From epiphytic to infection in phytopathogenic bacteria: the inherent risks of unstable weather conditions
Luis Romero FaúndezBionativa Technical Assistant Manager Bacteriosis does not appear spontaneously. Before any symptoms are manifested, we find phytopathogenic bacteria surviving and multiplying on the surface of the plant, particularly in stomata, trichomes, lenticellas or other natural openings. This phase, called epiphytic, constitutes a fundamental epidemiological stage where bacteria coexist with the host without causing visible symptoms, but retaining the ability to initiate infective processes under favorable environmental conditions (Hirano and Upper, 2000; Agrios, 2005). During this stage, microorganisms face a highly variable and hostile environment, characterized by fluctuations of ultraviolet radiation, temperature, humidity and availability of nutrients. Added to this is the competence exercised by the resident microbiome of the philosphere. These conditions limit the expression of genes associated with virulence and favor an ecological balance in which bacterial populations remain low levels compatible with the absence of disease (Vorholt, 2012; Xin et al., 2018). However, when favorable environmental conditions coincide, particularly moderate temperatures and high relative humidity, epiphytic populations can increase rapidly to critical densities. In these circumstances, a cellular communication mechanism called Quorum Sensing, through which bacteria collectively perceive population density and coordinate the activation of genes related to virulence, mobility, adhesion and production of compounds associated with infection (Hartmann et al., 2024; Zheng et al., 2025). Agrios, G.N. 2005 From this point of view, the climate not only influences its direct effects on temperature or humidity, but also because certain climatic sequences facilitate epidemiological events that transform an epiphytic population into a virulent-infectious population. A rain after a period of population growth can disperse the inoculum; tempered temperatures after frost can favor entry to damaged tissues; while warm and wet days increase bacterial multiplication and its mobility on the plant surface. Consequently, environmental conditions function as risk regulators and not simply as accompanying factors of the disease (Agrios, 2005; Xin et al., 2018). Communication mediated by Quorum Sensing is also closely related to the formation of Biofilms, Organized structures that allow bacteria to increase their survival, adhere to plant tissues and better resist stressful situations, such as lack of water, excess temperatures or tolerance to agrochemicals. It is also not by chance that the highest population densities are concentrated around stomata, lenticels, pruning wounds, frost injuries or bud openings, since these disruptions in the tissues constitute the main routes of entry to the plant (Hartmann et al., 2024; Krishna et al., 2022). From an epidemiological perspective, free water acts as the main bridge for the dispersion and infection of phytopathogenic bacteria, while the temperature regulates the speed of the physiological processes of both the pathogen and the host. Therefore, the climate should be understood as a factor that controls the transit between the presence of bacteria on the plant surface and the effective establishment of the disease. In carozo fruit trees for example for Chile, Pseudomonas syringae pv. syringae It is one of the main causative agents of bacterial cancer and to a lesser extent by Pseudomonas syringae pv. morsprunorum. These bacteria cause blight of flowers and darts, death of twigs, cankers and gummy exudations, generating significant economic losses in favorable seasons for the disease (Córdova et al., 2023). Once the infection is established, P. syringae It can colonize the intercellular spaces of the apoplast, modulate the defensive responses of the host through specialized secretion systems and produce toxins that contribute to the development of symptoms. At the same time, the production of exopolysaccharides favors adhesion-advancement by the tissues, allowing the progression of the disease at the local and systemic level (Xin et al., 2018; Krishna et al., 2022). Added to this unstable climate scenario is the growing concern about the appearance of populations with resistance to copper compounds or other bactericides traditionally used in agriculture. In the case of Chile, a history of resistance mainly to copper is handled both for Pseudomonas in cherry as Xanthomonas in walnut (d)Agurto, Esterio & Auger, 2000; Moya et al. 2018; Beltran et al, 2021) which requires strengthening preventive and integrated strategies, paying special attention to critical phenological processes such as sprouting and/or flowering, stages in which highly susceptible tissues and abundant opportunities for infection are generated associated with Micro-injuries-fissures typical of the aforementioned phenological processes. The practical implication is clear: the bacterial risk must be managed before the appearance of symptoms. In orchards with a history of bacteriosis, it is essential to reduce inoculum sources, reduce dispersion from infected plants, and