Microbiome Flashcards
when did plant-microbe interactions appear
fossil evidence suggests its at least 400 million years ago
what is a microbiome
combined genomic material of all microbial life interacting with a different multicellular eukaryotic organism
what is a plant microbiome
genomes of all organisms which interact with the plant on some level
what is genetic diversity
differences between multicellular eukaryotes or unicellular prokaryotes on a genomic level
what is a lateral gene transfer
movement of genes between 2 organisms which are not parent/offspring
what is the most common method of gene transfer in bacteria
lateral gene transfer
why do bacterial communities swap genes
to maximize number of adaptive genes
so 2 individual cells of the same species can differ significantly in the genome
how are microbial communities characterized
by their genes and the function of their genes
what are 3 regions of the plant microbiome
rhizosphere
phyllosphere
endosphere
what is the rhizosphere
microbial activity found below the soil surface
what is a hotspot for microbial activity
interface between plant roots and soil
what abiotic factors impact species diversity of microbes in the rhizosphere
SOIL
- salinity
- type
- pH
- structure
- organic matter
- disturbace
what biotic factors impact species diversity of microbes in the rhizosphere
root exudes
species richness/evenness in microbial community
species richness/evenness in plant community
what are root exudes
compounds released by the plant which directly impact microbial acitivity
what are examples of root exudes
secondary metabolites
hormones
sugars
what are the indirect beneficial effects of rhizosphere
presence of one species suppressing the presence of a pathogenic species or encouraging the presence of a beneficial species
what are the direct beneficial impacts of the rhizosphere
- can produce plant hormones that positively influence plant growth
- can produce enzymes directly linked to a reduction of stress hormones in the plant
- can facilitate the uptake of minerals
- can facilitate the uptake of water
- can be saprophytes (decomposers)
- can facilitate plant communication and kin support
what is the wood wide web
mycelial network that can pass nutrients from one individual plant to another
what is the plant disease trangle
disease severity linked to combination of 3 factors
- virulence of the pathogen
- tolerance of the host
- environmental conditions
what are environmental conditions impacts
can favor pathogen propagation
can limit defense response in host
what is hypovirulence
when virus slows down the growth of a fungus
reduced growth of the fungus allows the host plant to fight off the infection
traits of host tolerance
- genetically linked
- modulated by the presence of specific soil microbiota
direct effects of host tolerance
soil microbiota can secrete compounds which help increase the defence response in a plant and can induce plant systemic resistance
acts like an extended immune system
indirect effects of host tolernace
- microbes fight each other
- greater species richness in rhizosphere = fewer individual cells of a pathogenic species
- high species diversity in microbial communities linked to low disease incidence in plants
