October 31, 2022 - Botany Boost Blog

Effective Microorganisms (EM) in Sustainable Agriculture

by Sumudu HandunwalaOctober 31, 20222022 / Plant scienceLeave a Comment

Rapid human population growth leads to substantial development in agriculture production. Thus, large amounts of synthetic products are used to meet the demand for increased agricultural production. However, heavy usage of chemicals, pesticides, and antibiotics creates a burden on the environment, destroys the micro-fauna and flora in the soil, and causes threats to animals and human health. Therefore, sustainable agriculture production has gained global interest. In many ways, the application of effective microorganisms (EM) plays a vital role in sustainable production and has been widely spread throughout the world.

The EM is a fermented mixed culture of naturally occurring species of beneficial microorganisms that includes photosynthetic bacteria, lactobacilli, yeast, and actinomycetes in an acidic medium. After the concept of EM was initiated, different fertilizer manufacturing companies developed EM solutions to enhance crop production. This is an area where research and development activities are also abundant for long-term and short-term crop production. Promoting germination, flowering, fruiting, and ripening in plants; improving the physical, chemical, and biological environments of the soil, and suppressing soil-borne pathogens and pests; enhancing the photosynthetic capacity of crops and nitrogen fixation; ensuring better germination and plant establishment, increasing the efficacy of organic matter as fertilizer; and accelerating the decomposition of organic waste are some examples where EM could be used to gain an economic advantage in crop production. In the commercial use of EM, it could be found under different brand identities.

EM is eco-friendly, safe, organic and contains active microbes. EM solution is different from all the other agrochemicals in activity and composition. It is not necessary to put on goggles, masks, or protective clothing when spraying effective microorganisms. At the same time, effective microorganisms never pollute water systems. EM is considered mainly of the synthesizing type, which imparts beneficial effects on agriculture and environmental processes by generating a wide variety of bioactive substances. Since EM is easy to decompose after use, it never pollutes groundwater. Instead, it purifies soil, groundwater, lakes, and rivers, thereby reducing environmental burdens. The effective microorganism is compatible with various methods of farming, regardless of their scale.

However, some experiments reported that EM gives the best results when a natural imbalance of microorganisms has occurred and, in situations where the natural microorganism population is balanced and agricultural inputs are available, the addition of EM does not make a significant difference. Another argument emerging by scientists is the fact that applying EM to soil alters the natural chemical composition of the soil, displacing native microorganisms and nutrients, which may be harmful to the survival of native plant species Thus, and more research should be directed towards this aspect.

Advancements in the EM concept have paved the path to substitute synthetic products. Achieving sustainability in agriculture production using EM is directed basically to reducing the production cost, maximizing the profit, and protecting the environment, human and animal health.

References
Higa, Teruo (2001) ‘Effective Microorganisms in the context of Kyusei Nature Farming: a technology for the future’, in Proceedings of the conference on greater productivity and a cleaner environment through Kyusei Nature Farming, pp. 40–43.

Olle, M., and Williams, I. H. (2013). Effective microorganisms and their influence on 47 vegetable production–a review. The Journal of Horticultural Science and Biotechnology, 88(4), 380–386.

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Assembly of Microbial Community to the Improvement of Disease Resilience in Plants

by Shachini AnuradhaOctober 31, 20222022 / Plant biotechnologyLeave a Comment

Plants host diverse communities of microorganisms, also known as the microbiome, which colonizes various parts of host plants such as the rhizosphere, phyllosphere, and endosphere. The microbiome includes protists, fungi, bacteria, viruses, nematodes, etc. This highly complex assemblage of microorganisms has an important role in plant growth and health as well as in improving the productivity of crops by forming complex co-associations with plants. The plant-associated microbial communities confer multiple beneficial advantages to their host plants through nutrient acquisition, growth promotion, pathogen resistance, and environmental stress tolerance. Nowadays, a considerable amount of information is available on the structure and dynamics of the plant microbiome. The functional capacities of the isolated microbes have been identified using novel technologies.

