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Hermann Restrepo-Díaz

Agronomist, Doctor in Agricultural Sciences, research line Plant Physiology. Teaching responsibilities include undergraduate and graduate courses in the areas of plant physiology and crop production. Research responsibilities are focused on solving problems in agronomic and horticultural crops that can have significant economic, social and environmental impacts. Likewise, cooperating with grower associations, agricultural government agencies and farmers to develop and refine field methods to improve crop yield.

Cristhian Camilo Chávez-Arias

Agronomist, Master of Agricultural Sciences,research line Plant Physiology. Research experience focuses on the plant physiology of horticultural and agronomic crops, especially in understanding the effect of abiotic stress (heat, drought, waterlogging, nutritional deficiencies) on growth and development. Also understand the effect of mineral nutrition of plants on the physiology of crops to improve yield and productivity.

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Background and Aims

Climate change and variability alter the normal rainfall cycle causing the flooding of arable land and affecting agricultural production. Plants are highly susceptible to water stress due to waterlogging which affects their growth, development and yield. Cape gooseberry is an Andean fruit tree commonly grown in Colombia with a high susceptibility to hypoxic conditions in the soil. Foliar applications of compatible molecules can alleviate, help to tolerate and lessen the negative effects caused by different types of abiotic stress in several cultivated species. However, the use of this type of molecules in cape gooseberry to mitigate water stress has not yet been studied. The objective of this research was to evaluate the effect of foliar applications of the compatible molecules glycine betaine (GB) and hydrogen peroxide (H₂O₂) on the physiological and biochemical variables of cape gooseberry plants (Physalis peruviana L.) exposed to waterlogging conditions in the soil.

Methods

Two separate experiments were performed to study the effect of different GB and H₂O₂ doses in cape gooseberry plants exposed to two waterlogging periods. For both experiments, two-month-old cape gooseberry plants (five fully developed leaves) of ecotype 'Colombia' were used. In the first experiment, plants were subjected to a waterlogging period of six consecutive days and foliarly treated with a concentration of 25, 50 or 100 mM of GB and H₂O₂. Foliar GB or H₂O₂ applications were carried out at 0, 6 and 10 days after waterlogging (DAW). In the second experiment, the 100 mM dose was selected for both chemical compounds (GB or H₂O₂), which showed the best response to mitigate waterlogging stress in experiment 1. Plants were subjected to two waterlogging periods: i) a period established between 45 and 51 days after transplant (DAT), and ii) a period established between 63 and 69 DAT. Foliar GB or H₂O₂ applications were also performed at 0, 3, 6 and 9 DAW. Physiological and biochemical variables such as net photosynthesis rate, stomatal conductance, leaf water potential, relative chlorophyll content, PSII efficiency (Fv/ Fm), growth and canopy thermal index were measured.

Results / Outcomes

The results of the first experiment showed that the foliar application of GB or H₂O₂ at a concentration of 100 mM favored growth (stem length and diameter, leaf area and dry weight of the canopy), leaf temperature, stomatal conductance, PSII efficiency (Fv/Fm) and water potential in cape gooseberry plants exposed to a six-day waterlogging period compared to untreated waterlogged plants. Likewise, this group of plants had a higher tolerance coefficient to the waterlogging stress condition. In the second experiment, waterlogged cape gooseberry plants increased growth parameters (stem diameter, dry weight of the canopy and leaf area), net photosynthesis rate, stomatal conductance and chlorophyll content approximately 50 and 30% after foliar application of GB or H₂O₂, respectively, compared to untreated plants. Exogenous application of these two compounds (GB or H₂O₂) also favored the thermal index of cape goose plants subjected to two waterlogging periods.

