed. Increases in risk were most pronounced for vitamin A in populations with moderate levels of total nutrient intake. Overall, the effects of pollinator decline varied widely among populations and nutrients. We conclude that the importance of pollinators to human nutrition depends critically on the composition of local diets, and cannot be reliably predicted from global commodity analyses. We identify conditions under which severe health effects of pollinator loss are most likely to occur.     

Nutritional enhancement of plants

Plants can provide most of the nutrients required in the human diet; however, the major staple crops are often deficient in some of these nutrients. Thus, malnutrition, with respect to micronutrients like vitamin A, iron and zinc, affects >40% of the world's population. Advances in molecular biology are being exploited to produce crops enhanced in these key nutrients. Other nutritional targets include the modification of fatty acid composition and the enhancement of antioxidant levels, particularly carotenoids, such as lycopene, and flavonoids. However, the benefit of these 'biofortified' crops to human nutrition remains to be elucidated.     

Long-term global trends in crop yield and production reveal no current pollination shortage but increasing pollinator dependency

There is evidence that pollinators are declining as a result of local and global environmental degradation [1-4]. Because a sizable proportion of the human diet depends directly or indirectly on animal pollination [5], the issue of how decreases in pollinator stocks could affect global crop production is of paramount importance [6-8]. Using the extensive FAO data set [9], we compared 45 year series (1961-2006) in yield, and total production and cultivated area of pollinator-dependent and nondependent crops [5]. We investigated temporal trends separately for the developed and developing world because differences in agricultural intensification, and socioeconomic and environmental conditions might affect yield and pollinators [10-13]. Since 1961, crop yield (Mt/ha) has increased consistently at average annual growth rates of approximately 1.5%. Temporal trends were similar between pollinator-dependent and nondependent crops in both the developed and developing world, thus not supporting the view that pollinator shortages are affecting crop yield at the global scale. We further report, however, that agriculture has become more pollinator dependent because of a disproportionate increase in the area cultivated with pollinator-dependent crops. If the trend toward favoring cultivation of pollinator-dependent crops continues, the need for the service provided by declining pollinators will greatly increase in the near future.     

Importance of pollinators in changing landscapes for world crops

The extent of our reliance on animal pollination for world crop production for human food has not previously been evaluated and the previous estimates for countries or continents have seldom used primary data. In this review, we expand the previous estimates using novel primary data from 200 countries and found that fruit, vegetable or seed production from 87 of the leading global food crops is dependent upon animal pollination, while 28 crops do not rely upon animal pollination. However, global production volumes give a contrasting perspective, since 60% of global production comes from crops that do not depend on animal pollination, 35% from crops that depend on pollinators, and 5% are unevaluated. Using all crops traded on the world market and setting aside crops that are solely passively self-pollinated, wind-pollinated or parthenocarpic, we then evaluated the level of dependence on animal-mediated pollination for crops that are directly consumed by humans. We found that pollinators are essential for 13 crops, production is highly pollinator dependent for 30, moderately for 27, slightly for 21, unimportant for 7, and is of unknown significance for the remaining 9. We further evaluated whether local and landscape-wide management for natural pollination services could help to sustain crop diversity and production. Case studies for nine crops on four continents revealed that agricultural intensification jeopardizes wild bee communities and their stabilizing effect on pollination services at the landscape scale.     

Global malnutrition overlaps with pollinator-dependent micronutrient production

Pollinators contribute around 10% of the economic value of crop production globally, but the contribution of these pollinators to human nutrition is potentially much higher. Crops vary in the degree to which they benefit from pollinators, and many of the most pollinator-dependent crops are also among the richest in micronutrients essential to human health. This study examines regional differences in the pollinator dependence of crop micronutrient content and reveals overlaps between this dependency and the severity of micronutrient deficiency in people around the world. As much as 50% of the production of plant-derived sources of vitamin A requires pollination throughout much of Southeast Asia, whereas other essential micronutrients such as iron and folate have lower dependencies, scattered throughout Africa, Asia and Central America. Micronutrient deficiencies are three times as likely to occur in areas of highest pollination dependence for vitamin A and iron, suggesting that disruptions in pollination could have serious implications for the accessibility of micronutrients for public health. These regions of high nutritional vulnerability are understudied in the pollination literature, and should be priority areas for research related to ecosystem services and human well-being.     