The world population is estimated to rise to 9.5 billion by 2050, leading to high food demand. The availability of limited fertile land, urbanization, and climate change are some of the major constraints for the productivity of many crops. In addition, plants are subject to various biotic and abiotic stresses that limit their growth and productivity. The potential of the plant-associated microbial community to overcome biotic and abiotic stresses in plants can be interlinked to mitigate the current challenges in food security. For this, there is an urgent need to bring microbial innovations into practice.

Microbiome engineering is an emerging biotechnological strategy to improve the functional capabilities of native microbial species under biotic and abiotic stresses. It is a win-win strategy where both humans and the environment are benefited by improving crop yield and soil health. Conditioning the soil using suitable amendments, cultivating microbe-recruiting plant cultivars (host-dependent microbiome engineering), and inoculating synthetic microbial communities are microbiome approaches which improve plant health under stress conditions by increasing the functionally active and diverse microbial communities.

Figure 1 - Different microbiome engineering approaches

Figure 1 – Different microbiome engineering approaches

Traditional soil organic formulations such as compost, organic residues, organic waste, and peat can be used to support the growth and activation of beneficial soil microbes. Plant-oriented signaling molecules such as salicylic acid and metabolites in root exudates have a strong effect on the dynamics and the composition of the microbiome. It was suggested that these microbe-stimulating compounds can be artificially modulated and can be used as the soil conditioners.

Artificial microbial consortia (AMC) can also be used to improve the multiple functions relevant to crop plant growth and development. This strategy is the best alternative to solve the drawbacks of traditional bio fertilizers. Plant growth promoting rhizobacteria (PGPR) and AM fungi can also be artificially inoculated into soils to alter the structure of microbial communities. For example, inoculating chili plant roots with Bacillus amyloliquefaciens, Acinetobacter sp. and Bacillus velezensis have promoted the growth of chili plants and have shown the disease suppressive ability against Phytophthora capsica. Genetic engineering is also leading to the development of host-specific bio fertilizers.

References
Noman, M.; Ahmed, T.; Ijaz, U.; Shahid, M.; Azizullah; Li, D.; Manzoor, I.; Song, F. Plant–Microbiome Crosstalk: Dawning from Composition and Assembly of Microbial Community to Improvement of Disease Resilience in Plants. Int. J. Mol. Sci. 2021, 22, 6852. https://doi.org/10.3390/ijms22136852

Albright, M.B.N., Louca, S., Winkler, D.E. et al. Solutions in microbiome engineering: prioritizing barriers to organism establishment. ISME J 16, 331–338 (2022). https://doi.org/10.1038/s41396-021-01088-5

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Featured image – https://www.farmersnational.com/Blog/Agricultural_Real_Estate/What_is_the_Best_Auction_Method_for_Selling_Land/

Figure 1 – Noman, M.; Ahmed, T.; Ijaz, U.; Shahid, M.; Azizullah; Li, D.; Manzoor, I.; Song, F. Plant–Microbiome Crosstalk: Dawning from Composition and Assembly of Microbial Community to Improvement of Disease Resilience in Plants. Int. J. Mol. Sci. 2021, 22, 6852. https://doi.org/10.3390/ijms22136852

Microbes as Biological Control Agents

by Ruwini AsankaOctober 31, 20222022 / MicrobiologyLeave a Comment

Biological control of plant pathogens is referred to as controlling disease causing organisms (pests) such as insects, mites, and weeds; using another beneficial organism. This is one of the best sustainable methods of plant disease management, instead application of agrochemicals.

The use of chemicals is a major practice of controlling pathogens in today’s world, to address the issue of losing crop quantity and quality due to plant diseases. Pesticides, insecticides, weedicides, and fungicides are the main types of agrochemicals used during crop cultivation and post-harvest management of food products. So far, chemicals have achieved a high rate of success in controlling plant pathogens, but it always comes at a cost.

Environmental problems and health related problems are the direct costs of using agrochemicals. Other than that, chemicals produce resistant pathogens making their control even more challenging.

This has created a requirement for sustainable disease control mechanisms to make sure that the present and the future of food production are in a safe zone, to feed the skyrocketing human population.