Conclusions

This study showed that the use of compatible molecules such as GB or H₂O₂ helped cape gooseberry plants subjected to a hypoxic condition in the soil to cope with this abiotic stress condition by improving their physiological and biochemical response. Likewise, it was observed that the use of these two molecules (GB or H₂O₂) has positive effects on plant physiology since they favor net photosynthesis, stomatal conductance, leaf water potential, growth expressed in dry matter accumulation, stem diameter and leaf area, photochemical efficiency of PSII and chlorophyll content. The compatible molecules used in the present study at a concentration of 100 mM demonstrate an increase in the tolerance of cape gooseberry plants during the period of hypoxia in the soil. Finally, the obtained results suggest that exogenous applications of GB or H₂O₂ on cape gooseberry plants could be considered as an agronomic management alternative to help mitigate the negative impact generated by hypoxia conditions in the soil in cape gooseberry producing areas where waterlogging episodes can be expected.

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Presenting Author:

Jwan Hussein Mohammed Ibbini

Associate Professor of Environmental Microbiology

jhibbini@hu.edu.jo

Hashemite University

Faculty of Natural Resources and Environment

Department of Land Management and Environment

Zarqa – Jordan

Biography:

An associate professor of Environmental Microbiology. Earned her PhD from Kansas State University in 2008. Currently she is a Faculty at the Department of Natural Resources and Environment in Hashemite University in Jordan. Her experience involves teaching various courses in several universities in Jordan plus GCC country. Courses within core specialty relate to environmental sciences and mainly Soil and Water Microbiology classes. Her teaching philosophy focus on student based learning where students are also involved in the learning process, through which excellence in education is promoted. Her research has a multitude of interests ranging from bioremediation of contaminated ecosystems, exploring antimicrobial agents from natural resources, water decontamination and disinfection and recently interest is also developed in the area of biorisk management and safe science education.

Brief Biography for Rhonda Janke:

Dr. Rhonda Janke received her B.S. in Agronomy from Kansas State University, and her M.S. and Ph.D. from Cornell, in Ithaca, NY. Her career has combined the study crop science, soil science, and systems ecology with the goal of designing agro-ecosystems that are sustainable and resilient. She conducted research on organic farming systems at the Rodale Institute in Pennsylvania for 8 years, followed by 21 years of teaching, research and extension at Kansas State University. After completing a 5 month sabbatical at Hashimite University in Jordan in 2014, she accepted a position as Associate Professor at Sultan Qaboos University in Oman in 2015, where she teaches, vegetable production, organic agriculture and sustainable agriculture.

Background and Aims

Background:

Biochar (BC) is usually produced by pyrolysis which is the thermal degradation created by heating to temperatures between 250 ºC and 700 ºC of organic matter in the absence of air. In this study the biochar used in the fields was locally produced by a local company. Bio-char amendment to soils is a proposed strategy to improve soil fertility and mitigate climate change. However, before this can become a recommended management practice, a better understanding of the impacts of BC on the soil biota is needed, therefore, this work came to complement the chemical analysis in order to investigate the effect of Biochar management in the field in order to advance arid land management practices for soil quality and crop yield.

In this study the effect of BC application on soil microbial community was examined through the conventional Heterotrophic plate count method. Preliminary Results show that the BC amendment ranged from enhancing soil Fungi, Actinomycetes and Bacteria to no effect to the general count of soil microorganisms tested. Further statistical analysis waits to be done to analyze correlations to crop type and date of application. Therefore, final results will be presented during the final meeting.

Biochar properties and characteristics could vary due to plant material being used to synthesize it (Silber A., et. al., 2010). Recently its application as a soil amendment has been considered as a novel approach to enhance soil fertility, increase carbon sequestration in the soil and therefore, help mitigate greenhouse effect through slow release of the stable biochar carbon in the soil (Lehmann J., 2007).

Studies describe biochar as a recalcitrant material for microbial decomposition, they a advance soil fertility by reducing immobilization of valuable nutrients to plant when added to soil, rendering biochar as a viable long term carbon sink option for temperate agriculture (Kuzyakov Y., et. al., 2009). Furthermore, in situ application of biochar from olive mill waste was investigated and showed decreased metal contamination in soil (Hamid A., et. al., 2015).

