plant diseases caused by fungi: basidiomycota

Plant Diseases Caused By Fungi: Basidiomycota

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Fungi

Kingdom Phylum Class

Fungi

(Higher)

Ascomycota Hemiascomycetes

Plectomycetes

Pyrenomycetes

Loculoascomycetes

Discomycetes

Deuteromycetes

Basidiomycota Teliomycetes

Hymenomycetes

Source: Ainsworth (1973)Note: Refer to Agrios (2005) for latest classification.


Basidiomycota

Club and mushroom fungi

Important characteristics:

Hyphae with dolipore septum

Produce rhizomorph

Sexual reproduction:

Hyphae produces clamp connections

Basidiospores in basidium (club-shaped)

Usually 4 basidiospores

Fruiting body: basidiocarp


Basidiomycota (cont’)

Hyphae with dolipore septum

Types of basidiospores

Formation of clamp connections

Source: Webster (1988)


Basidiomycota Classification

Class:

1. Teliomycetes

2. Hymenomycetes

(Ainsworth, 1973)

Order:

1. Ustilaginales (smut fungi)

2. Uredinales (rust fungi)

3. Exobasidiales

4. Ceratobasidiales

5. Agaricales (mushrooms)

6. Aphyllophorales

(Agrios, 2005)

7. Tulasnellales

(APS, 2000)


1. Order: Ustilaginales

Smut fungi ≈1,200 species Cause serious grain losses Most attack the kernels of grain crops Most produce only 2 kinds of spores:

Teliospores (non-infectious) Basidiospores (infectious)

Exist in many races Examples:

i. Ustilago maydisii. Ustilago scitaminae


1. Order: Ustilaginales (cont’)

i. Ustilago maydis Disease: Smut

Host: Corn

Symptom: Grains become swollen (hypertrophy) & replaced by the black smut spores

Source: Agrios (2005)


Ustilago maydis



1. Order: Ustilaginales (cont’)

ii. Ustilago scitaminae Disease: Smut

Host: Sugarcane

Symptom: Shoots look like a bundle of black strings

Source: Ong (2004)


2. Order: Uredinales

Rust fungi

≈ 5,000 species

Cause tremendous losses on grain crops, vegetables, field crops (cotton & soybean), ornamentals & trees (pine, apple & coffee)

Obligate parasites

Exist in special forms (formae specialis) Attack mostly leaves & stems

Infections usually appear as numerous rusty, orange & yellow spots


2. Order: Uredinales


Types of rust fungi:i. Microcyclic or short-cycled rusts: produce

only teliospores & basidiospores

ii. Macrocyclic or long-cycled rusts: produce spermatia, aeciospores, uredospores, teliospores & basidiospores Some macrocyclic rusts complete their life

cycles on a single host : autoecious

Others require 2 different or alternate hosts : heteroecious, e.g., Puccinia graminis (stem rust of wheat)

2. Order: Uredinales (cont’)


Puccinia graminis: Disease Cycle

Stage Reproduction structures Host

0 Haploid spermatium (produced in

spermagonium) + Receptive hyphae

Barberry

(2nd host)

I Aeciospores in aecium Barberry

II Uredospores in uredium Wheat

(1st host)

III Teliospores in telium Wheat

IV Basidiospores in basidium Wheat


Puccinia graminis



2. Order: Uredinales (cont’)

Rust diseases in Malaysia

i. Groundnut rust: Puccinia arachidis

ii. Corn rust: Puccinia polysora

iii. Long bean/French bean: Uromyces vignae

iv. Coffee rust: Hemileia vastatrix

Varieties Arabica & Liberica: susceptible

Variety Robusta: resistant

Puccinia polysora: Corn rust

Hemileia vastatrix: Coffee rust

Source: JPT


3. Exobasidiales

Lacking basidiocarp

Basidia produced on surface of parasitized tissue

Exobasidium vexans: Blister blight of tea

Source: JPT


4. Agaricales

Mushrooms: basidium without cross walls, produced on radiating gills or lamellae

Examples:

Lentinus edodes(Shiitake mushrooms)

Volvoriella volvaceae(“jerami padi” mushrooms)

Agaricus bisporus(Button mushrooms)

Source: http://insomniac.botany.uga.edu/1220/fungi1/fungi1.htm


Shiitake mushroomOyster mushroom

Button mushroom Lingzhi mushroom


Parasites

Examples:

i. Marasmiellus palmivorus

ii. Marasmiellus scandens

iii. Crinipellis perniciosa

4. Agaricales (cont’)



i. Marasmiellus palmivorus

Disease: Fruit bunch rot

Host: Oil palm

White soft basidiocarp

Marasmiellus palmivorus: Fruit bunch rot of oil palm (JPT).


• Marasmiellus scandens

Disease: White thread blight

Hosts: Cocoa, rubber, etc.

Marasmiellus scandens: White thread blight of cocoa (Dept. of Agriculture, Selangor).



iii. Crinipellis perniciosa Disease: Witches’-broom

Host: Cocoa

Confined to South America

Crinipellis perniciosa: Witches’-broom of cocoa (Agrios, 2005).



5. Aphyllophorales

Root & wood rot diseases

Origin of root & wood rots: forest trees

Spread mainly through: Direct contact with diseased roots

Spores

Examples: Rigidoporus lignosus Phellinus noxius Ganoderma boninense Corticium salmonicolor


– Rigidoporus lignosus Disease: White root

Hosts: Rubber, cocoa, tea, coffee, pepper, fruit trees

– Phellinus noxius Disease: Brown root

Hosts: Rubber, cocoa, oil palm

5. Aphyllophorales (cont’)

Rigidoporus lignosus: White root disease

Phellinus noxius: Brown root disease

Source: JPT



iii. Ganoderma boninense Disease: Basal stem rot

Host: Oil palm

Infects host through roots

Origin of disease: Coconut trees

Source: JPT



iv. Corticium salmonicolor

Disease: Pink disease

Hosts: Rubber, cocoa, fruit trees

Attacks branches

Lacking basidiocarp

Produces pink rhizomorph

Source: Rao (1975)


6. Tulasnellales

Oncobasidium theobromae Disease: Vascular-streak dieback (VSD)

Host: Cocoa

Symptoms: Dieback of shoots, brown streaking in vascular, characteristic yellowing in leaves

Serious in Asian region

Lacking basidiocarp

Spores infect young leaves

Symptoms can be observed 2-3 months after infection


Oncobasidium theobromae

Vascular-streak dieback (VSD) of cocoa. Source: JPT.


Oncobasidium theobromae


Thank You


Quiz

Q1 : Name the types of ascocarps

Q2 : Name the types of asexual fruiting body in Ascomycota

Q3 : Name the fungi (genus name) that causes Powdery mildew of cucurbits

Q4 : Why are deuteromycetes known as imperfect fungi?

Q5 : What is the typical symptom of a Cercospora sp. disease?


plant diseases caused by fungi: basidiomycota

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