Periodic Reporting for period 1 - NANOSTIMULANTS (Biostimulants nanoencapsulation to increase yield under drought stress)
Reporting period: 2022-02-01 to 2024-01-31
The United Nations has set 17 goals for global sustainable development. Number two is the goal of zero hunger by 2030. To achieve this, agricultural production must be doubled, but some studies suggest that yield development will not be sufficient to reach this goal. One of the reasons for this is climate change. Moreover, heat waves, heavy rainfall and rising sea levels are predicted for the 21st century, with drought, floods and salinisation among the most critical consequences for food production. Today, abiotic plant stress is the main cause of severe yield losses of 50-80%, depending on the crop and geographical location. This is a major problem that needs to be solved in the coming years. This daunting situation is an excellent opportunity for plant scientists to apply their knowledge in an interdisciplinary way in agriculture to increase productivity under abiotic stress. In this regard, BS encompass a plethora of disciplines including chemistry, biochemistry, plant physiology, genetics and agronomy, which make for an interesting field of study. Biostimulants (BS) are extensively studied in plant science research. It is emphasised that they are an environmentally friendly way to manage biotic and abiotic stresses and increase food production, and their mode of action is being studied in depth.
A biostimulant (BS) is any compound, microorganism or mixture thereof, with the exception of fertilisers and pesticides. Biostimulants are usually environmentally friendly and inert to ecosystems. Their use is frequently reported in the literature to increase stress tolerance or to increase yield in the field2. In terms of plant health, BS are a good alternative to achieve the annual EU targets announced in the Communication: "A farm-to-table strategy for a fair, healthy and environmentally friendly food system". A good example of this way of thinking is the research carried out by the experienced researcher of this proposal. The use of L-pyroglutamic acid can save 30% of the water requirement and produce higher yields. However, to be effective, weekly treatments of 500 g per hectare are required. This means an additional cost of €20 per hectare per week to reduce irrigation by 30%, with some yield losses. One of the main reasons is probably the easy degradability of BS. Indeed, the application of pure bioactive compounds is also very limited due to their rapid release, low solubility and poor bioavailability5. An alternative to counteract these drawbacks is nanocapsulation. The present proposal is a novel interdisciplinary approach that aims to multiply the efficacy of BS by constructing a nanostimulant (nanoparticles encapsulating a BS ). It updates the traditional BS applications in this field by using the most advanced techniques of nanocapsulation (NE).
A biostimulant (BS) is any compound, microorganism or mixture thereof, with the exception of fertilisers and pesticides. Biostimulants are usually environmentally friendly and inert to ecosystems. Their use is frequently reported in the literature to increase stress tolerance or to increase yield in the field2. In terms of plant health, BS are a good alternative to achieve the annual EU targets announced in the Communication: "A farm-to-table strategy for a fair, healthy and environmentally friendly food system". A good example of this way of thinking is the research carried out by the experienced researcher of this proposal. The use of L-pyroglutamic acid can save 30% of the water requirement and produce higher yields. However, to be effective, weekly treatments of 500 g per hectare are required. This means an additional cost of €20 per hectare per week to reduce irrigation by 30%, with some yield losses. One of the main reasons is probably the easy degradability of BS. Indeed, the application of pure bioactive compounds is also very limited due to their rapid release, low solubility and poor bioavailability5. An alternative to counteract these drawbacks is nanocapsulation. The present proposal is a novel interdisciplinary approach that aims to multiply the efficacy of BS by constructing a nanostimulant (nanoparticles encapsulating a BS ). It updates the traditional BS applications in this field by using the most advanced techniques of nanocapsulation (NE).
The project started with the researcher being trained in encapsulation techniques at the C3NIMAT/I3N centre in Lisbon, under Prof. Joao Borges supervision. Where we develop our candidate nanostimulants. There he was introduced to different techniques such as encapsulation using ionic gelation and electrospray systems. After a literature review, the researcher introduced microcapsules made of alginate (derived from algae) to ensure future utility in practical applications (see https://doi.org/10.3390/plants12010055). With these techniques, the researcher obtained two different particles:
- Alginate microparticles by ionic gelation (Figure 1)
- Alginate microparticles by electrospray (Figure 2)
The three candidates were tested with tomatoes and corn in a controlled environment and showed that the properties of the biostimulant were improved by the encapsulation process.
