What makes golden rice golden

There were no severe lodging incidences observed. Generally, crop stand was good with manageable level of insect pests and diseases during the growing seasons. Insects observed both pest and beneficial insects were found to be present in both test materials.

We did not notice any difference between GR2E introgression lines and their respective recipient parents for the pest or diseases pressure on the crop across the confined field tests. Woodfield and White 23 , and Badenhorst et al. For commercial deployment of any new variety with one or more introduced new trait s of a staple crop, in parallel to yield and other key agronomic traits, the newly developed variety should have essentially similar or better performance against biotic and abiotic stresses and grain quality traits compared to recipient variety; the introduced trait s should not alter these traits of the recipient variety 25 , Furthermore, different cooking and eating quality traits like, AC and ASV did not show any significant difference between the ILs and their respective recipient parents in any CTs.

The golden rice breeding lines with significant amount of provitamin A accumulated in the grains helps to tackle VAD in high risk countries such as Bangladesh and the Philippines. However, it is a requirement to assess the composition of genetically modified crops to see if any significant changes in grain quality, nutrients and anti-nutrients contents in comparison to traditional counterpart and to assess the safety of the intended or unintended changes 27 , The compositional analysis of golden rice showed that all the compounds measured are within the biologically acceptable range and does not pose any risk to human health Earlier reports on transgenic products for insect and herbicide tolerance have also shown that little biologically meaningful changes in grain quality, nutrient and anti-nutrient composition There was a clear environmental effect, even though total carotenoids varied with environments, the genotypes with high carotenoids were always the best in all the locations.

Such variations in trait expression due to environmental and agronomic factors and genetic basis have been well explained 31 , Total carotenoids were well correlated across the sites and generations; and expressed stably across the environments but there is a genetic background effect. Carotenoids expression varied even within segregating lines of different generations in each of the genetic backgrounds.

So targeted breeding and careful selection of progenies with carotenoids test in each generation is necessary for advancing the lines. The highest expression of carotenoids was observed in BR29 background and the lowest in IR64 background. Several earlier attempts to develop golden rice events and introgression lines had to face the genetic background effects. Moreover, ILs did not show any significant difference in yield when expressing the genes in the carotenoid pathway In our study also lowest expression was noticed in IR Simultaneously efforts are being made to develop next generation golden rice events with elevated levels of carotenoids with longer stability 37 , 38 , However, a genetic background effect is still a major bottle neck for introgression of carotenoid trait.

Background effect on the expression of introduced traits was reported in rice for submergence tolerance, yield and related traits, disease resistance and drought tolerance 15 , 16 , 40 , The variation in carotenoid concentration in grains might be due to variations in sunlight exposure and intensity across the locations and seasons Moreover, like other carotenoids containing crops the carotenoid concentration in the grains of golden rice degrades over time after harvest.

The degradation rate is very high at first few weeks after harvest and it becomes very slow after 6—8 weeks data not shown. The carotenoids degradation rate is highly influenced by the storage temperature, moisture and exposure to light of the storage environment 22 , So, development of golden rice varieties with stable carotenoids expression is essential to achieve the impact However, there might be genotypic effect on the retention ability for carotenoids in rice grain.

Understanding background effect and standardization of post-harvest handling is needed to achieve desired level of carotenoids in the introgression lines of multiple backgrounds. The five back crosses of GR2E gene into three genetic backgrounds resulted in identification of ILs similar to respective recipient parents. Adoption by the farmers and preference by the consumers for a specific crop variety particularly rice introduced with a new trait largely depends on its yield, grain quality and eating quality parameters.

The introduced trait should be stable over locations and seasons to expedite the adoption level. Kaybonnet is a high yielding japonica rice variety with blast resistance and excellent milling quality commercially cultivated in the USA. Erwinia uredovora. In each generation, segregating materials were genotyped using GR2E event specific molecular marker.

Plants containing the GR2E event and phenotypically similar to respective recipients were selected and backcrossed in each backcross generation to advance the materials to BC 5 F 2. Only yellow-colored BC 5 F 2 seeds were separated and analyzed for total carotenoid content. We have provided details of MAB scheme and evaluation of introgression lines in the Fig.

Plants were genotyped using GR2E specific markers and homozygous plants were selected. Seeds of the selected plants of GR2E introgression lines, recipient and donor parents were seeded in trays. Details of the experimental design and layout are provided in Tables S1 and S2.

Standard agronomic practices were followed to raise a good crop, including the application of need-based plant protection measures to protect the crop from diseases and insect pests.