Current understanding of the regulation of methionine biosynthesis in plants

Plants can provide most of the nutrients for the human diet. However, the major crops are often deficient in some of the nutrients. Thus, malnutrition, with respect to micronutrients such as vitamin A, iron, and zinc, but also macronutrients such as the essential amino acids lysine and methionine, affects more than 40% of the world's population. Recent advances in molecular biology, but also the grasp of biochemical pathways, metabolic fluxes, and networks can now be exploited to produce crops enhanced in key nutrients to increase the nutritional value of plant-derived foods and feeds. Some of the predictions appear to be accurate, while others not, reflecting the fact that plant metabolism is more complex than presently understood. A good example for a complex regulation is the methionine biosynthetic pathway in plants. The nutritional importance of Met and cysteine has motivated extensive studies of their roles in plant molecular physiology, especially regarding to their transport, synthesis, and accumulation in plants. Recent studies have demonstrated that Met metabolism is regulated differently in various plant species.     

马铃薯维生素代谢研究应用进展

越来越多的人们逐渐意识到饮食与健康之间的紧密联系,粮食“量”与“质”协调发展的矛盾也开始凸显。马铃薯是全球第四大粮食作物,我国正在推进的“健康中国”建设和马铃薯主粮化战略给马铃薯育种和食品加工带来了更多的挑战和机遇。与其他粮食作物相比,马铃薯中维生素含量是最全面的,但市场上尚缺乏“量”与“质”俱佳的马铃薯品种和产品,因此这一领域存在着巨大的研究潜力。着重介绍了马铃薯维生素代谢研究的最新进展,探讨了在马铃薯营养代谢改良中的应用前景,以期为以健康为导向的营养强化研究做好技术储备,满足多样化的市场需求。     

How much does agriculture depend on pollinators? Lessons from long-term trends in crop production

Background and Aims

Productivity of many crops benefits from the presence of pollinating insects, so a decline in pollinator abundance should compromise global agricultural production. Motivated by the lack of accurate estimates of the size of this threat, we quantified the effect of total loss of pollinators on global agricultural production and crop production diversity. The change in pollinator dependency over 46 years was also evaluated, considering the developed and developing world separately.

Methods

Using the extensive FAO dataset, yearly data were compiled for 1961–2006 on production and cultivated area of 87 important crops, which we classified into five categories of pollinator dependency. Based on measures of the aggregate effect of differential pollinator dependence, the consequences of a complete loss of pollinators in terms of reductions in total agricultural production and diversity were calculated. An estimate was also made of the increase in total cultivated area that would be required to compensate for the decrease in production of every single crop in the absence of pollinators.

Key Results

The expected direct reduction in total agricultural production in the absence of animal pollination ranged from 3 to 8 %, with smaller impacts on agricultural production diversity. The percentage increase in cultivated area needed to compensate for these deficits was several times higher, particularly in the developing world, which comprises two-thirds of the land devoted to crop cultivation globally. Crops with lower yield growth tended to have undergone greater expansion in cultivated area. Agriculture has become more pollinator-dependent over time, and this trend is more pronounced in the developing than developed world.

