Effects of fungal interaction with host plant and.pptx

Biological interactions are the effects that the organisms in a community have on one another
Microbial interactions are ubiquitous, diverse, critically important in the function of any biological community
The interactions between the two populations are classified according to whether both populations and one of them benefit from the associations, or one or both populations are negatively affected.

1. Effects of fungal interaction with host plant and other microorganisms- parasitism, symbiosis and commensalism Department of Plant Pathology, CSKHPKV Course Title: Advances in Mycology Course Code: Pl Path 601 Presented By: Kavita

2. Introduction Biological interactions are the effects that the organisms in a community have on one another Microbial interactions are ubiquitous, diverse, critically important in the function of any biological community The interactions between the two populations are classified according to whether both populations and one of them benefit from the associations, or one or both populations are negatively affected.

3. Host-microbe Interaction Plants are continuously subjected to both biotic and abiotic stress. There is a constant interaction between the pathogenic microbes and the host plant – the outcome of which determines resistance or disease Plants exude a variety of organic substances, resulting in a nutrient-rich environment that is conducive to microbial growth. Therefore, plants are highly colonized with a variety of microorganisms. Microbial communities influence plants in direct and indirect ways. Microbes that colonize plants are called either epiphytes (colonize plant surface) or endophytes (colonize plants interior).

4. Pathogenic relationship The extracellular area between the cell wall and plasma membrane serves as the initial battleground for plants and pathogens. The final relationship between the host and pathogen is determined by interactions between the proteins and other metabolites released by both the host and the pathogen. Pathogen types depending on their effects:

5. Symbiotic relationship Anton deBary 1879 defined symbiosis as “the intimate association between two distantly, related species that are mutually benefiting from this association.

6. This term was discovered by Pierre van Benden Mutualism is an obligatory positive interspecific interaction that is strongly beneficial to both species. In past, it was termed symbiosis. In this case, both of the species derive benefit and there exists a close and often permanent and obligatory contact which is more or less essential for survival of each. In this type, two populations enter into some sort of physiological exchange and resulted in coevolution of both species . Mutualism

7. The body of lichens is made up of a matrix formed by a fungus, within the cells of which an alga is embedded. The fungus makes available the moisture and minerals to the algae, which prepare food by photosynthesis. In nature, neither of the two can grow alone independently. They tend to grow abundantly on bare rock surface Lichens

8. Crustose lichen Fruticose lichen

9. Root nodule symbiosis (RNS) is a symbiotic interaction established between a host plant and nitrogen-fixing soil bacteria. This interaction results in the development of a specialized organ on the host plant called the root nodule, in which the bacteria are harbored intracellularly. Rhizobia normally live in the soil, but when there is limited soil nitrogen, legumes release flavonoids which signal to rhizobia Root nodules The rhizobia create ammonia from nitrogen in the air, which is used by the plant to create amino acids and nucleotides. The plant provides the bacteria with sugars

10. Mycorrhiza Mycorrhiza = means “fungus+ root” A symbiotic association between a plant and nonpathogenic fungus that colonizes the cortical tissue of roots during periods of active plant growth. Thus tree root become infested with fungal hyphae. The hyphae of the fungi help in phosphate solubilization thus providing nutrients to the trees while in return the trees provide shelter and food to fungi

11. Ectomycorrhiza Mycorrhizal association, the fungus produces a mantle or sheath over the fine lateral roots of the host tree and shoots some hyphae into the intercellular spaces of the outer cortex to form a so-called hartignet The fungi-covered lateral roots frequently adopt a bloated or coral-like appearance. Numerous forest trees, including conifers such as Pinus, Cedrus , and Abies and deciduous non-conifers such as oak, beech, birch, etc., develop ecto -mycorrhizal partnerships • Common genera of ecto -mycorrhizal fungi include Russula , Clitocybe, Boletus, Lactarius , and Tuber,

12. Endomycorrhiza Endomycorrhizal associations are more prevalent than ectomycorrhizal associations and are found in nearly all plant families. The fungi penetrate the root with growth between epidermal cells or through root hairs and invade cortex cells The spores of endomycorrhizal fungi have a thick wall, and under appropriate conditions germination will produce a germ tube with an emerging fungal cell.

13. Commensalism Commensalism is the interaction between two different species in which one species benefits and the other is neither damaged nor benefited by the relationship. The majority of examples of commensalism include feeding or protection Example: Barnacles cling to the whale or shark’s skin. The association helps the barnacle, which neither harms nor aids its host.

14. Ammensalism Ammensalism is the ecological interaction in which one species does harm to another without receiving any benefit in return. Example: Many species of fish and other animals can perish as a result of algal blooms, although the algae do not gain from their deaths. The roots of black walnut trees release a substance that inhibits the growth of nearby trees.

15. Parasitism It is a relationship in which one population (parasite) get benefited and derive its nutrition from other population (host) in the association which is harmed. The host-parasite relationship is characterized by a relatively long period of contact which may be physical or metabolic. Some parasite lives outside the host cell, known as ectoparasite while other parasite lives inside the host cell, known as endoparasite. Examples of parasitism: Entomopathogenic fungi Cordyceps fungi lives parasitically on the insect body

16. Interaction or collaboration between two or more individuals, substances, or other agents to produce an effect greater than the sum of their individual effects It is an association in which the growth of one organism either depends on or improved by the substrate provided by another organism. Examples of syntrophism : Methanogenic ecosystem in a sludge digester: Methane produced by methanogenic bacteria depends upon interspecific hydrogen transfer by other fermentative bacteria. The synergistic action of Lactobacillus bulgaricus and Streptococcus thermophillus in the production of yoghurt Synergism