Fungus, bacteria, viruses, or a mixture of two or more microorganisms are used to control pathogenic organisms. Microbial biological control agents act via a range of modes of action in controlling pathogens.

Some microbial biological control agents compete with pathogenic microbes for nutrients, habitat, or optimum growth conditions. Obligate biotrophic pathogens infect living host cells and do not depend on nutrients from the outside environment. Necrotrophic pathogens kill the host tissues and utilize the available nutrients in them. Whereas some other pathogenic microbes depend on exogenous nutrients where they have to compete with other microbes. If the microbiome is already invaded by a biocontrol beneficial microbe with good genetical potential, the pathogen has to compete to colonize. Currently, recombinant DNA technology is used to develop such biological control agents with several beneficial characteristics.

Antagonists acting through hyper-parasitism and antibiosis directly interfere with the pathogen. Hyperparasites invade and kill mycelium, spores, and resting structures of pathogenic bacteria and fungi. Such interactions between pathogens and biological control agents are regulated through various metabolic functions. Compounds such as enzymes, different signaling molecules, antibiotics, and other antimicrobial metabolites are produced when the biocontrol agent interacts with the pathogen. Production of secondary metabolites with anti-pathogenic properties at low concentrations in situ supports biological control agents to obtain a competitive advantage to colonize, absorb nutrients, and thereby, spread their colonies.

Highly effective microbes against pathogens can be selected to culture them on artificial media to be utilized at a mass scale during the growing season once or several times. Biocontrol products that are manufactured commercially by companies sometimes contain living microbes. On the other hand, some biocontrol products only contain antimicrobial metabolites extracted by biological control agents. In most cases, antimicrobial metabolites are produced by antagonists directly on the spot where the pathogenic target is present, so screening such antimicrobial products can only be done when the correct target interacts with the biocontrol agent.

It is expected that complex chemical communication happens within and in between microbiomes and plants including the contribution of signaling by microbial biocontrol agents to the continuous chemical crosstalk between organisms in the environment. It helps in inducing resistance in plants (MAMP triggered immunity) so that the pathogen is defended with a selective pressure and the pathogen may have to overcome to cause the disease in the host plant.

The future of microbial biocontrol agents depends mostly on better screening assays for finding the next generation with more capabilities to address the issue of less productivity of polluted and chemically treated land. Biological remediation of dumped and polluted lands is the hope of not only microbial biocontrol agents, but also all the beneficial microbes. Multi-omics for a better understanding of complex events in the microbial world can make the use of microbes in a correctly defined manner so that maximum efficiency is obtained.

Reffernces
Teixidó, N., Usall, J. et al. (2022). Insight into a Successful Development of Biocontrol Agents: Production, Formulation, Packaging, and Shelf Life as Key Aspects. Horticulturae, 8(4), 305.

Velivelli, S. L., De Vos, P. et al. (2014). Biological control agents: from field to market, problems, and challenges. Trends in Biotechnology, 32(10), 493-496.

Lahlali, R., Ezrari, S. et al. (2022). Biological control of plant pathogens: A global perspective. Microorganisms, 10(3), 596.

Köhl, J., Kolnaar, R. et al. (2019). Mode of action of microbial biological control agents against plant diseases: relevance beyond efficacy. Frontiers in plant science, 845.

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White Fly Attack and Future of Coconut Cultivation

by M.E.U.K. PereraOctober 31, 2022October 31, 20222022 / Plant scienceLeave a Comment

Coconut (Cocos nucifera ) is one of Sri Lanka’s three major export crops, bringing home a total revenue of US$537.62 million in 2014. Known for its great versatility, the coconut tree is one of the most important plants in Sri Lanka.

