MYCOLOGY 3 - FUNGI IN AGRICULTURE AND FOOD INDUSTRY

Question 1

what is white nose syndrome and how does it work?

Answer 1

the fungus is Pd, an ascomycota
lives in caves, loves the cold
the host is bats
kills 5 million bats a year, kills 70-100% of the infected hibernaculum
this is a mycovirus: infects fungi, small pieces of RNA, encodes the fungi and take over
this mycovirus is uniquely found in north american Pd isolate, makes Pd more virulent
the bat is hibernating: cold, metabolism drops, the bat wakes up, warms up and tries to control Pd. the bat falls asleep again and the fungus takes over
this cycle repeats and bats die of exhaustion trying to fight Pd

Question 2

how is bats dying an issue for the environment and the food industry?

Answer 2

more than 300 fruit trees depend on bats for pollinisation
also an issue for insect population control
without bats to control the insects, farmers turn to more pesticides, which leads to more dangers for us

Question 3

what does monoculture mean?

Answer 3

herbs produce fruit without the need for fertilization: no sexual reproduction, no genetic diversity

Question 4

how did monoculture affect bananas?

Answer 4

the “big mike” banana variety, native to south asia, was planted in martinique by french colonizers
from there, those bananas were planted everywhere cause they were yummy
they started being decimated by fungal disease (fusariam wilt and its agent TR1)
this fungus is an ascomyota, the most recent, septated

Question 5

how did TR1 spread to kill that banana variety all over the world?

Answer 5

the spores penetrate the roots and go into the xylem vessels
this leads to a collapsed xylem and there is no more water that gets to the different parts of the plant
asexual spores are formed on dead plant tissue and they remain in the soil to infect another root

Question 6

what happened to the banana variety after big mike?

Answer 6

cavendish was introduced, another monoculture, planted everywhere around the world
history repeats with fusarium oxysporum TR4

Question 7

why can you not treat those plants with antifungals?

Answer 7

these fungi will develop resistant, this can also kill us

Question 8

what is another example of monoculture with Puccinia graminis?

Answer 8

a basidiomycota fungus
over the summer puccinia goes on wheat (asexual reproduction) and makes it look rusty
over the winter (sexual reproduction) it goes on barberry plants
in the UK, barberry was gotten rid of, and new wheat was bred and antifungals were added
but, insects (barberry carpet, a moth) relied on barberry plant for survival
therefore barberry was replanted in the UK
wheat stem rust is also coming back

Question 9

what is the mycorrhizal fungi?

Answer 9

symbiotic relationship between plants and fungi
symbiosis of 450 million years
80% of plants have this relationship
the fungus is mainly Glomeromycotina (zygomycetous)
the fungus can cover a lot more ground than the roots, extends surface area to acquire nutrients (with the hyphae)

Question 10

what are the 4 types of mycorrhizal interactions?

Answer 10

arbuscular
ectomycorrhizal
orchid
ericoid
the first two are the main ones

Question 11

how do the two main mycorrhizal fungi interactions work?

Answer 11

arbuscular:
arbuscular mycorrhizae fungi (AMG)
creates an arbuscule inside the cells
ectomycorrhizae:
on the roots, extends and increases surface area

Question 12

what do both parties contribute out of this symbiotic relationship?

Answer 12

fungi improve water and mineral assimilation (N, P from fertilizers)
without the fungus the plants have trouble absorbing the Nitrates and phosphates from the fertilizers, so it improves growth
plants provide the carbon to the fungi (carbs, lipids), also a good way to trap the Co2

Question 13

how do mycorrhizal fungi improve soil quality?

Answer 13

fungi secrete glomalin, a hydrophobic glycoprotein
this creates microaggregates in the soil and water flows better
this improves:
soil structure
carbon sequestration
water flow and availability
biodiversity
heavy metal absorption

Question 14

how do mycorrhizal fungi improve immunity?

Answer 14

they stimulate the health and metabolic activity of the plant to preserve against the presence of pathogens
stimulates the plant’s defence system: induced systemic resistance (ISR)
when a pathogen attacks the plant will be ready for it

Question 15

what is the grey mold that we see on fruit, and what is the good and bad of it?

Answer 15

Botrytis cinerea, the grey mold (ascomycota-leotiomycetes)
leads to 10 billion dollars in yearly crop loss
but it is used to make wine

Question 16

how is botrytis used to make wine?

Answer 16

creates the wine sauternes
the fungus land on the skin cells of the grape, creates an appressorium (infective structure)
the hyphae grow and penetrate, kill the skin cells
this infection weakens the skin of the grapes which allow for water evaporation and higher sugar concentration, making a sweeter wine
those grapes are handpicked to make sure that it’s only that specific fungus

Question 17

what are the 3 grape varieties?

Answer 17

semillion: main grapes used with thin skin
sauvignon blanc: bring acidity
muscadelle: grapes with floral note easily infected by fungus

Question 18

how is fungus used in cheese production?

Answer 18

Penicilium roqueforti (ascomycota)
the blue comes from the spores, asexual reproduction
critical for cheese maturation, gives smell and favour
proteolysis of dairy products and lipids secretes flavorful metabolites

Question 19

how were different strains of the fungus combined?

Answer 19

they discovered the necessary conditions for sexual reproduction
the different strands can now be combined to make new types of cheeses