Conclusions

We propose that pollination shortage will intensify demand for agricultural land, a trend that will be more pronounced in the developing world. This increasing pressure on supply of agricultural land could significantly contribute to global environmental change.Key words: Agricultural production, biotic pollination, crop diversity, cultivated area, developed world, developing world, FAO, randomization     

Contribution of insect pollination to nutritional security of minerals and vitamins in Korea

Crop production for human food and nutritional security is largely dependent on pollination process especially by insects. We assessed the role of pollination in connection with micronutrient supply from edible crops to the Korean population. The study included 42 predominant crop types of varying pollinator dependence. A higher pollinator dependency than present global average was noted in connection with all minerals deemed nutritionally important and vitamins. Pollinator-dependent (PD) crops provide a substantial share of micronutrients to the population, especially with regard to vitamins C and E and elements iron. A positive trend was found in the PD supply of all micronutrients over the last 30?years in Korea, but the rate of increment was somewhat lower for vitamins C and K as well as folate. The results demonstrated the importance of pollination for human nutritional security and conservation of insect pollination system for the sustained ecosystem service.     

Plant ionomics: a newer approach to study mineral transport and its regulation

Up to two-thirds of the world population is at risk of deficiency in one or more essential mineral elements. In order to overcome deficiency disorders of mineral nutrients, biofortification approach in crops is an absolute requirement to eliminate the hidden hunger. Hence, the aim of crop biofortification is shifting from food security to nutritional security. In this context, ionomics becomes essential to identify potential gene(s) responsible for the uptake, transport, and storage of ions in plants. It involves the measurement of elemental composition of an organism and change in their composition in relation to physiological, developmental, environmental, and genetic factors. It renders the functional analysis of genes and gene networks that directly or indirectly affect the whole ionome. The present review deals with the study of ionome with special reference to different types of ionic interactions, quantifications, and gene identification.     

Effect on lycopene, β-carotene,ascorbic acid and phenolic content in tomato fruits infected by Alternaria alternata and its toxins (TeA,AOH and AME)

Tomato is considered as one of the most important sources of nutrients such as lycopene, β-carotene, flavonoids, ascorbic acid (vitamin C) and hydroxyl-cinnamic acid derivatives. The quality and quantity of nutrients in tomato fruits were decreased during the severe infection of Alternaria alternata. The present study deals with the estimation of lycopene, β-carotene, phenolic and ascorbic acid content in tomato fruits which were infected with A. alternata and its toxins such as tenuazonic acid (TeA), alternariol (AOH) and alternariol monomethyl ether (AME). The lycopene, β-carotene, ascorbic acid and phenolic content were found lowest in pathogen-infected fruits i.e. (0.66 ± 0.03 mg/g), (0.14 ± 0.01 mg/g), (1.89 ± 0.2 mg/g) and (0.58 ± 0.05 mg/g), respectively, followed by toxins-treated samples as compared to the control. The results concluded that A. alternata mostly affects the nutritional values of tomato fruits due to the combined effect of the toxins.     

Global agricultural productivity is threatened by increasing pollinator dependence without a parallel increase in crop diversification

The global increase in the proportion of land cultivated with pollinator‐dependent crops implies increased reliance on pollination services. Yet agricultural practices themselves can profoundly affect pollinator supply and pollination. Extensive monocultures are associated with a limited pollinator supply and reduced pollination, whereas agricultural diversification can enhance both. Therefore, areas where agricultural diversity has increased, or at least been maintained, may better sustain high and more stable productivity of pollinator‐dependent crops. Given that >80% of all crops depend, to varying extents, on insect pollination, a global increase in agricultural pollinator dependence over recent decades might have led to a concomitant increase in agricultural diversification. We evaluated whether an increase in the area of pollinator‐dependent crops has indeed been associated with an increase in agricultural diversity, measured here as crop diversity, at the global, regional, and country scales for the period 1961–2016. Globally, results show a relatively weak and decelerating rise in agricultural diversity over time that was largely decoupled from the strong and continually increasing trend in agricultural dependency on pollinators. At regional and country levels, there was no consistent relationship between temporal changes in pollinator dependence and crop diversification. Instead, our results show heterogeneous responses in which increasing pollinator dependence for some countries and regions has been associated with either an increase or a decrease in agricultural diversity. Particularly worrisome is a rapid expansion of pollinator‐dependent oilseed crops in several countries of the Americas and Asia that has resulted in a decrease in agricultural diversity. In these regions, reliance on pollinators is increasing, yet agricultural practices that undermine pollination services are expanding. Our analysis has thereby identified world regions of particular concern where environmentally damaging practices associated with large‐scale, industrial agriculture threaten key ecosystem services that underlie productivity, in addition to other benefits provided by biodiversity.     