The Sri Lankan lifestyle has been inextricably intertwined with the Coconut tree, not just for the milk, water, and oil-giving nuts, but for the leaves, the trunk, and the fibrous husk that surrounds the coconut. There is no part of the coconut tree that goes to waste in a Sri Lankan household. There are three types of coconuts in Sri Lanka: tall coconuts, dwarf coconuts, and King coconuts.According to figures published in December 2018 by the Food and Agriculture Organization of the United Nations, it is the world’s fourth largest producer of coconuts, producing 2,623,000 tonnes in 2018. Because of the value of the coconut in Sri Lanka, it is named “Kapruka”, which means the crop gives every wish.

In all but the upper elevations of Sri Lanka, coconut palms are found. It is a demanding, sturdy, and light tree. In the triangle created by Puttalam, Kurunegala, and Gampaha, the coconut is primarily found. The Coconut-Triangle is the name given to the region in which these three settlements are located.

Figure 1 - Coconut tree

Figure 1 – Coconut tree

Coconut Whitefly (Aleurodicus cocois) damage
This insect is known in Sri Lanka by various names, such as powdery mildew, whitefly, and white bug. About 1 mm in length, this pest lives in herds, sucking the sap of various plants. In addition to coconut, the insect attacks plants such as bitter gourd, watermelon, snake gourd, belonging to the Cucurbitaceae and peanut, cowpea, and beans, belonging to the Leguminosae, also being affected. In addition, it acts as a carrier of viruses or fungi and causes huge damage. At higher temperatures, their activity is somewhat stronger.

This white-colored insect penetrates the leaflets of coconut seedlings and mature coconut trees and then damages the coconut plant by sucking the sap out of them. They belong to the phylum Arthropoda class and have four basic stages in the life cycle. On the underside of the leaves of the coconut tree, many stages of the life cycle of this insect can be seen with the naked eye.

Figure 2 - white fly (Aleurodicus cocois)

Figure 2 – white fly (𝘈𝘭𝘦𝘶𝘳𝘰𝘥𝘪𝘤𝘶𝘴 𝘤𝘰𝘤𝘰𝘪𝘴)

Control of white fly damage
There are two methods recommended by the CRI to control the coconut white fly attack.

The first method is the physical method. In this method, manual removal has to be done. Application of pressurized water to wash away the underside of the leaves well also removes the white flies.

Because these white flies are drawn to yellow, using yellow polythene with grease applied is another strategy for population control.

The second method is the chemical method, and in this method, the application of recommended chemicals can be done. For instance, the application of a dissolved solution of 3g of Thiamethoxam or 20ml of carbosulfan or 2.5 g of an insecticide containing chlorantraniliprole in 10 liters of water, using a sprayer, thoroughly wets the underside of the leaves of the plant.

References
https://www.srilankabusiness.com/blog/multiple-products–made-from-coconut-tree.html
https://en.wikipedia.org/wiki/Coconut_production_in_Sri_Lanka#cite_note-2
https://en.wikipedia.org/wiki/Coconut_production_in_Sri_Lanka#cite_note-5

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Featured image – https://m.indiamart.com/proddetail/detergent-surf-for-palm-tree-and-coconut-trees-for-white-fly-effect-21836262973.html
Figure 1 – https://www.srilankabusiness.com/blog/multiple-products–made-from-coconut-tree.html
Figure 2 – https://goodhands.lk/coconut-whitefly-damage-aleurodicus-cocois/

Sustainable Use of Biopesticides and Biofertilizers in Agriculture

by Dhananji RupasingheOctober 31, 2022November 1, 20222022 / Plant biotechnologyLeave a Comment

Biotechnology is the technology that utilizes biological systems, living organisms or parts of these to develop or create different products. The application of microbes in sustainable agriculture and the environment is a rapidly growing segment in the novel world. Increasing food demand poses a great challenge to the traditional agriculture system. While the development of biotechnology applications began in 6000 BC., the development of genetic tools and cellular engineering was initiated in 1970. Genetically modified (GM) crops that are resistant to many pathogens and weeds have contributed to the increase of high yields in agriculture.