Data were gathered on key agronomic, yield and yield-related traits; and total carotenoid content was measured two months after harvest. Agronomic traits were measured on five random plants from each entry. At maturity, five selected plants were harvested from individual plots and the remaining inner plants were harvested in bulk. Nanopore was used to check the quality and quantity of the DNA extracted. Amplification products were separated by gel electrophoresis on 1.

The GR2E specific primer sequences as follows. Amylose content AC was determined on milled rice extracts using a segmented flow analyzer. Rice samples were ground to a fine powder using a cyclone mill. Sodium Hydroxide and Ethanol were added to a test portion of the sample and heated in a boiling bath for 10 min.

Acetic acid and Iodine solution was mixed with the aliquot of the test solution to form a blue starch iodine complex and its absorbance was measured at nm using a colorimeter The result of the analysis was reported as apparent amylose to take into account the contribution of amylopectin present in the rice, which also forms a blue color starch iodine complex. Rice starch gelatinization temperature GT was estimated by determining the alkali spreading value ASV of milled rice grains in potassium hydroxide solution.

Six kernels of whole milled rice were incubated with 10 ml of 1. The appearance and disintegration of the endosperm was visually rated depending on the intensity of spreading and swelling. Samples of milled rice were ground to a fine powder, placed in a culture tube and suspended in a mixture of ethanol and 0. Gel consistency of the rice paste 4. Rice was differentiated into three consistency types—soft 61 to mm , medium 41 to 60 mm and hard 27 to 40 mm.

Total carotenoid concentration was estimated following the protocol developed by Gemmecker et al. Dehulled and polished rice seeds were ground to a fine powder using a modified paint shaker and accurately weighed amounts ca.

Cooled samples were centrifuged g , 5 min and the supernatant fractions were transferred to new ml tubes. Supernatants were transferred to ml tubes and the pellets were re-extracted twice more with 2-ml volumes of acetone and the resulting supernatant fractions were combined. After vortexing, phase separation was achieved by centrifugation g , 5 min. The combined organic phases were dried using a vacuum-concentrator Eppendorf concentrator and re-dissolved in 1 ml acetone.

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Keywords: golden rice, vitamin A deficiency, substantial equivalence, proteomics, metabolomics. The use, distribution or reproduction in other forums is permitted, provided the original author s or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice.

No use, distribution or reproduction is permitted which does not comply with these terms. This article is part of the Research Topic Nutrient sensing, signaling and transport in plants View all 12 Articles. Sarkar 1 , Swapan K. Introduction Carotenoids not only have a high nutritional value but also play a pivotal role in physiological functions such as vision, growth, reproduction, cellular differentiation, proliferation, and immunity Tang et al.

Materials and Methods Rice Sample In our previous study, transgenic golden rice was developed by manipulation of phytoene synthase psy and phytoene desaturase crtI gene in the genome of two popular Asian rice cultivars, IR64 and BR29 Datta et al. But for now, let us concentrate on achieving adoption of the first nationally approved Golden Rice variety in your country.

It will be clear by now that Golden Rice adoption in a country requires the engagement of several functions of Government, many of whom may not be used to working together. These include agriculture, health, nutrition, medical, women and child welfare, communications, budget and strategic planning. There may be others, including subgroupings within the main functions.

Additionally, there are Government rice seed multiplication and distribution systems. In some countries, these functions are performed solely by Government-funded units, in others the Government contracts with the private sector to provide part or all of the required service.

Cooperation in planning and running public meetings may be appropriate, for example, between agricultural extension services, and local government health and nutritional education specialists, with all specialists benefiting by working with communications specialists. There are also roles for different levels of government: village, region, city and national. It would be extremely helpful, in each country and at each level of government and in each necessary function, for interested individuals to announce their interest, reach out to other functions and individuals in the same and the other functions, at the same level of government, whom they may not previously know, and bring people together to discuss how to coordinate their activities for the common purpose: improved health and welfare through Golden Rice adoption.

It would be useful for each appropriate level of government, for the relevant group to elect a leader through discussion. And then to invite participation from all other functions needed for efficient and timely decision-making and management of resources needed or controlled by the group to facilitate adoption of Golden Rice.

The relevant leaders from each level of government then need to establish linkages with the corresponding leaders of groups in the other levels of government. From these responsible self-help initiatives, a national coordinating system should develop to allocate, prioritise and direct the use of relevant resources to improved health and welfare through Golden Rice adoption. In theory, one seed grain of rice can result in 20, tonnes of rice in a few years if all the seed produced is replanted after harvesting each crop cycle.