Due to the inconsistency in the literature a deeper understanding of the biochar effect in the soil environment is required to facilitate decision making and allow for improved biochar application and management strategies. This study focuses on the biochar effect on soil microbial community, which in turn will affect nutrient cycling in the soil, plant growth and greenhouse gas emissions.

Aims:

The overall objective of this research project is to compare the effect of bio-char amended field sites to non-amended sites. Addressing the following questions:

- are the bio-char amended sites higher or lower in microbial activity as compared to control sites?

- are fungi, bacterial and other members of the soil microbial community present at similar levels, or do some categories of microbes dominate in one system or another?

- are there other changes in soil quality that can be measured that might also explain changes in the microbial community?

Methods

Several fields in Jordan were visited with previous history of biochar application. In each field soil samples from the tree/plantation zone treated with biochar was collected. Similarly, soil samples from the same field with no biochar application were considered as control. A composite soil samples were collected from top soil of 0-10 cm using a shovel and stored in plastic bags and transported to the laboratory these were considered as disturbed soil samples. Soil serial dilutions where prepared from each sample and cultured on a special media for heterotrophic counting for bacteria, actinomycetes and fungi. Following incubation microbial counts where recorded and compared with control samples for each field.

Results / Outcomes

Results obtained in this research show that usually bacterial counts predominate in the soil environment followed by Actinomycetes and then fungal counts. For example, the field of the mixed fruit orchard the colony forming units gram of control soil was (1,817*10⁸), (6,425*10⁷)and (3,71*10⁵ )for bacteria, Actinomycetes and fungi respectively. Thus, making bacterial community dominant in the terms of number. This result was noted in both control and biochar amended soil, unless otherwise a different trend is observed. This finding matches the facts known in the literature.

Results here show that the grape vine field showed the highest activity of biochar on the microbial community. This is perhaps due to application of zeolite along with biochar that could have a synergistic effect. An increase in bacterial counts was noted with biochar application in Date palm (Majhool) field and the eggplant field, while the bacterial and fungal population in these two fields were not significantly different from the control in the same fields. These finding could be due to recent application of biochar in these two fields.

In the field planted with Barhee date palm there seem to be a negative effect of biochar on microbial population, same effect was noted in the field planted with Date Palm and the field planted with oranges. No significant difference was noted in microbial population counts in the field planted with mixed fruit, as well as the field planted with date palm and the field planted with figs. See figure 1.

Conclusions

This project indicated that there is no consistency in the results provided from field applications of biochar on soil microbial biota. These results come in line with the inconsistent results in the litraure due to several factors such as type of plantation and biochar quantity and source material. Therefore further study on mineral content of the soil and the effect on a certain type of microorganism will help understand complex nature of below ground interactions upon Biochar application.

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Norma Soledad Erazo Sandoval was born in Riobamba, Ecuador, in 1962. She is a professional researcher and principal professor at Escuela Superior Politecnica de Chimborazo (ESPOCH), Ecuador. She holds a bachelor degree in agronomy, a Master's degree in Sciences, mention in Sustaible Agriculture at at ESPOCH; in 2017 Dr. Erazo got a PhD degree on Environmental Sciences from the National University of San Marcos, UNMSM, Peru. She has been the Head of the Agronomy Engineering Department at ESPOCH since November 2016.

Magdy Mileni Echeverría Guadalupe was born in Riobamba, Ecuador, in 1963. She is a professional researcher and principal professor at Escuela Superior Politecnica de Chimborazo (ESPOCH), Ecuador. She holds a bachelor degree in Chemistry at ESPOCH; a Master's degree in Sciences, mention in Environmental Management at UNACH; she got a PhD degree on Environmental Sciences from the National University of San Marcos, UNMSM, Peru. She has been the President of Research and Development Group for the Environment and Climate Change (GIDAC).