Biofertilizers are the preparation of live or latent cells of efficient strains of microorganisms used for application to accelerate the process of plant growth and development. They can add 20-200 Kg N/ha per year under optimum soil conditions and thereby increase the total crop yield by 15-25%. Rhizobium BGA, Azotobacter sp., Gluconacetobacter spp. stimulate the production of growth-promoting substances like Vitamin-B complex, Indole acetic acid (IAA) and Gibberellic acid. Phosphate solubilizing/mobilizing biofertilizers solubilize/mobilize about 30-50Kg P₂O₅/ha. Azotobacter inoculants applied to non-legume plants promote seed germination and the initial vigor of plants. Phosphate ions (PO₄^3-) mobilize the Mycorrhiza (VAM fungi) and enhance the uptake of P, Zn, S & water leading to uniform crop growth & enhancing resistance to disease & hardiness of transplant stock. They act as antagonists and suppress the incidence of soil-borne pathogens thus helping in the control of diseases. Biofertilizers improve the physical properties, tilth, productivity and health of the soil. Nostoc, Anabaena and Scytonema have reclaimed the alkaline soils. Cellulolytic and ligninolytic microorganisms enhance the degradation/decomposition of organic matter in the soil.

Biopesticides are microbes possessing invasive genes that can attack the defense genes of weeds by killing them. Endospores of the Bacillus thuringiensis (Bt) are used as an organic pesticide because some strains produce crystals in the endospores that are toxic to insects when they consume endospores. Controversial crop plants are genetically modified with the Bt toxins genes to develop resistance to pests. Bioherbicides can persist for a long time in the environment which can exist for the upcoming growing season and affect target pathogens only. Seed coated with inoculants can be developed to protect the plants during their critical seedling stage.

Bioinsecticides are naturally-occurring substances from different sources that control insect pests. They are low toxicity to non-target microorganisms, easily degradable, highly effective in small quantities and effect on target pests only. The bioinsecticides contain microbes such as Beauveria bassiana, Metarhizium anisopliae or brunneum and Isaria fumosorosea contact with pests, affect the nervous and muscular system, paralyzing and eventually killing the insects and mites.

Bioremediation is the process that makes use of microorganisms to eliminate pollutants from soil. Microorganisms can sequestrate toxic metals by cell wall components, alternating biochemical pathways to block metal uptake, converting metals into innocuous forms by enzymes, enhancing the mobility by siderophores and reducing the availability of heavy metals. Desulfovibrio desulfuricans convert sulphate to hydrogen sulphate that reacts with heavy metals to convert an insoluble form of metal sulphides. The genetically modified strain of P. fluroscences HK 44 is able to sense pollution, signaling through bioluminescence.

Figure 1 - Role of biofertilizers and biopesticides in organic farming

Figure 1 – Role of biofertilizers and biopesticides in organic farming

References

Binte Mostafiz, S., Rahman, M., Binte, S., Rahman, M. and Rahman, M. (2012). Biotechnology: Role of Microbes in Sustainable Agriculture and Environmental Health Quantification and analysis of Somatic embryogenesis receptor like kinase gene expression on Malaysian Indica rice View project Low carbon pathways_GUP_UTM JB View project The Internet Journal of Microbiology Biotechnology: Role of Microbes in Sustainable Agriculture and Environmental Health. Agriculture And Environmental Health. The Internet Journal of Microbiology, [online] 10(1). doi:10.5580/2b91.

Dhir, B. (2017). Biofertilizers and Biopesticides: Eco-friendly Biological Agents. Advances in Environmental Biotechnology, pp.167–188. doi:10.1007/978-981-10-4041-2_10.

Berg, G. (2009). Plant–microbe interactions promoting plant growth and health: perspectives for controlled use of microorganisms in agriculture. Applied Microbiology and Biotechnology, 84(1), pp.11–18. doi:10.1007/s00253-009-2092-7.

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Featured image – https://www.peptechbio.com/blog-biofertilizers/
Figure 1 – https://www.sciencedirect.com/science/article/pii/B9780128223581000092

Nano-technology in Micro-biology

by A.A.A.U. AberathnaOctober 31, 20222022 / MicrobiologyLeave a Comment

Nano microbiology, which is a rapidly evolving field of research, exists at the crossroads of biology and nanoscience. Nanotechnology is a state-of-the-art technique of using particles between 1 to 100 nm, which originated as both organic and inorganic forms. Nevertheless, the size and shape depends on the method and the materials used in the fabrication process. The particle size is important because the physicochemical stability and biological activity of the particles depend on the size.