use protection strategies that integrate chemical products (rational use), biological tools based on competition or antibiosis (rotate action mode), defense inducers (Complement) and cultural management aimed at reducing the opportunities for infection (modify conditions). No tool alone is sufficient when there is high epidemiological pressure. Finally, unstable weather conditions alone do not generate the disease, but they can synchronize the elements that make it very likely: elevated epiphytic populations, water dispersion, presence of wounds and susceptibility of the host. In a scenario where rain, heat, frost, dew and wind alternate, bacterial health should be understood as a dynamic risk management and not as a reaction after the symptom. The question is no longer simply “Is bacteria present?”, but rather “when will they find the right combination of climate, population density and gateways to transform into disease?” Bibliographic references Agrios, G.N. (2005). plant pathology (5th ed.). Elsevier Academic Press. Hirano, S.S., & Upper, C.D. (2000). Bacteria in the Leaf Ecosystem with emphasis on Pseudomonas syringae. Microbiology and Molecular Biology Reviews, 64, 624-653. Vorholt, J.A. (2012). microbial life in the phyllosphere. Nature Reviews Microbiology, 10, 828-840. Xin, X.F., Kvitko, B., & He, S.Y. (2018). Pseudomonas syringae: What it takes to be a pathogen. Nature Reviews Microbiology, 16, 316-328. Krishna, P.S., Woodcock, S.D., Pfeilmeier, S., et al. (2022). Pseudomonas syringae addresses distinctive environmental challenges during plant infection through the coordinated deployment of polysaccharides. Journal of Experimental Botany, 73, 2206-2221. Santamaría-Hernando, S., Cerna-Vargas, J.P., Martínez-García, P.M., et al. (2020). Blue-Light Perception by Epiphytic Pseudomonas syringae Drives ChemoReceptor Expression, Enabling Efficient Plant Infection. Molecular Plant Pathology, 21, 1606-1619. Hartmann, A., Binder,
Let’s talk about bacterial cancer – Nacillus, Mamull, Coraza
Did you know that wood diseases are the leading cause of plant death in fruit orchards nationwide? Ernesto Guerra, Technical and Commercial Zone Manager for Maule and Ñuble, shares crucial information about this challenge that affects all fruit trees. Don’t miss this video where you’ll learn how to protect your crops and ensure a healthier future for your plants.
Expert Tip – Get to Know Nacillus®
In the fight against bacterial cancer, business as usual isn’t enough. ⚔️🛡️ Daniel Vargas Campos, Regional RM and O’Higgins Norte, shares expert tips on Nacillus®. Break new ground with Nacillus®, watch the video! 📹
Bionativa – Summit Agro: Bio Insumos Nativa’s expansion plans after receiving investment from a Japanese group – Diario Financiero
We invite you to read the note that Diario Financiero wrote about our recent alliance with Summit Agro South America https://www.df.cl/df-lab/innovacion-y-startups/los-planes-de-expansion-de-bio-insumos-nativa-tras-recibir-inversion-de
Bio Insumos Nativa Strengthens Global Presence After Alliance with Sumitomo Corporation Group
Talca, april 30th, 2024.- With the aim of accelerating its global expansion, the Chilean company Bio Insumos Nativa has agreed to sell a portion of its shares to Summit Agro South America, dedicated to the development, distribution, and sale of agricultural products in South America, which is subsidiary of a Japanese conglomerate Sumitomo Corporation. This investment will be completed once the various required procedures are finalized. Sumitomo Corporation Group is one of the Japanese largest companies, with a global presence in various business areas, having over 40 years of experience in the sale and distribution of agrochemicals, fertilizers, and agricultural inputs in 40 countries. This investment will allow Sumitomo Corporation Group to expand its product portfolio and establish the entire value chain of the agricultural bio-inputs market. Meanwhile, Bio Insumos Nativa will benefit from access to new distribution channels and the expansion of its sales into new markets of interest. “This partnership will enable our company to accelerate the expansion process into major global markets. We are thrilled to welcome Sumitomo Corporation and its subsidiary, Summit Agro South America as our new partner, and together we will achieve significant milestones for the development of our businesses,” said Bio Insumos Nativa CEO, Paulo Escobar. The CEO emphasized that this alliance will be fundamental in leveraging the experience and distribution channels of Sumitomo Corporation Group and its subsidiary Summit Agro South America, expanding the brand’s presence worldwide. Bio Insumos Nativa is a leading company in the national agricultural market dedicated to the development and research, production, and sale of biological products (biopesticides, biostimulants, among others), with a presence in 11 countries. The company seeks to provide solutions to crop phytosanitary problems in Chile and worldwide, contributing to the production of healthy foods that are free of synthetic pesticides. Its commitment to quality, efficiency, and sustainability in the agricultural sector has been highlighted since its founding in 2002.
