Soil Microbiology and Plant-microbe interactions (2020/2021)



Course code
4S003259
Credits
6
Coordinator
Silvia Lampis
Academic sector
BIO/19 - MICROBIOLOGY
Language of instruction
Italian
Teaching is organised as follows:
Activity Credits Period Academic staff Timetable
Microbiologia del suolo e interazione microorganismo-pianta 4 II semestre Silvia Lampis

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Fondamenti di fisica e chimica del sistema suolo 2 II semestre Claudio Zaccone

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Learning outcomes

This course aims at elucidating the influence of the soil environment on settlement and activity of the microbial cenoses (microbiomes) in different pedological contexts. Within the completion of this course, students will have acquired a comprehensive overview of both the major phyla of microorganisms found in soil and the methods (including the new molecular high-throughput sequencing technologies) for their quantitative estimation as well as for the characterization of their physiological properties either in bulk soil or in the rhizosphere. Particular emphasis will be given to plant-microbe interactions, with a special attention to the multiple cross signaling mechanisms among plants and PGPR (Plant Growth Promoting Rhizobacteria) at the rhizosphere level. Symbiotic nitrogen fixation and different mycorrhizal associations will be discussed in deep details. Transformations of organic and inorganic pollutants mediated by soil microorganisms will be treated. Eventually, the understanding of soil microbial ecology principles will allow the students to correctly interpret environment-friendly strategies for improvement of crop productivity, biological control of plant pathogens and biodegradation/bioremediation of contaminated sites.


Syllabus

Foundamentals of soil science (2 CFU)
INTRODUCTION. The soil system and ecosystem services.
SOIL INORGANIC CONSTITUENTS. Main soil minerals: classification, crystalline structure, electrical charge formation and components. Phyllosilicates: 1:1, 2:1 and 2:1:1.
SOIL ORGANIC MATTER. Sources, nature and transformation processes of soil organic matter pools. Main properties and functions of soil organic matter.
PHYSICAL PROPERTIES. Texture, structure, density, porosity, colour, temperature.
CHEMICAL PROPERTIES. Cation exchange and anion adsorption: definition, mechanisms and models. pH: factors affecting soil pH, the buffering activity of soil, pH influence on element (bio)availability. pE: redox potential and main features of hydromorphic soils.
SOIL FLUID PHASE. Liquid and gas phase of soil.

Soil microbiology and plant-microbes interaction
Part I – The soil microbiome
Microbial biodiversity in bulk soil and rhizosphere. Methods for quantitative and qualitative (taxonomical) estimation of soil microbial populations. Measurement of biological activity in the soil: Microbial biomass, Metabolic reactions. Effects of physico-chemical and edaphic factors on soil microbial cenoses: Water content and availability, Soil pH, Oxygen concentration in soil atmosphere and redox potential, Concentration of nutrients, Xenobiotic compounds and heavy metals. Significance of soil microbial biodiversity to biogeochemical cycling.

Part II – Soil microbial interactions
Microbe-microbe interactions. Effects of microorganisms on plants. Effects of plants on microorganisms. Plant Growth Promoting Rhizobacteria (PGPR). Symbiotic diazotrophs: Rhizobia and association with legumes. Mycorrhizal associations: Ectomycorrhizae, Endomycorrhizae with particular emphasis to AM fungi, Ectendomycorrhizae.

Part III – Managing rhizosphere microbiome
Perspectives for the development of novel strategies for sustainable crop production, biological control of plant pathogens and environmental bioremediation through rhizosphere microbiome exploitation.

Assessment methods and criteria

The final exam consists of an oral interview (ca. 30 min of duration; generally 3 questions) on the topics developed during the course and will aim to ascertain both the concepts learned and the ability to link them and discuss implications. The exam method is the same for attending and non-attending students.

Reference books
Activity Author Title Publisher Year ISBN Note
Fondamenti di fisica e chimica del sistema suolo Sequi P., Ciavatta C., Miano T. (a cura di) Fondamenti di chimica del suolo (Edizione 3) Pàtron 2017 9788855533621
Fondamenti di fisica e chimica del sistema suolo Zaccone C. Materiale didattico fornito dal docente 2021 Slides delle lezioni.