Various physical and chemical methods are broadly used for the synthesis of nanoparticles. Though these approaches offer higher production rate and better size control over the synthesized nanoparticles, they are considered unfavorable due to high capital cost, energy requirements, anaerobic conditions, use of toxic reagents and the generation of hazardous wastes. These downsides obscure the down streaming processes, raise production cost and cause apprehensions about the environment. Moreover, the chemically synthesized nanoparticles are less biocompatible and use of toxic chemicals for synthesis and lack of stability has limited their use in clinical applications. Therefore, development of environmentally safe, economical, and biocompatible procedures for synthesis of nanoparticles are desired. Synthesis of nanoparticles by biological means offers cheap, nontoxic and eco-friendly alternatives to their counter physical and chemical methods. Microbes are found to be tiny nano-factories and microbial synthesis of nanoparticles has merged biotechnology, microbiology and nanotechnology into a new field of nano-biotechnology. Metal–microbe interactions have been widely used for bioremediation and bioleaching biomineralization, but nano-biotechnology is still at its infancy. Owing to its potent benefits it may have promising applications in nano-medicine.

For biological synthesis of nanoparticles, microbes have been exploited all over the globe. Microbes like bacteria, fungi and yeasts are mostly preferred for nanoparticle (NPs) synthesis because of their fast growth rate, easy cultivation and their ability to grow at ambient conditions of temperature, pH and pressure. Owing to their adaptability to metal toxic environments, microorganisms possess intrinsic potential to synthesize nanoparticles of inorganic materials by following reduction mechanisms via intracellular and extracellular routes. Microbes trap metal ions from the environment and turn those metal ions into the elemental form using their enzymatic activities.

Figure 1 - Microbial synthesis and applications of nanoparticles

Figure 1 – Microbial synthesis and applications of nanoparticles

Bacteria can remarkably reduce heavy metal ions to produce nanoparticles. Researchers have demonstrated bacteria mediated interactive pathways responsible for metal ion reduction and their ability to precipitate metals on nanoscale. A major advantage of bacteria-based nanoparticle synthesis is their large scale sustainable production with minimal use of toxic chemicals, however there are certain limitations like laborious bacterial culturing processes, less control over their size, shape and distribution. Fungi also possess various intracellular and extracellular enzymes capable of producing mono-dispersed nanoparticles. Yield of nanoparticles is high in fungi as compared to bacteria due to relatively larger biomass. Various fungal species like Verticillium luteoalbum, Colletotrichum sp., Fusarium oxysporum, Trichothecium sp., Aspergillus oryzae, Alternaria alternata, Trichoderma viride etc., have been reported to produce nanoparticles with diverse shapes and sizes, which can be used in a vast range of applications.

References

Adegbeye, M. J., Elghandour, M. M. M. Y., Barbabosa-Pliego, A., Monroy, J. C., Mellado, M., Ravi Kanth Reddy, P., & Salem, A. Z. M. (2019). Nanoparticles in Equine Nutrition: Mechanism of Action and Application as Feed Additives. Journal of Equine Veterinary Science, 78, 29–37. doi:10.1016/j.jevs.2019.04.001

Fariq, A., Khan, T., Yasmin, A. (2017). Microbial synthesis of nanoparticles and their potential applications in biomedicine. Journal of Applied Biomedicine. http://dx.doi.org/10.1016/j.jab.2017.03.004

Joye, I. J., Davidov-Pardo, G., & McClements, D. J. (2014). Nanotechnology for increased micronutrient bioavailability. Trends in Food Science & Technology, 40(2), 168–182. doi:10.1016/j.tifs.2014.08.006

Rai, H.K. and Rai, P., 2018. Solar Energy Harvesting Using Nanotechnology. International Journal of Applied Engineering Research, 13(6), pp.348-353.

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