Description
🐝WHY ARE BEES SO IMPORTANT?
Despite being small creatures, bees are extremely important for the environment and humanity. There are over 20.000 bee species around the world, from social to solitary bees, sting bees to stingless bees. In Brazil only, there are about 3.000 bee species, the greatest diversity of bees in the whole world [1]! All of them serve many ecosystem services, including a very important one: plant pollination.
Ecological importance
When bees are visiting a plant to collect its pollen and nectar, pollen grains from the anthers get stuck to its body so when they next come in contact with the stigma (from the same flower or other flowers from the same species), fecundation happens [2]. So, by pollinating plants, they guarantee the species reproduction as well as genetic variability. Because of that, 85% of species that compose forests are dependent on this service from different types of bees, the most known being the western honey bee (Apis mellifera) the most frequent floral visitor [3, 4,11].
Bees are the main pollinators, responsible for the preservation of many plant species worldwide. In Brazil, a single group of bees (the stingless Meliponina) already contributes to the pollination of 40% to 90% of all tree species, maintaining the country's native forest and the ecosystems biodiversity [2,3].
Breaking the ecosystem stability, by disturbing ecological relationships maintaned by animals and plants influenced by pollination, can cause a great domino effect, resulting in the disturbance of the environment, as well as compromise the oxygen disponibility and water resources by the vegetation decrease [1, 12].
Economic importance
Among the plants they are responsible for pollinating, there are many crops important for economy. About 70% of the plants that are cultivated for human consumption benefit from bee pollination, whether in quality or quantity of the product [5]. When looking into the brazillian scenario only, bees contribute to almost 80% of crops! Some of them are even totally dependent on bees: without them, some foods just would not be produced anymore or would turn into luxury items. [6]
REFAZER GRÁFICOS OU PEGAR PARECIDOS (PQ TÃO EM INGLÊS E TBM VAI QUE DÁ COPYRIGHT KKK)
IMAGEM COM ALGUNS ALIMENTOS QUE SÃO POLINIZADOS POR ABELHAS (café, amêndoa, maçã, blueberry, morango, tomate ...), mostrando como a diversidade da nossa comida poderia cair blabla que nem a gnt fez nos slides de várias apresentações
Pollination by bees is required for a healthy increase in agricultural productivity, generating a higher amount, as well as fruits with better quality and with more seeds [2]. Fruits that do not get pollinated receive less resources from the plant, creating deformities that cause farmers to throw them away instead of selling them [12].
Bees' importance is manifested into a third of all the food we eat, as well as other products that depend on agriculture, like the fibers for our clothes, biofuel and vegetable oil, and, of course, their honey [12]. Without them, our meals would be much bare and joyless.
Because of the reliance of farmers production on them, alone they represent 10% of all the agricultural GDP, 100 billion USD per year [1]. This value can also represent the direct loss in economy if they were to disappear completely.
By ignoring the problem of their disappearance, we not only can expect a future environmental collapse, but also a economic catastrophe, with less and worse food and a decrease in countries' GDP and employment offer.
🌎WHY ARE BEES DISAPPEARING?
Although it is common to call the scenario "bees' disappearance", the bees are not actually disappearing, they are mostly dying in masses. The fact has been noticed since the 1990s and has caused about 25% of known bee species to be reported missing to this day [7].
(GRÁFICO DE DECLÍNIO DE ABELHAS)
Many are the causes for the phenomenon, for instance migration stress, drought, diseases, climate change and, especially, pesticides are some of the interferences [7]. Depending on the type of situation it can be attributed to different occurences, the most important ones being: extinction by habitat loss, Colony Collapse Disorder (CCD) and acute intoxication.
A very important factor associated with the loss of biodiversity is the changes in land use, which has resulted in habitat loss. A crucial example is the evergrowing advance of urban areas towards native forests [5], a reflection of the search for productivity in agricultural activities, that results in malnutrition by low forage availability[14].
Overall, CCD and acute intoxication have been receiving a lot of attention because of their meaningful participation and their relation to the misuse of pesticides, especially the neonicotinoid class [13].