Rice has a tremendous capacity for multiplication. But practically, Golden Rice seed cannot be made available to all farmers in a country at the same time.

Seed multiplication output and dissemination have to be prioritised. Conversely, Golden Rice communication and support services to growers and consumers may be the most difficult to manage in very remote areas. The Golden Rice seed multiplication and distribution system will be able to advise on what production can be expected in what time scale. It will be necessary to integrate need with practicality in determining which areas in a country should be the first recipients of Golden Rice seed for farmers to grow.

Locally discussed and informed decisions will be the best way to decide on priorities. The Golden Rice nutritional trait has been introduced into locally adapted and preferred rice varieties and such work will continue. These Golden Rice varieties grow the same as the equivalent white rice variety. Before farmers will grow Golden Rice, they will need to know that they will be able to sell it and that their profitability will not be adversely affected compared to growing white rice.

The rice breeders need to communicate these facts to local growers. Other communication methods may be required, all of course in local language. For consumers to want to buy and consume Golden Rice, they will need initial encouragement.

They need to be reassured that there can be no adverse effects of consuming Golden Rice as a source of vitamin A, which is essential for maintenance of healthy sight and a healthy immune system to combat disease. They need to understand that the only possible effect of consumption is beneficial and that independent local scientists as well as foreign scientists and clinicians have reviewed all the relevant data and found Golden Rice to be safe to humans and the environment.

They need to understand that each Golden Rice grain is uniformly labelled with its colour, which is different from spoiled rice and rice which fraudsters may have coloured in imitation of Golden Rice. This uniform colour of Golden Rice, which shows that it contains beta-carotene, is the only difference from the same white rice variety. The taste is the same as the white rice variety, and of course consumers will need to become used to eating it regularly, for it to be effective.

It is necessary to understand how to reach consumers, and tailor the approach to local circumstance, for effective communication. In some places, it may be via radio, it could be via text message, or TV, or newspapers or other social media. Who do consumers trust? Perhaps it is the local health workers? Perhaps a popular health programme, perhaps celebrity sports, film or TV personalities?

Focus groups probably need to be run to establish which would be the most effective, and the most cost-effective, communication messages and channels.

Maybe the local business school can provide training in how to organise these, and record the results to influence strategy. When systems have been tried, results should be measured, and learning applied to future iterations of the systems so that they become more and more efficient at message delivery. The aim is, at a low per capita cost, to establish demand for Golden Rice from consumers as encouragement to farmers to grow and harvest it.

After such demand has been created, after a few cycles it will then continue without continuous social marketing. Of course, grower interest and consumer demand have to be developed together, which is more challenging than introducing a new rice variety which only benefits the grower.

For initial crops of Golden Rice, perhaps Government, local or central, needs to guarantee to purchase the crop, to start the cycle of availability and consumption. Whereas in rural setting this will probably not be needed for many crop cycles, there are other settings where government purchase and distribution programmes for Golden Rice may usefully continue. Vitamin A deficiency occurs not only in the countryside, but also in urban centres where the population has no opportunity to grow their own Golden Rice: for these locations, an ongoing Government-managed supply system will probably be beneficial.

In some countries, there is a well-established midday meal service in schools. Mandatory inclusion, and supply of Golden Rice as part of the midday meal would do a lot to combat vitamin A deficiency in the most vulnerable group to vitamin A deficiency: children.

Where such a service does not currently exist, perhaps it could be created and Golden Rice routinely served. Alternatively, perhaps each child could be provided with a bag of polished Golden Rice to take home for preparation and consumption, on a regular basis, and receive instruction on the expected benefits in school to share with parents.

Again, local experience and commitment will determine the most appropriate way forward. And again, measurement of progress from the first beginning, for example, of the different delivery systems for the nutritional message will allow refinement and improvement in processes to make them more and more effective in the later targeted adoption areas. The same measurement systems will also allow determination of when external support can be reduced without adverse impact, so that available resources can be focussed elsewhere.

It is well established that a source of vitamin A is beneficial to health, with no side effects. The human body converts the coloured beta-carotene in Golden Rice to vitamin A.

Beta-carotene surplus to the bodies requirement is excreted without conversion to vitamin A. Mothers have sufficient vitamin A when the circulating vitamin in their blood protects the mothers sight and ensures a robust immune response to infections. It is important to measure the effectiveness of Golden Rice adoption.

Initially, this will need to be by proxy measurements. Dietary records are useful.