Thermal time – concepts and utility

Wheat was among the last of the major crops to be transformed (in 1992), and transformation is still difficult, with a lower efficiency than that for maize and rice. However, the recent development of Agrobacterium‐based systems is set to improve the precision of the process, while new methods of selection, removal of unnecessary DNA sequences, gene targeting and in vivo mutagenesis will make the process cleaner and more acceptable to regulatory authorities and consumers. Our current work is focussed on using transformation to understand and manipulate aspects of grain processing quality, notably dough strength and texture for milling. However, it is clear that a major priority for future work will be to improve nutritional quality, including vitamin and mineral contents for the developing world and starch digestibility and dietary fibre content and composition for developed countries.     

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.     

Species Distribution Models for Crop Pollination: A Modelling Framework Applied to Great Britain

Insect pollination benefits over three quarters of the world''s major crops. There is growing concern that observed declines in pollinators may impact on production and revenues from animal pollinated crops. Knowing the distribution of pollinators is therefore crucial for estimating their availability to pollinate crops; however, in general, we have an incomplete knowledge of where these pollinators occur. We propose a method to predict geographical patterns of pollination service to crops, novel in two elements: the use of pollinator records rather than expert knowledge to predict pollinator occurrence, and the inclusion of the managed pollinator supply. We integrated a maximum entropy species distribution model (SDM) with an existing pollination service model (PSM) to derive the availability of pollinators for crop pollination. We used nation-wide records of wild and managed pollinators (honey bees) as well as agricultural data from Great Britain. We first calibrated the SDM on a representative sample of bee and hoverfly crop pollinator species, evaluating the effects of different settings on model performance and on its capacity to identify the most important predictors. The importance of the different predictors was better resolved by SDM derived from simpler functions, with consistent results for bees and hoverflies. We then used the species distributions from the calibrated model to predict pollination service of wild and managed pollinators, using field beans as a test case. The PSM allowed us to spatially characterize the contribution of wild and managed pollinators and also identify areas potentially vulnerable to low pollination service provision, which can help direct local scale interventions. This approach can be extended to investigate geographical mismatches between crop pollination demand and the availability of pollinators, resulting from environmental change or policy scenarios.     

Maternal-fetal transfer and metabolism of vitamin A and its precursor β-carotene in the developing tissues

The requirement of the developing mammalian embryo for retinoic acid is well established. Retinoic acid, the active form of vitamin A, can be generated from retinol and retinyl ester obtained from food of animal origin, and from carotenoids, mainly β-carotene, from vegetables and fruits. The mammalian embryo relies on retinol, retinyl ester and β-carotene circulating in the maternal bloodstream for its supply of vitamin A. The maternal-fetal transfer of retinoids and carotenoids, as well as the metabolism of these compounds in the developing tissues are still poorly understood. The existing knowledge in this field has been summarized in this review in reference to our basic understanding of the transport and metabolism of retinoids and carotenoids in adult tissues. The need for future research on the metabolism of these essential lipophilic nutrients during development is highlighted. This article is part of a Special Issue entitled: Retinoid and Lipid Metabolism.     