Specifically for social managed bee species like Apis mellifera, the phenomenon has been called Colony Collapse Disorder (CCD), which, among multifactorial causes that are still under study, has been highly attributed to the use of pesticides. It has been reported especially in the United States, where at least 30% of colonies were lost by successive deaths between 2006 and 2010, and in some countries of Europe. In CCD, some symptons are observed: rapid loss of worker bees, increase in the ratio of offsprings to adults, absense of offsprings, dead adult bees and avoidance of hive invasion by pests [5]. The interaction of pesticides have been proposed to potentialize the symptons of pathogenic agents, contributing to the syndrome by making the colony more vulnerable [17].
Yet, in Brazil and many other countries, although there are studies over possible cases of CCD none of them are corroborated. Brazilian bees' deaths are very associated to acute intoxication by pesticides, usually in lethal concentrations. Despite that, sublethal concentrations of pesticide directly affects one bee individual, evidence shows that this detrimental effect cascades over to the whole colony.
The overall loss of resource diversity associated with landscape simplification, in combination with the debilitating effect of pesticides of bee species has facilitated for disease to be more common within the colony [5]. Brazil is recognized as a great pesticide consumer worldwide [5] and, as we can see, those substances are main actors in the disappearance of bees and, accordingly, in the unbalance of environment and economy. About three quarters of all honey contains traces of those toxic compounds [16]. A specific class of pesticides has been highly associated with the situation: the neonicotinoid class.
THE PESTICIDE: IMIDACLOPRID
The neonicotinoids are the most widely used class of pesticides in the whole world, even after being restricted in the European Union [17]. They are neurotoxins very selective to insects over vertebrates, competitively targeting their nicotinic acetylcholine receptor (nAChR) in neurons, as agonists. The most used one is the Imidacloprid, due to its high efficacy and systemic activity in plants, its residues are the most found in fruits and vegetables in Brazil [15, 18]. Ever since the beginning of the reports of the bees' disappearance, Imidacloprid has been highly associated to the situation.
Figure X. Imidacloprid structure.
It is usually applied to the seed, spreading through the plant's system as it grows and, in this process, reaches the flowers, too [19]. Because of pollination, bees come in contact with the toxic substance by that structure, through pollen and nectar, by ingesting or touching it. Nectar provide them with carbohydrates, serving as an energy source, and the pollen is a crucial source of proteins and fats. For that reason, bees take the pollen and nectar they collect back to their hive to be stored, processed and consumed by other bees [20]. Thus, if the nectar and pollen is contaminated by the pesticide, it can affect not only the bee that collected it, but its entire hive!
When Imidacloprid enters the bee's system, it can turn into metabolites that can be even more toxic, like olefin [21]. Depending on its concentration, it can have different (but equally bad) effects on the bees. In a high enough concentration, it can kill the bee (acute intoxication). But even in sublethal concentrations, which is more common to find, imidacloprid can cause chronic toxicity, harming them physiologically or behaviorally. It has an impact on their motor and cognitive functions, such as learning, flying, feeding and navigation memory abilities. This way, it also impairs their foraging and, finally, their survival, in a way that they often die far away from their own colony [22, 13].
However, some overexpressed enzymes from the CYP P450 superfamily have been described as participants in the neonicotinoid resistance of some insects, converting imidacloprid into less harmful metabolites [15]. Those enzymes are very important for the development of our project.
But, before we tell you about our project, there is something we can not ignore about
neonicotinoids
Even though they are marked as contributors to the bee disappearance phenomenon, neonicotinoids are very effective pesticides for pest control, surpassing many others. Banning or impairing their function can have a negative effect on crops' production and create the need to apply a higher amount of other pesticides, a solution that can be even more harmful to the environment and also cost more money [23]. In short, neonicotinoids are very necessary for agriculture.
Therefore, our solution, Let.it.bee., tries to address the issue without cancelling the important pest control effect.
WHAT IS LET.IT.BEE.?
Our inspiration
Because of bees' great importance to the planet and consequent consonance with multiple United Nations' Sustainable Development Goals (SDGs), our team was inspired to adopt the cause and help save them.
In 2018 and 2019, about half a billion bees were found dead in different regions of Brazil, the main cause was attributed to their contact with pesticides, especially neonicotinoids [8]. This occasion brought a lot of attention to the worries surrounding the disappearance of these insects.
But, despite that event, in the beginning of 2020, our team found out that the Brazil's government had just released the use of 493 pesticides, the highest number of substances approved in all of the country's history. It is only a part of an upward trajectory of pesticide approval that is happening ever since 2016 [9]. Among them, there are even pesticides that are prohibited in other countries, such as Fipronil that was banned in part of the European Union, because of their effects in human health or involvement in the death of bees [10].