Gabriela Rosero Obando was born in Esmeraldas, Ecuador, she is an engineer graduated in Environmental Biotechnology at ESPOCH. She has been working as a researcher since 2017 in the Research and Development Group for the Environment and Climate Change (GIDAC); she was an international student in Biological Sciences at Brock University, Canadá under the ELAP 2017.

Juan Carlos Manzano Ocaña was born in Riobamba, Ecuador, in 1993. He is an engineer graduated in Agronomy at ESPOCH. Since 2017, he has been working as a Researcher Technician in the Research and Development Group for the Environment and Climate Change (GIDAC) in the Faculty of Natural Resources at ESPOCH.

Background and Aims

Microbial diversity has great importance to the planet because of its direct relationship with the biological, edaphic and environmental resources; but it has not been extensively studied in the Andean native forests of Ecuador. In this research, the microbial diversity from native forests located in Llucud and Palictahua parishes was determined through next-generation sequencing (NGS). In Palictahua, 27 phyla, 244 families, 719 genera and 828 species of bacteria, and 5 phyla, 58 families, 60 genera and 56 species of fungi were identified; in Llucud, 20 phyla, 201 families, 649 genera and 752 species of bacteria, and 4 phyla, 46 families, 49 genera and 38 species of fungi were identified. The physicochemical properties of soil were also determined and microorganisms were counted by the dilution method. Both forests are unique mountain ecosystems in the highland region, known and studied by many scientists, due to their great diversity of native flora and fauna, with Simpson indexes of 0.85 and 0.91 respectively (Caranqui, Salas, Haro, & Palacios, 2014); therefore, they can be considered genetic reservoirs of microorganisms with potential uses in several productive areas.

Microorganisms are the most numerous species on earth, their presence and activity is essential for the health and proper functioning of ecosystems; the degradation and transformation of organic matter is a clear example of microbial action (Olalde & Aguilera, 1998). Microbial diversity in soils is a good indicator of their fertility, not only because they are responsible for the degradation and recycling of organic matter, but also because they are responsible for maintaining the main cycles of fixation, uptake and release of some chemical elements and their main compounds (Capello et al., 2000). It is estimated that 99% of microorganisms cannot be easily cultivated; for this reason, the NGS technique increases the accessibility of genetic resources contained in a soil (Cadena et al., 2016).

This research was carried out with the objective of determining the microbial diversity of the native forests located in Llucud and Palictahua parishes, by checking if it is related to floristic diversity, the physicochemical characteristics of the soil, and natural phenomena such as exposure to volcanic eruptions.

Methods

Field Phase

Llucud has been classified as a highland evergreen forest; it is located at coordinates 9809532 S and 772114 E, at 2500-3600 masl, with an average annual temperature of 10 - 18 ºC, 500 - 1000 mm of precipitation / year, 70% of relative humidity (RH). Palictahua has been classified as an Andean brow forest; it is located at coordinates 9833340 S and 782832 E, near Tungurahua volcano, at 2700- 3410 masl, and with similar climatic characteristics to the Llucud forest. For microbiological characterization, and physicochemical analysis the soil samples were taken from the first 30 cm deep in the native forest of the two parishes.

Laboratory Phase

The laboratory analyses were determined from the methodologies established by the network of soil laboratories in Ecuador (RELASE). For the physicochemical analyses, simple samples of soil taken on field phase were used. The parameters analyzed were: texture, pH, electric conductivity (EC), organic matter (OM) and macronutrients (N, P, K). While the method of serial dilution was applied for the counting of microbial populations. For NGS the soil sample was homogenized and 200 mg were taken for DNA extraction with the SurePre Soil DNA Isolation Kit (Fisher Bioreagents, Fair Lawn, NJ (Bolger et al., 2014).

Results / Outcomes

Physicochemical properties of the samples from the Llucud and Palictahua forests and the microbial count of cfu/g soil.

Table 1. Physicochemical characteristics of the A horizon of the Llucud and Palictahua forests and number of cfu of bacteria, actinomycetes and fungi.

