Question

Using examples to support your answer, write an essay on the biological and economic consequences of plant-fungal interactions, and how a better understanding of these interactions may lead to future bio technological applications.

Answer 1

In interaction with fungus the fungal partner secrete bioactive molecules such as small peptide effectors, enzymes and secondary metabolites which facilitate colonization and contribute to both symbiotic and pathogenic relationships. There has been tremendous advancement in fungal molecular biology, opening up new possibilities for the identification of key molecular mechanisms in plant–fungal interactions, the power of which is often borne out in their combination.

Plant health and its productivity is dependent on the microbial activity in the rhizopores and based on the type of microbes acting directly on the plant. This plant fungi partnership can provide stress tolerance to plants, provide disease resistance and also promote biodiversity in plants.On the counter aspect 70–80% of all plant diseases are caused by fungi, and it is proposed that approximately 10000 fungal species may induce diseases in plants.

Eg-economic importance of mycorrhiza with paddy. Since most of the countries have rice as their main diet.

B.cinerera that causes severe pre and post harvest damage

Puccinia species with can cause rust in wheat

Organisms like mycorrhiza and rhizobacteria can improve plan performance and crop productivity by inducing systemic resistance to phytopathogens and insect herbivores in plants. Biocontrol agents like mycoparasitic fungi can directly attack fungal plant pathogens.

Symbiotic AM fungi can act as natural fertilizers, enhancing plant yield, and as bioprotectants against pathogens and toxic stresses. Many important agricultural crops such as maize, potato, sunflower, wheat and soybean benefit from AM fungi, especially under nutrient-limiting conditions, since extensive hyphal networks in the soil improves the efficient uptake of orthophosphate and other minor nutrients.Marketed fungal biocontrol agents include fungi such as Ampelomyces quisqualis  for controlling powdery mildew on e.g. strawberry, tomato and grape, Coniothyrium minitans for the control of S. sclerotiorum in a variety of crops, non-pathogenic F. oxysporum strains (Fusaclean, Biofox) for suppressing pathogenic strains or Trichoderma spp., the latter being the most frequent and best studied fungal biocontrol agents applied in agriculture . Trichoderma strains used for biocontrol can establish themselves in the plant rhizosphere and act as opportunistic avirulent plant symbionts. They are marketed world-wide as biopesticides for the control of soil-borne and foliar fungal pathogens such as Rhizoctonia, Pythium, Sclerotinia, Botrytis and Alternaria. They are also biofertilizers and growth enhancers based on their ability to directly attack plant pathogenic fungi (direct antagonism or mycoparasitism) and promote plant growth, elicit plant defences against pathogen attack and environmental stress, and improve or maintain soil productivity (indirect antagonism).

Modification of plant defence system against microbial pathogens can improve disease resistant plants. It can be achieved through genetic engineering.