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BIOS-110 Fungal Lecture 3 - Fungal nutrition, growth and

• Describe the features of a typical mycelial and how this relates to what we know about how fungi grow • Outline the two ways in which cells divide • Define and describe how fungi obtain their nutrition • Describe how a is formed (structure and nutrition of the fairy ring ). • Outline the different functions of . • Outline the different dispersal mechanisms. Tip initiation and branching • Apical dominance occurs in hyphae • Several factors influence branching • Higher quality of → more branches → dense • Mycelial regulation – some evidence • Branch position, often behind septum – vesicle trapping?

Fungionline.org.uk/images/1intro/hyphae1.JPG Image from MAF slides

Image from MAF slides http://msue.anr.msu.edu/news/managemen t_of_soybean_white_mold Powdery on pea Mycelium of Mycelium and spores infecting beans

http://www.gettyimages.co.nz/detail/illustration/athletes-foot-fungus- stock-graphic/125744200 Hyphae of Athlete foot fungus ( pisi)

Germinating spore Colony forming

Hyphae – branching and growing Falloon et al. 1989. Can. J Bot 67: 3410-3416. Image: RE Falloon, PW Sutherland & IC Hallett

Image: RE Falloon, PW Sutherland & IC Hallett

Image: RE Falloon, PW Sutherland & IC Hallett Sporulation, chains of spores Upright branches in older part of colony Colony profile

1. Apical growth means that • Mycelium expands in diameter • Often circular or spherical shape • Limited only by From: Young persons guide to the Fungi Kendrick A • Outer edges of mycelium youngest and inner regions oldest

• The largest (by area) is a fungus – spp. (honey fungus) colony in a in • Diameter 8.9 km (890 hectares/2200 acres) • Total colony mass 605 tons • Estimated to be 2400 old 2. Outer hyphae grow towards fresh substrates – drives growth

3. Hyphal branches may fuse where they touch (anastomose)

Rhizoctonia solani hyphal From Modern , Deacon 4. In older regions of the mycelium, nutrients exhausted, so growth ceases; → Existing components used to produce spores → Hyphae die (autolysis)

Image E. Bourguignon LU http://djsgrowers.blogspot.co.nz/2013/01/what-is-difference-between-noble-rot.html cinerea lesion on rot of grape berries grape leaf

https://www.flickr.com/photos/essjay/164675851 http://www.mattersingray.com.au/h73rdr53s/staff_room/magazine s/images/ringworm.jpg Ring worm on scalp Basket fungus ( cibarium) Unicellular fungi • most common types • structure similar to hyphal compartment

Sacchromyces internal structure (from , Prescott )

http://www.rpi.edu/dept/chem-eng/Biotech-Environ/beer/yeast/yeast2.htm Growth by increase in number of individuals. Two ways:- • Each cell grows to maximum size, doubles all components, new wall divides cell through centre • Parent cell produces a small ‘knob’ on outside which grows until large enough to be independent – is ‘walled’ off. ppdictionary.com/fungi

N.B. High rate of multiplication 1 cell → 1 billion in 10 h

Dimorphic fungi https://www.broadinstitute.org/files/news From: Fungi, man and his environment, Cook RC /images/2011/schizo-fissionyeast-v2.jpg • These convert between mycelial and unicellular forms. Environment changes trigger it Nutrition Heterotrophic – preformed organic material 1. External • fungi grow into/next to food sources • hyphal tip secrete to OUTSIDE • degrade food into small soluble molecules 2. Adsorptive nutrition Breakdown product absorbed, often by cells in position 3-10 behind tip E

Enzymes 0

E E TIME 12h E E

E E TIME 24h E E

E E E E TIME 36h E Image Eirian Jones E E E Nutrition

3. Complex systems Enzymes ‘turned’ on & off in response to nutrient types

4. Excretion of wastes, etc. Causes ‘staling’ of medium Commonly seen fungal growths 1. Foliar e.g. Botrytis rot in grapes

http://djsgrowers.blogspot.co.nz/2013/01/what-is-difference-between-noble-rot.html Botrytis cinerea rot of grape berries 2. Ringworm in humans and • Symptoms – expanding, itchy, pink rings on skin • Centre of lesions are dry and scaly • Transmission - usually by dead skin cells on furniture etc. - rarely from animals

http://www.mattersingray.com.au/h73rdr53s/staff_room/magazines/i mages/ringworm.jpg https://i.ytimg.com/vi/G2U1CbMazQg/hqdefault.jpg 3. Fairy rings • Expanding rings of lush grass growth in and lawns

• Fungus grows in soil http://www.interhort.com/_images/_cms/Image /Fairy_Ring_400.jpg • At advancing front, it produces enzymes which degrade soil organic → nutrients products into soil → Absorbed by fungus & adjoining grass → Lush grass growth • Fungal front grows on • Behind, a starvation zone (water, nutrients efficient fungus) → grass dies also produces Hydrocyanic acid – toxic to grass roots • As old fungal hyphae break down, they release their components into the soil → grass recovers Fungal colony From: The Biology of Fungi, Ingold CT

Advancing edge of fungal colony

Dying rear of fungal colony http://www.cpbr.gov.au/fungi/images- Fungus grows 10-15 cm / misc/mycelium/mycelium2g.gif Fairy rings - oreades

http://www.lawnscience.co.uk/lawn-issues/fairy-rings/ http://www.k-state.edu/turf/images/problem-solver/off-color/dark/fairy- ring/fairy_ring.jpg

http://www.daviddarling.info/images/fairy_ring_in_field.jpg Fungal reproduction Fungi grow vegetatively (only hyphae) as long as nutrients available – Assimilative mode When food runs out, fungus switches to reproductive mode – produces spores. Outer edge of colony – fresh substrate (1) Centre, older regions of the mycelium (2) substrate nutrients exhausted 1 → growth ceases → Existing components used to 2 produce spores → Hyphae die (autolysis)

Image E. Bourguignon LU Fungal reproduction

1. Almost all fungi produce SPORES on special hyphal branches

From: The Biology of Fungi, Ingold CT 2) Most fungi produce both an ASEXUAL and a SEXUAL spore type 3) There is a great variety of forms in spores and spore-bearing structures – basis of classification (from , Agrios) Spore structure

1. Most spores have:- • Multilayered wall, often impregnated with and • with a low water content & high storage materials e.g. lipids, , • Little internal differentiation • Low metabolic rate BIOS-110 Lecture 3 - Fungal nutrition, growth and reproduction • Describe the features of a typical mycelial colony and how this relates to what we know about how fungi grow • Outline the two ways in which yeast cells divide • Define heterotrophic nutrition and describe how fungi obtain their nutrition • Describe how a fairy ring is formed (structure and nutrition of the fairy ring fungus). • Outline the different functions of spores. • Outline the different spore dispersal mechanisms.