Bio Insumos Nativa: Chilean company leader in biological registrations in Brazil.
We are a Chilean company with 21 years of experience dedicated to the development, production and marketing of agricultural inputs of biological origin, which offer cutting-edge solutions to improve the productivity and protection of fruit trees, vegetables and crops in a natural and sustainable way. Our company has achieved a historic milestone in Brazil that makes us proud. We have become one of the Chilean companies with the most biological records in this country, expanding our commitment to sustainable agriculture in the world. Brazil has validated the quality, safety and effectiveness of our biological inputs, which meet the highest international quality standards. The entry into the Brazilian market adds to the internationalization of our operations that have successfully brought our biotechnological innovations to thousands of farmers in Peru, Ecuador, Panama, Guatemala, Nicaragua, Honduras, El Salvador, the Dominican Republic, and soon to Argentina, Mexico and the United States. We take this news as an impetus to continue developing, growing and offering the best solutions for different farmers in the world. We will not rest so that our products continue to be a sustainable and effective option, which optimizes agricultural production in order to obtain quality and waste-free food, now adding to the Brazilian market. We invite you to learn more about us, our history and products on the websites: Bionativa.cl / Bionativa.com.br. You can also follow us on our social networks on different platforms, where we share news, advice, testimonials and information about our products. Bio Insumos Nativa Chile and Bio Insumos Nativa Brasil, biological products for sustainable agriculture.
What’s coming in microbiology?: Changes, innovations and biologicals with greater prominence
Eduardo Donoso, phytopathologist and R&D director of Bio Insumos Nativa, shares his opinion regarding the topics that are most discussed in the field. Eduardo Donoso, phytopathologist and R&D director of Bio Insumos Nativa. There is an important demand from the markets to reduce waste and remove various chemical products from the programs, some significant for walnut trees, almond trees and other pits, such as the use of copper, where restrictions on its use are occurring, beyond of the possibility of residues remaining on the fruit, but because it is a heavy metal and generates a negative impact on the soil. The fungicide, Mancozeb, which is indicated for the prevention of numerous fungal diseases of a wide variety of crops, is also used to reduce the risk of resistance by pathogenic bacteria to copper, however it is one of the products that “comes “exit” from the market, since endocrine effects associated with Alzheimer’s have been seen. Currently, the European Community has already banned it, which will generate restrictions on its use in countries that export to that market. Along the same lines, copper restrictions are going to completely change the management of important diseases such as the Black Death, which currently has two or three applications in the central zone, which can be easily replaced with biologicals. On the other hand, in the south there are 16 to 18 applications per season, so it would be more difficult to solve. The complexity lies in the fact that they are old and cheap products, so all the other alternatives are much more expensive and a management strategy is required that allows the same level of control to be obtained with fewer applications of other products, since otherwise profitability would be reduced. Resistance inductor, one way What is quite strong in terms of management are products such as TANIRI (WP), a biostimulant based on Pseudomonas protegens, which acts as a natural growth promoter, improving plant development and helping to better cope with environmental stress conditions. in the tree. This resistance inducer causes the plant to generate defenses and with that an integrated control strategy is inserted, in addition to improving the control of the disease, not one hundred percent, but at a level that is acceptable. This is super interesting for walnut and almond trees, which ideally with fewer applications and wetting, better levels of control are achieved. This is all on an experimental level. “We hope that in two more seasons we will have consistent results with the resistance inducer.” If we make applications during pruning or leaf fall and colonize the buds with biologicals (Nacillus), regardless of when we do it, if it is before sprouting it will generate a significant impact on the level of incidence of the disease in the following season. . That has two interesting things, one that is innovative and two that allows you to start the season in better condition and that makes all the rest of the management easier. In the soil there is a transcendent opportunity because biologicals in the soil work excellently, better than chemicals in controlling diseases, but they also stimulate root growth and make plants much more efficient. Currently, we are seeing in cereals, tomatoes and potatoes that we can reduce fertilization up to half while maintaining the same yields, that reduces a lot of environmental impact, costs, since fertilizers are increasingly more expensive, and in turn with that It also lowers the carbon footprint since you replace a chemical. Generally it is replacing a kilo of chemicals with one of biological, but if you take out half of the fertilizers or 30% of them, you are talking about tons and that is less ships, trucks and less logistics moving all this, which already It does lower the carbon footprint. “There is a super important opportunity to lower costs and reduce the carbon footprint at the same time with applications that are very powerful to improve gardens.”.
