Plant + Fungal Diversity

Why do we need plant scientists?

• food security

• green bioeconomy

• environmental stability

• healthier foods

Food security

There is set to be 9.7 billion people by 2050 so food production must increase by 60-110%

How does improving yields impact food security?

• improve the productivity of crops

  • conventional breeding - selecting for yield

  • improved agronomy

  • GM

How does reducing waste impact food security?

• global food loss = ½ of food produced

• due to:

  • poor storage conditions

  • pests + disease

  • household food waste

  • retail - shelf life, appearance

How does adaptation to climate change impact food security?

climate change will drastically affect crop production

• drought resistance

• flooding tolerance

• salt-resistance

How does pest/disease control impact food security?

40% of crop yield lost to pests/disease each year

Importance of healthier foods

• improves the nutritional value of food

• reduce micronutrient deficiencies

• e.g golden rice - fortified with beta-carotene which is a source of vitamin A

How does reducing fertiliser/pesticide use impact environmental sustainability?

• produced using fossil fuels

• phosphate reserves are running out

• causes eutrophication

• damages biodiversity

How does protecting biodiversity affect environmental sustainability?

• farming has a drastic effect on biodiversity

• plants are a key stone to all ecosystems

Green Bioeconomy = biofuels

plant-based replacement for fossil fuels

Green Bioeconomy - Bioproducts

• production of natural products

• engineered to produce vaccines/pharmaceuticals

Characteristics of plants

• growth is indeterminate

• morphologically different according to growth environment

• plasticity - cells can undifferentiate and redifferentiate = allows for propagation

What are monocots vs dicots?

flowering plants (angiosperms) are either monocots or dicots

cotyledon = leaf like structure formed in embryo

What is a monocot?

has one cotyledon

e.g grasses, palms, orchids

• greater biomass

• all major crops

• greatest species diversity

What is a dicot?

has two cotyledons

e.g. generally broad-leafed plants

What are the 2 methods of pollination?

wind pollination

• flowers structured for dispersal

• large quantities of pollen

• common in monocots

Animal pollination

• usually insects

• brightly coloured - attractive

• usually have a benefit for animal - nectar

Evolution of plants

1. non-vascular plants

2. vascular plants

3. pre-seed vascular plants - have xylem + phloem

4. seeds but no flowers

5. seeds + flowers

What are fungi?

NOT plants

NOT animals

Kingdom of their own - 5 million species

• made of fruit body + mycelium

What is Chitin?

the main component of fungi cell walls

chain formed from N-acetylglucosamine units

What is Ergosterol?

specific molecule found in fungi cell membranes

• target for antifungal drugs

• indicator of fungal presence in soil

What does mycelium consist of?

interconnecting tubes with rigid walls that contain cytoplasm (hyphae)

What is the role of hyphae?

• absorption of nutrients - large SA:V

• excrete extracellular enzymes to break down large molecules

What is the difference in mycelium of higher fungi?

the tubes are divided into compartments by septa

• allows differentiation of mycelium - can result in complex fruit bodies

How do mycelium grow?

• arise from a germinating spore

• apical (from tip) growth

• form tangential connections to form network

What do fungi feed on?

• they don’t contain chlorophyll so cant photosynthesise

• they use C fixed in organic materials

  • they have a vast array of enzymes to break down these compounds

What is saprotrophy?

obtaining nutrients from dead plant/animal tissue

What is necrotrophy?

obtaining nutrients by killing and using nutrients from before or during death

What is biotrophy?

obtaining nutrients from living tissues

• mutualistic = beneficial to both fungi + plant

• parasitic = harmful to plant

Roles of saprotrophs

• nutrient cycling

• nutrient translocation

• humus formation

• soil structure + stability

Types of wood decay

• stain

• brown rot

• white rot

• soft rot

Characteristics of brown rot

• cellulose + hemicellulose broken down/used by fungi

• lignin is not used

• hyphae produce enzymes

Characteristics of white rot

• uses all compounds including lignin

• can completely decompose wood to CO2 + H2O

Characteristics of soft rot

• cellulose + hemicellulose used

• lignin removal is slow

• occurs in moist environements

• decay is much slower + less extensive

What are mycorrhizas?

plants depend in fungi forming partnerships with roots to enhance nutrient and water absorption.