Module 8: Plant-Microbe Symbioses Land and Sea

Plant Niches

Rhizosphere: Region of soil surrounding plant roots, significantly influenced by root secretions and the associated microbial community, playing a crucial role in plant (2-10 mm from the root)

Rhizoplane: Surface of the root **HAS A QUESTION ON EXAM IN LINE WITH MODULE 8 LECTURE Slide 25

Root endosphere: Area inside of the root

Phyllosphere: Area on the surface of the leaves

Leaf endosphere: Area inside of the leaf

Plant Microbiota

Plants provide a multitude of niches for the growth and proliferation of a diversity of microorganisms, including bacteria, fungi, protists, nematodes and viruses

Plant Microbiota emergent property

Manifestation of a trait in the community is an emergent property that cannot be predicted from the individual members

Yet overall soil disease suppressiveness is an emergent property that depends on multiple biotic and abiotic factors

The “winnowing” from soil to plant

“winnowing” of many bacterial and fungal genotypes to only a few succesful colonizers could be explained in part by plant-microbiome co-evolution

succesful colonizers inhabiting same host niche can compete for available resources or form stable co-existing communities through mutual cooperation

Symbiotic Benefits

Direct: Transformation and translocatino of essential nutrients in the soil to make them available to plants, mitigation of enviornmental stresses (drought) and protection from plant pathogens through competition

Indirect: Enhancement of a plant’s resistance responses

*Emerging paradigm in which interactions between plants and their associated microbiome should not be considered as inherently either beneficial or deleterious, but as a means to generate new phenotypes with increased fitness

Plant-microbe symbioses to solve enviornmental problems

Crops face:

Increase in heat or cold stress

Increase in dessication or flood

Increase in disease

Humans need metals for manufacturing

Valuable metals are destructive and costly to mine

Many sites have been stripped of their larger deposits