Bacterial cancer
On this occasion, journalist Andrea Garrido talks with Eduardo Donoso, Director of Research and Development of Bio Insumos Nativa. How to prevent or detect bacterial cancer? What to do about this disease? We will tell you about it in the next chapter co-produced with Martínez & Valdivieso, official distributor of Bio Insumos Nativa.
Effect of Mamull (WP) on the control of Gnomoniopsis in chestnut trees
Eduardo Donoso, phytopathologist and R&D director of Bio Insumos Nativa, recounts his experience in this trial that he carried out together with José Pablo Correa, TriNuts chestnut advisor. Eduardo Donoso, phytopathologist and R&D director of Bio Insumos Nativa. Fungi are a constant problem in various crops, with this premise we decided to carry out a trial focused on a strategy of applying various biologicals to control Gnomoniopsis, a fungus that causes rot in chestnuts and also causes the leaves dry. Its presence causes post-harvest damage to rejected fruit and wood fungus. We carried out this test between 2019 and 2021 in orchards in two sectors of the country, Bulnes and Collipulli. It should be noted that the disease occurs when there are more rainy conditions. What we evaluated was a product called Mamull (WP), which is a biological fungicide that colonizes the points of cuts and wounds on the plant, preventing the entry of pathogenic microorganisms. Its strains present an effect of both competition, inhibition, and mycoparasitism. This product is used instead of painting pruning cuts, with Mamull (WP) these cuts are sprayed and colonized and wood fungi are prevented from entering, and it also eliminates the inoculum of the pathogen in the soil, either when the flower falls or the fruit from the previous year, the dead wood remains there as inoculums of these fungi. In this way, when applying it one colonizes it, reducing these sources of inoculum. Strategy Our strategy and execution began in the pre-flowering and beginning of flowering stage, where we applied Mamull to the leaf litter to control sclerotia and other reproductive structures and resistance to pathogenic fungi, both wood and fruit rot. Then, a resistance inducer was applied in tissues prior to infection that sought to increase the systemic response of the plant. After that, during flowering, Trichonativa was applied to colonize tissues susceptible to infection, prior to fruit formation. In order to continue in the pre-harvest stage where a resistance inducer was administered to increase the systemic response of the plant, to reduce the biotrophic infection phase, lengthening the puelche effect. To finish with the Mamull in the pruning period, where it was applied to the foliar pruning cuts and then to pruning remains in leaf litter, to avoid inoculum formation. Images of the trial and evolution of Gnomoniopsis in chestnut trees Positive results The results were quite good on the incidence of this pathogen and its impact on chestnut yield. There was, in fact, a significant decrease in damage; some orchards even took the treatment and duplicated it commercially. An orchard went from 73% incidence to 23%. As it was difficult to monitor the fruit at destination, we took samples of the treated and untreated fruit and took them to the laboratory and made a humid chamber, where we put them in conditions that favor the pathogen and from there we evaluated when the reduction in damage. Reduced disease damage level by 50% to 70%. A dissemination activity was carried out with the producers where we showed them the program and the results; currently some of them are applying it commercially.