Seasonal complementary in pollinators of soft-fruit crops

Understanding the relative contributions of wild and managed pollinators, and the functional contributions made by a diverse pollinator community, is essential to the maintenance of yields in the 75% of our crops that benefit from insect pollination. We describe a field study and pollinator exclusion experiments conducted on two soft-fruit crops in a system with both wild and managed pollinators. We test whether fruit quality and quantity is limited by pollination, and whether different pollinating insects respond differently to varying weather conditions. Both strawberries and raspberries produced fewer marketable fruits when insects were excluded, demonstrating dependence on insect pollinators. Raspberries had a short flowering season which coincided with peak abundance of bees, and attracted many bees per flower. In contrast, strawberries had a much longer flowering season and appeared to be much less attractive to pollinators, so that ensuring adequate pollination is likely to be more challenging. The proportion of high-quality strawberries was positively related to pollinator abundance, suggesting that yield was limited by inadequate pollination on some farms. The relative abundance of different pollinator taxa visiting strawberries changed markedly through the season, demonstrating seasonal complementarity. Insect visitors responded differently to changing weather conditions suggesting that diversity can reduce the risk of pollination service shortfalls. For example, flies visited the crop flowers in poor weather and at the end of the flowering season when other pollinators were scarce, and so may provide a unique functional contribution. Understanding how differences between pollinator groups can enhance pollination services to crops strengthens the case for multiple species management. We provide evidence for the link between increased diversity and function in real crop systems, highlighting the risks of replacing all pollinators with managed alternatives.     

Role of carotenoids and retinoids during heart development

The nutritional requirements of the developing embryo are complex. In the case of dietary vitamin A (retinol, retinyl esters and provitamin A carotenoids), maternal derived nutrients serve as precursors to signaling molecules such as retinoic acid, which is required for embryonic patterning and organogenesis. Despite variations in the composition and levels of maternal vitamin A, embryonic tissues need to generate a precise amount of retinoic acid to avoid congenital malformations. Here, we summarize recent findings regarding the role and metabolism of vitamin A during heart development and we survey the association of genes known to affect retinoid metabolism or signaling with various inherited disorders. A better understanding of the roles of vitamin A in the heart and of the factors that affect retinoid metabolism and signaling can help design strategies to meet nutritional needs and to prevent birth defects and disorders associated with altered retinoid metabolism.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.     

A dynamic nonlinear optimization study of Mountain Pima subsistence technology

A dynamic nonlinear optimization analysis of subsistence patterns of the Mountain Pima of Chihuahua, Mexico, included requirements for adequate amounts of calories, calcium, vitamin A, vitamin C, and balanced protein. Two methods of incorporating nonenergy nutritional needs into a time minimization program were compared. The first was a constraint model with sharp boundaries between adequacy and fatality. The second involved multiplying the total work time by a series of nutrient indexing factors. Each factor was calculated as a function of the ratio between the recommended and actual rates of intake for all months and nutrients considered. Oxalate composition of some resources and seasonal variation in resource availability were taken into account. Two sets of data were analyzed, one for a year of adequate rainfall, the other for a year of severe drought. The predictions of the indexing model agreed more closely with observed intake patterns than did the predictions of the constraint model.     

Nutrition of the Fetus and Newborn

Both the successful development of healthy, long-term animal models to study fetal nutrition and metabolism and the improved survival of low-birth-weight, preterm infants have focused interest and research on fetal and neonatal nutrition and metabolism. Such a focus is important, given the recent emphasis on promoting neonatal growth in preterm infants at “normal” in utero growth rates. Estimates of nutrient requirements for growth in a human fetus remain ill defined, however. Body composition data appear biased toward thin infants. Animal data suggest that fetal nutrition proceeds according to species-specific growth rates, with variations in fat content largely dependent on placental fat permeability and on maternal nutrient supply as regulated by the placenta.After birth, neonatal nutrition is affected primarily by food intake and the functional integrity and capacity of the gastrointestinal tract. Additionally, muscle activity, thermoregulation and stresses of various kinds and degrees modify a neonate''s nutritional requirements. Functional deficits of the gastrointestinal tract have been circumvented by a more aggressive use of intravenous nutrition. Both intravenous and enteral nutrient mixtures have been substantially improved in the quantity of all nutrients and have been modified qualitatively toward compositions that are closer to those of human milk. These nutrient mixtures now produce plasma nutrient concentrations that approximate those of a healthy, breast-fed infant.Although such efforts to improve the nutritional balance and growth of preterm infants have been successful, much remains to be learned about the nutritional requirements of sick infants.