Molecular analysis by Next Generation Sequencing (NSG)

Bacteria and fungi identified in each forest can be seen in Table 2, while the taxonomic profiles are described in Krona software, which is launched on the web by downloading the shared files in the link: https://drive.google.com/drive/folders/1IPDbvVfWAT15U4YWo_yscByVwmi0UBxX?usp=sharing

Table 2. Summary of the number of phyla, families, genera and species identified in the Llucud and Palictahua forests

The physicochemical properties of soils are improved with the content of organic matter. In addition, the microbial biomass is also in better conditions, both of abundance, and in relation to the balance of beneficial/pathogens populations, when the soil presents more stable physical conditions, resulting in a higher biological activity of microorganisms (Jaurixje et al., 2013).

Llucud native forest possesses an excellent content of organic matter that is directly proportional to the macronutrient contents and the physical and chemical properties; while in the case of the Palictahua forest, although it presents a low content of organic matter, due to its greater tree diversity, it maintains a better stability in the soil. Both native forests have a high diversity with more than 20 phyla of bacteria which depends on the host and soil, with more than 200 ecological importance families. Regarding the diversity of fungi of both native forests, it is very high with more than 50 genera and more than 3 phyla.

Conclusions

This study shows that the Palictahua forest has greater microbial diversity than the Llucud forest, which could be related to three important aspects: the arboreal floristic diversity, the physicochemical characteristics of the soil, and the presence of volcanic activity such as the case of the Palictahua forest which is found in the foothills of the Tungurahua Volcano and the exposure to ashes could be exerting a positive effect. Although the Palictahua forest on average showed lower concentrations of N (53.09), P (42.12) and K (68.18); this was not an inconvenience to possess a high microbial diversity, as demonstrated by the results with NGS platforms.

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Dr. Kirsten Leiss. Focus on plant resistance and resilience based on morphological and chemical traits to develop markers, development of green plant protection products and targeted steering of resilience traits by abiotic and biotic factors to make susceptible plants mor resilient. PhD Plant Ecology University Fribourg (CH), Postdoc and subsequent Team Leader Host Plant Resistance at Plant Sciences and Natural Products Leiden University (NL), currently Senior Researcher Plant Health Wageningen University & Research,Horticulture (NL).

Dr. Johanna Bac-Molenaar. Emphasis on applied research in plant resilience of protected crops. PhD Plant Physiology and Genetics Wageningen University & Research (NL), Postdoc Plant Sciences and Natural Products Leiden University int the team of K. Leiss, currently Researcher Plant Health with K. Leiss at Wageningen University & Research, Horticulture (NL).

Dr. Rocio Escobar-Bravo. Focus on host plant resistance to pests based on trichomes and volatile production. PhD Molecular and Biochemical Biology at University of Malaga (ES), Postdoc Plant Sciences and Natural Products Leiden University in the team of K. Leiss, currently Postdoc Plant Sciences University Bern (CH).

Prof. Peter Klinkhamer. Professor Evolutionary Plant Ecology. Main interest in the key factors of plant trait evolution and the origin and maintenance of biological variation and their identification through plant fitness traits and selection in different environments. Emphasis is given on the study of how the genetic composition of an individual through its interaction wiht the environment is translated into the phenotype. Current research focusses on the diversity of secondary metabolites in plants. The main question is how the enormous diversity of secondary metabolites has evolved and is maintained and how this can contribute to the sustainable production of healthy foods, flowers and high-value bio-based products whereby increased reistance in ornamental and food plants forms a special focus.

Dr. Jaroslav Havlik. Emphasis on plant and food metabolomics with focus on Nuclear Magnetic Resonance Spectroscopy (NMR). PhD Quality of Agricultural Products at Czech University of Life Sciences Prague (CZ), Postdoc University of Glasgow (UK), Senior Lecturer and currently Head of the Metabolomics Department at Czech University of Life Sciences Prague (CZ).

