Acadian Plant Health’s molecular biologist, Timo van der Zwan, PhD, who manages the molecular biology laboratory, clarified the molecular modes of action of plant biostimulants using Ascophyllum nodosum extract. He shared with Oded Achilea, NAI contributing editor, the interesting story of the development process of these biostimulant products, based on the algae’s composition, physiology and mode of action.
The key benefits of brown algae (seaweed) Ascophyllum nodosum are related to the normal growth conditions of this organism. Living in the low and high tides of cold-water oceans inherently exposes it to salinity, drought, high differences in ambient temperatures and to extreme changes in light radiation intensity. However, very little is actually known about the mechanisms behind these effects.
The variable and complex nature of these substances makes it difficult to determine exactly which components are playing major roles in any specific plant reaction. Yet Bradáčová, et al (2016), showed that extracts, rich in zinc (Zn) and manganese (Mn), were able to augment cold resistance through enhanced oxidative stress tolerance. In this case, the protective effects of the algal extract likely stem from supplying plants with these micronutrients that play a role as co-factors in anti-oxidative enzymes.
Canadian company Acadian Plant Health is one of the pioneers in harnessing A. nodosum to its biostimulant production line, and has seen commercial success in producing and marketing its Ascophyllum nodosum extract (ANE)-branded products.
Timo van der Zwan, molecular biologist with Acadian Plant Health, established and manages the company’s molecular biology laboratory, clarifying the molecular modes of action of ANE plant biostimulants. His study has used several research tools, functioning at different levels, that help in deciphering the complex processes leading to its end results. These levels are genomic (based on the DNA information within the cell), transcriptomic (based on the m-RNA expressions of the DNA), proteomic (based on the proteins/enzymes, active in the cell's physiology), metabolomic (based on the variety of small molecules, found within the cells, biofluids and tissues of the organism, which are influenced by both genetic and environmental factors), and on phenotypic physiological expressions of the plants.
Genomic level response Dr. van der Zwan showed that when ANE was foliar-applied to hydroponically grown soybean plants that were challenged by a high concentration (50 millimolar (mM)) of sodium chloride (NaCl), their phenotypic expression to ANE featured 19 percent higher chlorophyll contents of the leaves, compared to plants that were challenged by NaCl, but were not treated by ANE. Ane-treated leaves also displayed 26 percent lower sodium contents compared to non-ANE treated plants. The explanation of these phenomena dwells at the genomic level, which revealed that a group of genes that enhance abscisic acid (ABA) production in the leaves, stems and roots, reacted within 24 hours after the ANE application, by an abrupt increased activity. Other genes that have shown a fast activity acceleration were genes known for their ability to sequester and remove sodium ions from the plant cell, and to enhance potassium cations uptake by the plant cell (see sidebar).
Proteomic level response When investigated at the proteomic level, it was found that ANE application triggered, within 24 hours, the production of specific proteins known for their salinity protection effect in all parts of
soybean plants. Furthermore, when investigated at the metabolomic level, it was found that ANE application prompted within 24-48 hours the accumulation of the amino-acid proline and of pinitol. Both are famous for acting as plant osmolytes (low-molecular weight organic compounds that maintain the integrity of cells when the ionic strength of their environment is too high). This shows, therefore, that an ANE application triggered an early beneficial plant response to the salinity stress, at all the above-mentioned levels, and thus markedly shortened the duration of the salinity stress and alleviated it.
Prime time A similar but more dramatic change took place when soybean seedlings were treated by the ANE product, and then challenged by a temporary drought stress followed by returning to normal watering management. Figure 1 shows the extreme phenotypic difference between the control plants, and the ones pretreated by ANE, whereby the first ones (left side of the figure) suffered serious dehydration, provoking a lethal ending, while the ANE pretreated ones could return to their normal functioning. Here again, the genomic investigation showed the central role of stress-inducible genes involved in the ABA production mechanism. This treatment of plants with the biostimulant before the stressful conditions took place is called "priming," and it is already employed commercially, also under field conditions. ●
For further explanation, the following paper provides an overview of how potassium and sodium cations (K+ and Na+) interact in a plant. In small quantities, sodium is a beneficial element as an osmolyte. However, at high concentrations, Na+ can inhibit physiological processes that then impair the growth of the plant. The ionic radii of Na+ and K+ in their hydrated forms are similar; under sodic conditions a failure in the discrimination among them often occurs, thus facilitating the Na+ influx through pathways that generally function for K+ uptake (Benito et al., 2014). Raddatz N, Morales de los Ríos L, Lindahl M, Quintero FJ and Pardo JM (2020), Coordinated Transport of Nitrate, Potassium, and Sodium. Front. Plant Sci. 11:247. doi: 10.3389/fpls.2020.00247.