Pyroglutamic acid encapsulated in alginate particles is able to increase tolerance to water deficits, requiring ten times less pyroglutamic acid, which increases the profitability of the treatment in the field. However, due to the early completion of the project, the results are not yet finalised, but we hope to have them available on the project website as soon as possible and also publish them in open access.
After the secondment, at Madeira´s University and in collaboration with Prof. Díaz Díaz from the University of La Laguna, the researcher produce nanoparticles from chitosan (which is extracted from crustaceans) using ionotropic gelation. We use in thi case menadione sodium bisulphite, another biostimulant with known shelf-life characteristics. We show how nanocapsulation increases plant tolerance to water deficits and improves treatment durability. You can see the full data in the manuscript at https://doi.org/10.1021/acs.jafc.2c07927.
The project was featured on various social media and in a local radio and television interview. The researcher also had some project presentations at the host university, at C3NIMAT/I3N and at the University of La Laguna. Finally, some of the results were presented in a paper at the Sustainable and Precision Agriculture Symposium 2022, which took place in La Laguna from 18 to 20 July 2022.
In addition to his work, the researcher also presented the Marie Curie programme and expressed his gratitude for the funding received to carry out the project.
- Alginate microparticles by ionic gelation (Figure 1)
- Alginate microparticles by electrospray (Figure 2)
The three candidates were tested with tomatoes and corn in a controlled environment and showed that the properties of the biostimulant were improved by the encapsulation process.
Pyroglutamic acid encapsulated in alginate particles is able to increase tolerance to water deficits, requiring ten times less pyroglutamic acid, which increases the profitability of the treatment in the field. However, due to the early completion of the project, the results are not yet finalised, but we hope to have them available on the project website as soon as possible and also publish them in open access.
After the secondment, at Madeira´s University and in collaboration with Prof. Díaz Díaz from the University of La Laguna, the researcher produce nanoparticles from chitosan (which is extracted from crustaceans) using ionotropic gelation. We use in thi case menadione sodium bisulphite, another biostimulant with known shelf-life characteristics. We show how nanocapsulation increases plant tolerance to water deficits and improves treatment durability. You can see the full data in the manuscript at https://doi.org/10.1021/acs.jafc.2c07927.
The project was featured on various social media and in a local radio and television interview. The researcher also had some project presentations at the host university, at C3NIMAT/I3N and at the University of La Laguna. Finally, some of the results were presented in a paper at the Sustainable and Precision Agriculture Symposium 2022, which took place in La Laguna from 18 to 20 July 2022.
In addition to his work, the researcher also presented the Marie Curie programme and expressed his gratitude for the funding received to carry out the project.
Early termination of the project will not prevent us from continuing to work on this project. In fact, after its completion, we have continued working with the particles and are now investigating the extent to which they are able to promote better tolerance after treatment compared to the free compound. as well as the accumulation dynamics of the biostimulant in the plant.
It will also be investigated whether the effect observed under controlled conditions translates into performance improvements under field conditions, for which the tests planned for the whole project will be carried out.
These results are expected to be published in open access during the coming year and will be available for consultation on the project website.
This project is part of one of the European Union's priority objectives, which is to use increasingly safe treatment methods in agriculture. Therefore, the results we have obtained are intended to be the first step in the study of the encapsulation of biostimulants in order to identify the benefits and problems that their use may bring under field conditions. This should open the debate on the use of encapsulation as a tool to help us improve the behavior of these substances in a more profitable and sustainable way.
An impact is expected on the agrochemical sector, especially in the field of biostimulation, where we have already received some contacts interested in the results of the project. The future of this project lies in public-private initiatives, with the present project being the cornerstone for deeper technological development.
It will also be investigated whether the effect observed under controlled conditions translates into performance improvements under field conditions, for which the tests planned for the whole project will be carried out.
These results are expected to be published in open access during the coming year and will be available for consultation on the project website.
This project is part of one of the European Union's priority objectives, which is to use increasingly safe treatment methods in agriculture. Therefore, the results we have obtained are intended to be the first step in the study of the encapsulation of biostimulants in order to identify the benefits and problems that their use may bring under field conditions. This should open the debate on the use of encapsulation as a tool to help us improve the behavior of these substances in a more profitable and sustainable way.
An impact is expected on the agrochemical sector, especially in the field of biostimulation, where we have already received some contacts interested in the results of the project. The future of this project lies in public-private initiatives, with the present project being the cornerstone for deeper technological development.