Background and Aims

Mankind faces the need of feeding an increasing world population. This challenge comprises three components: increasing yield, sustainability of food production and promotion of health by means of food. Plant resilience and plant breeding play an essential role in reaching these ultimate goals. While traditionally breeding mainly focussed on high yield it is now clear that health and environmental issues become increasingly important. In both issues plant secondary metabolites play a critical role.

Plants synthesize an immense number of secondary compounds. This vast metabolic diversity is explained by a stepwise and reciprocal process of adaptation and counter adaptation between plants and their abiotic and biotic environment, moulded by mutual selection. As such plant secondary metabolites provide a huge reservoir for the generation of both plant defence and human health compounds.

Plant defence against pests and pathogens based on secondary metabolites has been weakened through selection of yield and consumer related traits. Crops and ornamentals are, therefore, in general, vulnerable to pest and pathogen attacks leading to an increasing demand of pesticides. Excessive use of pesticides has led to resistance of pests and pathogens, toxicity to non-target organisms, contamination of the environment and residue problems on marketable crops. This gained special importance due to new regulation regarding pesticide registration and application resulting in a decreased availability of pesticides.

In the framework of integrated pest management (IPM) we, therefore, developed an eco-metabolomic approach to identify profiles and secondary compounds related to host plant resistance to pests and diseases. As models we use western flower thrips (Frankliniella occidentalis) and powdery mildew (Podosphaera xanthii, Podoshpaera pannosa), both representing important plant health problems worldwide. Subsequently, these compounds can be used for 1) development of resistance markers assisting breeding 2) development of strategies to use abiotic and biotic factors to induce plant immune response and 3) development of external treatments for seed coating and dipping for cuttings.

Methods

Natural variation of crop and ornamental varieties resistant or susceptible to thrips and powery mildew are classified by in-vivo bioassays. Subsequently, their leaf and volatile metabolomic profiles are established using NMR (Nuclear Magnetic Resonance Spectroscopy) and GC (Gas Chromatography) respectively. These are, susequently, compared by multivariate statistics to identify secondary metabolites involved in host plant resistance. This approach has been used for tomato and carrot as vegetables and for chrysanthemum, gerbera and roses as ornamentals. For tomato we, subsequently, developed thrips resistance markers using a QTL approach based on multiple generations of a crossing betweeen a resistant and a susceptible variety. Furthermore, we conducted experiments with tomato and chrysanthmum to increase thrips resistance by application of UV light as an abiotic and infection with Pseudomonas syringae as a biotic factor. The later produces coronatine which is known to activate the Jasmonic acid pathway for defence against insects. Effects were measured by gene expression analysis and foliar metabolomics.

Results / Outcomes

In all host plant systems and both target organisms, trips and mildew, the metabolomic profiles of resistant and susceptible plants, as shown by the relevant PLS-DA score plots, were significantly different indicating a distinct metabolomic make-up in the resistant varieties. According to the concomitant loading plots a range of different metabolites were involved in resistance. The majority of these compounds were phenylpropanoids and flavanoids. Interestingly, these do not only have a negative effect on pests and diseases, but as anti-oxidants, are reported to show positive human health effects such as prevention of cancer and cardio-vascular diseases. For tomato we were able to establish 3 QTLs for thrips resistance on chromosomes 4, 5 and 10. Treatment with UV-light as well as with P. syringae lead to a substantial reduction of thrips damage as shown by increased expression of jasmonic acid genes and a subsequent rise of phenolic compounds.

Conclusions

The eco-metabolomics approach is of great relevance for the practical implementation of sustainable plant health measures. It enables the development of resistance markers for ornamental and crop breeding programms, whereby it provides unique possibilities to combine pest and disease management with dietary human health immprovement. Furthermore, it allows for the developement of natural crop protection agents and the use of abiotic and biotic elicitors for induced host plant resistance as important tools for growers to implement integrated pest management.