Agriculture is a very important sector for Brazil, along with livestock. The business is responsible for more than 20% of the country's Gross Domestic Product, corresponding to almost half of all the exportation, too [24,25 ]. For soy, sugar cane, orange juice and coffee, for example, Brazil is both the best producer and exporter on the world, while some of this products are totally dependent on bee pollination [25]. Consequently, knowing about the relationship of bees with crops' productivity, the problem should be receiving more consideration.
Thus, by hearing and learning more about the death of their populations around the world, and especially in our country, as well as the terrible implications of the phenomenon, we decided to dive more into the problem and come up with a solution for a more sustainable agriculture: our project Let.it.bee.
Because of the pandemic and plant growth time, we have been working on this project since 2020, making it a two year project.
OUR GOALS
By reaching that goal, we can have a positive impact in both economy and environment, especially by contributing to:
- A sustainable and productive agriculture, by helping farmers keep their production protected against pests without harming the pollinators, while the productivity (in quantity and quality) of their crop grows with more bees to pollinate the plants. This can optimize production, as well as pesticide use and the land use.
- An economic growth, by stimulating farmers production and generating jobs in rural areas.
- The maintenance of the ecological balance, by keeping plants pollinated, thus maintaining the ecosystem functions, as well as its beauty. Besides heliping the plants that are pollinated by bees, it can also help the organisms that use them as home or as food, as well as the organisms that feed on those other organisms, and so on, maintaining the food chain and other ecological relationships.
- Food production, by improving quality and quantity of crops productions, offering more and better options for people.
- Lessen food waste, by producing fruits with better quality, with less deformities, that will not be thrown away by farmers.
HOW IT WORKS
To achieve our goals, we designed an adaptable genetic circuit system for plants, so the plant can express a detoxifying enzyme (CYP6G1), capable of metabolizing the pesticide Imidacloprid into less toxic metabolites, only in tissues that bees come in contact with the most during pollination, such as the pollen.
By doing this, the pollen of the plant that expresses the Let.it.bee. circuit will be safe for bees contact and consumption while the rest of the plant is still toxic to pests, making it a safe option for farmers to apply in their crops without losing the function of the pesticide.
Figure TANANA. General scheme of Let.it.bee.: a plant that does not express the circuit and thus has the pesticide toxicity in all tissues (up), while a plant that has the circuit inserted will express the enzyme locally and protect the pollinating bee (down).
Our test circuit was expressed in a micro-tomato plant and it contains:
- A specific pollen promoter
- A detoxifying enzyme
- A self-cleaving peptide
- The GUS reporter gene
You can check more about our project's genetic circuit and chassis in our Design page!
WHAT'S NEXT FOR LET.IT.BEE.?
Due to the recognition to their importance and worries about the future, the bee's disappearance problem has been gaining more media coverage over the years, which fill us with hope that it will receive more solutions like Let.it.bee. Due to the principle of modularity in synthetic biology, our project can also easily be adapted to other plants and pesticides in the future, by changing the tissue specific promoter and, if needed, the enzyme. Thus, after our preliminary tests the circuit could be expanded to more crops.
Brazil has suffered a lot from the COVID-19 pandemic, causing many of our lab experiments to be delayed. Although our current results and modelling are enough to understand more about our project, more tests are needed to better improve our circuit. You can check more of this journey on the Engineering page.
REFERENCES
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- PIRES, C. S. S.; Pereira, F. M.; Lopes, M. T. R.; Nocelli, R. C. F.; Malaspina, O.; Pettis, J. S. & Teixeira, E. W.. Enfraquecimento e perda de colônias de abelhas no Brasil: há casos de CCD? Pesq. agropec. bras., Brasília, v.51, n.5, p.422-442, May 2016. DOI: 10.1590/S0100-204X2016000500003
- BPBES. Relatório temático sobre polinização, polinizadores e produção de alimentos no Brasil. 2018.