Figure 1. ANE application to soybean plants dramatically enhanced their recovery from drought stress.
Source: Acadian Plant Health
Timo van der Zwan, Molecular Biologist, Acadian Plant Health
The African Plant Nutrition Institute (APNI) is a not-for-profit research and development organization founded in 2019 and based in Benguérir, Morocco. After two years, New AG International wanted to learn about the organization and how it has fared. Editor Janet Kanters spoke with APNI Director General Dr. Kaushik Majumdar.
How was APNI formed and why? The African Plant Nutrition Institute (APNI) was established in 2019 as a not-for-profit research and development organization through its founding support from the OCP Foundation and University Mohammed VI Polytechnic (UM6P), who recognized the overwhelming need to improve soil fertility and plant nutrition research and outreach in Africa. Despite being a new organization, APNI carries an established reputation through the expertise of its staff and the historical relationship with its predecessor organization, the International Plant Nutrition Institute (IPNI), which operated programs in Africa and throughout the world for many years up until the end of 2018. Many of IPNI’s researchers and educators have come together to lead APNI.
“Our group sees improved soil fertility and plant nutrition in African farming systems as an essential component to increase the availability of nutritious food in Africa as well as improving the livelihoods of African farmers and rural communities,” explains Dr. Kaushik Majumdar.
What are some project highlights? The past year has seen unprecedented global challenges yet APNI has marked progress in several projects across the continent. The 4R Solutions project, implemented in partnership with Fertilizer Canada, Cooperatives Development Foundation of Canada and local partners in Ethiopia and Ghana, was officially launched. APNI led the establishment of diagnostic trials in Ethiopia and Ghana that will be used as the basis for developing site-specific nutrient management practices guided by the principles of the 4R Nutrient Stewardship. “Our team assessed production constraints in key cereal cropping systems in Northern Ghana and in the Amhara region of Ethiopia based on a detailed agronomic survey data,” notes Majumdar. “On-farm nutrient omission trials were establishment for rice, maize and groundnut in Northern Ghana, and for wheat and teff in the Amhara, which will guide the development of site-specific fertilizer recommendations.” In a partnership with the Alliance for Green Revolution in Africa (AGRA), APNI is directing efforts to improve fertilizer recommendations in Kenya. Enhanced use of multi-nutrient fertilizers is providing an improved balance compared to current practice of applying fertilizers that supply only nitrogen and phosphorus. “The project implemented more than 100 fertilizer response trials for validating new fertilizer formulations and field demonstrations were established in 400 Kenyan villages,” says Majumdar. “Our outreach efforts extended to 60,000 farmers who were trained on best nutrient management and agronomic practices;
600 government extension workers trained to enhance their capacity for dissemination of information on balanced nutrient management; 1,000 private extension agents trained to provide last-mile agronomic services to compliment the Kenya government and mainstream extension; and 400 policy makers trained on the economic, environmental and social benefits linked to improved nutrient management.” Support continued for the fifth year of the Africa Cassava Agronomy Initiative (ACAI project). This project has been instrumental in increasing the availability of appropriate and affordable technologies to sustainably improve cassava productivity in the short- and long-term. “The cloud-based AKILIMO (from two Swahili words: Akili, meaning smart/intelligent and Kilimo meaning agriculture) system used to deliver agronomic advice for cassava production was upgraded and field validation work continued for site-specific fertilizer recommendations in Nigeria and Tanzania,” says Majumdar. “The project is also engaging the fertilizer industry to supply fertilizer blends for cassava production in Nigeria and Tanzania, and is working with national agricultural extension service providers to support and integrate AKILIMO into their extension programs.” APNI’s cross regional research and development initiative funded by the OCP Group supported the establishment of pilot research trials that are generating key datasets for guiding site-specific fertilizer for several crops including: maize and rice (East Africa), maize (West Africa), and wheat, rice, lentils, olives,
data palm and citrus (North Africa). In 2020, the combined cross regional projects were successful in disseminating knowledge on improved nutrient management practices to more than 5,000 farmers. “The project was instrumental in the development of the Nutrient Expert decision support system for wheat in Morocco, which is currently being used to deliver farm-specific nutrient management recommendations to smallholder and large-scale farms,” notes Majumdar. “Much of the research activities and delivery of research, extension and farmer training programs for wheat, lentils, olives and date palm are based on 4R Nutrient Stewardship (the science-based concept for best nutrient management practices).”