- LEWIS, S. 25% of wild bee species have gone missing since the 1990s, study finds. Retrieved in Sept 19, 2021 from https://www.cbsnews.com/news/wild-bee-species-missing-since-1990s-extinction/
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- GRIGORI, Pedro. 118 agrotóxicos são aprovados durante a pandemia, liberação é "serviço essencial". Retrieved on Sept 18, 2021 from https://reporterbrasil.org.br/2020/05/96-agrotoxicos-sao-aprovados-durante-a-pandemia-liberacao-e-servico-essencial/
- HUNG Keng-Lou James, Kingston Jennifer M., Albrecht Matthias, Holway David A., Kohn Joshua R.. 2018. The worldwide importance of honey bees as pollinators in natural habitats. Proc. R. Soc. B. 285 2017214020172140. http://doi.org/10.1098/rspb.2017.2140
- BBC. Por que desaparecimento das abelhas seria uma catástrofe – e o que você pode fazer para evitar isso. Retrieved in Sept 20, 2021 from https://www.bbc.com/portuguese/geral-40220606
- PROJETO Abelhas Sem Ferrão. As possíveis causas do “desaparecimento das abelhas”. retrieved in Sept 20, 2021 from http://www.projetoabelhassemferrao.ufv.br/?noticias=as-possiveis-causas-do-desaparecimento-das-abelhas
- O’NEAL, S. T., Anderson, T. D., & Wu-Smart, J. Y. (2018). Interactions between pesticides and pathogen susceptibility in honey bees. Current Opinion in Insect Science, 26, 57–62. doi:10.1016/j.cois.2018.01.006
- IHARA, M., & Matsuda, K. (2018). Neonicotinoids: molecular mechanisms of action, insights into resistance and impact on pollinators. Current Opinion in Insect Science. doi:10.1016/j.cois.2018.09.009
- POTENZA, A. Bad news for bees: three-quarters of all honey on Earth has pesticides in it. Retrieved in Sept 20, 2021 from https://www.theverge.com/2017/10/5/16424216/honey-neonicotinoids-contamination-honeybees-pollinators-environment
- MUTH, F., Leonard, A.S. A neonicotinoid pesticide impairs foraging, but not learning, in free-flying bumblebees. Sci Rep 9, 4764 (2019). https://doi.org/10.1038/s41598-019-39701-5
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- TURCATTO, A. P.; Morais, M.M.; Almeida, J. M.V. & Jong, D. Importância dos nutrientes para o desenvolvimento das abelhas Apis mellifera. Retrieved in Sept 20, 2021 from https://www.apacame.org.br/mensagemdoce/121/artigo.htm
- SUCHAIL S, Debrauwer L, Belzunces LP. Metabolism of imidacloprid in Apis mellifera. Pest Manag Sci. 2004 Mar;60(3):291-6. doi: 10.1002/ps.772. PMID: 15025241.
- WU, YY., Luo, QH., Hou, CS. et al. Sublethal effects of imidacloprid on targeting muscle and ribosomal protein related genes in the honey bee Apis mellifera L.. Sci Rep 7, 15943 (2017). https://doi.org/10.1038/s41598-017-16245-0
- RANGEL, L.E.P.; Botton, M.; Papa, G.; Yamamoto, P. T. & Roggia, S. USO DE NEONICOTINOIDES NO BRASIL SITUAÇÃO ATUAL DOS PRODUTOS REGISTRADOS.
- EMBRAPA. Trajetória da agricultura brasileira. Retrieved in Sept 20, 2021 from https://www.embrapa.br/visao/trajetoria-da-agricultura-brasileira
- FIELDVIEW. Qual é a participação do agronegócio no PIB e nas exportações brasileiras? Retrieved in Sept 20, 2021 from https://blog.climatefieldview.com.br/qual-e-a-participacao-do-agronegocio-no-pib-e-nas-exportacoes-brasileiras
NÃO COLOCAR, É PRA ME GUIAR:
RASCUNHO:
https://www.beeornottobe.com.br/
http://managementjournal.usamv.ro/pdf/vol4_2/art2.pdf
https://www.nature.com/scitable/blog/green-science/global_crisis_honeybee_population_on/
Inspirações:
https://2021.igem.org/Team:Example2/Description
https://2019.igem.org/Team:Leiden/Description —> Wiki apontada como exemplo pelo iGEM
https://2020.igem.org/Team:Vilnius-Lithuania
Sugestão de citação e dados da Isa = https://ainfo.cnptia.embrapa.br/digital/bitstream/item/127056/1/Botton2014-Relacao-Agricultura-Apicultura.pdf