What challenges have you faced? Putting the profound challenges of the pandemic aside, the African continent continues to be confronted by food security and economic development challenges underpinned by poor agricultural performance. Concerted research and development investments over many years have yielded limited impact against the backdrop of complex socio-economic, policy and biophysical constraints. There is growing urgency for innovative and transformative solutions that are better designed to spur and fast-track the growth of agricultural sector and fully harness its potential. “Innovation in nutrient management research and development within the continent’s diverse set of cropping systems will be a key catalyst for unlocking Africa’s potential,” says Majumdar.
What are some of your planned projects going forward? APNI is excited about the enhanced prospects for research projects in 2021 as its explores new opportunities and rolls out new initiatives supporting its fresh research strategy. APNI recently developed its institutional strategy that will set its course for the years ahead. The resulting research program offers an innovative and business unusual approach – the strategy delivers effective, practical and actionable interventions for improving nutrient management for the much-needed sustainable transformation of agricultural landscapes in Africa. “Moving forward, APNI research programs are guided by three thematic areas that respond to the continent’s greatest challenges and opportunities for sustainable nutrient management,” says Majumdar. “Theme One (Climate and Weather-Smart Plant Nutrition) will work to generate farmer-centric plant nutrition strategies for changing weather and climate conditions; Theme Two (Soil Health for Improved Livelihoods) explores the link between plant nutrients and healthy agricultural systems and landscapes; and the overarching Theme Three (Precision Nutrient Management) supports its partners and farmers with evidence and information-management tools that can improve plant nutrient management.” APNI’s research program has a core focus on working with stakeholders to generate farmer-centric and applied research methodologies to capture and analyze nutrient and agronomic information and translate that knowledge into actionable and scalable practices that are applicable to a wide range of
cropping systems. The program focuses on cereal and tree-based cropping systems. The design and implementation of APNI’s research is guided by a cropping systems framework that aims to identify relevant systems-level plant nutrition interventions with high prospects for impact. Majumdar explained that APNI will embed methods and tools for monitoring critical performance parameters that reflect sustainability over time. “APNI’s research processes enables the incorporation of farmer knowledge, addresses issues of spatial and temporal variation of cropping patterns, the multiple functions of crop production systems, as well as climate, value chain and socio-economic drivers of change,” he notes. “The institute is integrating socio-economic research into its programs to enable the assessment of the social, economic and policy constraints that curtail fertilizer use and how systematic changes can be made to improve the adoption of effective nutrient, soil and crop management interventions.” As APNI unrolls its strategy in 2021, the organization will continue to engage in new partnerships. It’s team of plant nutritionists and agricultural systems experts are optimistic about the potential to unlock the potential of crop nutrition in Africa.
APNI pursues a vision of “Prosperous African farmers sustainably managing crop nutrition to provide consumers with a secure supply of nutritious foods at a reasonable price” with the help of its mission that strives to support “Enhanced plant nutrition for a resilient and food-secure Africa.”
The continental reach of APNI is delivered through its headquarters in Benguérir, Morocco, and its regional offices in Nairobi, Kenya; Yamoussoukro, Ivory Coast; and Settat, Morocco.●
Dr. Samuel Njoroge, APNI Program Manager, assesses improvements in maize growth and performance following application of 4R-based crop and nutrient management practices in on-farm 4R learning sites.
Dr. James Mutegi, APNI Senior Program Manager, explaining improved nutrient management strategies to Kenyan extension staff.
Farmer training sessions built a network of extension agents who will apply the technology and teach their peers to expand the reach and uptake of the AKILIMO advice tools in Tanzania and Nigeria.
Participatory field visits with farmers, researchers and extension workers, observing nitrogen deficiency symptoms for maize in the Savannah Zone in Togo during 2020.
Moroccan agronomists from OCP Group attending a short course organized by APNI on 4R nutrient management.
Photos: APNI
