Ustilago tritici is a fungus that causes loose smut of wheat. It is seed-borne and infects wheat seeds during germination. Symptoms appear as the inflorescence emerges, replacing spikelets with a black powdery mass of smut spores. The fungus has both a monokaryotic primary mycelium and a dikaryotic secondary mycelium. It reproduces through teliospores, which are thick-walled and pigmented spores produced on the dikaryotic mycelium that can contain one or two nuclei.

1. Kingdom fungi
USTILAGO TRITICI

2. Classification
Kingdom: Fungi
Phylum: Basidiomycota
Class: Ustilaginomycetes
Subclass: Ustilaginomycetidae
Order: Ustilaginales
Family: Ustilaginaceae
Genus: Ustilago
Species: U. tritici

3. Introduction
• It is also called as loose smut
of wheat
• seed borne systemic disease
• Causes heavy damages to
barley, rye , specially wheat
• Cool and moist
environments are most
suitable for the fungus
growth

4. Infection
• Embryo mode of
infection
• seed borne
• Active at time of
seed germination
• Very difficult to
identify effected
seed and healthy one

5. symptoms
• symptom appear on
emergence of inflorescence
• Deformed spikelet are
produced on plants
• soon the part of inflorescence
is replaced by smut spores and
black powdery mass
• Effected kernals emerge
slightly healthier one

6. smut spores

7. Plant body:
Mycelium
Primary mycelium:
1. It is monokaryotic , produced by germination of basidiospores
2. slender hyphae, hyaline, septate, each contain single haploid nucleus
3. They are short lived

8. Plant body:
Mycelium
Secondary mycelium:
1. It is dikaryotic , produced by pla7smogamy through 7se5xual reproduction
2. e5xtens7ive, septate, intercellular each contain binucleated
3. They are capable of infection

9. Mycelium
Primary mycelium secondary mycelium

10. Reproduction
Ustilago reproduces by
teliospores
They have follo4wing
characteristics
• Produced on dikaryotic
mycelium
• Made up of two layers
• Outer thick , pigmented ,
sometimes ornamental with
spines or reticulations
• At younger stage they are
binucleated but at maturity it
converted into diploid nucleus

11. From monokaryotic to dikaryotic

14. Loose smut of
wheat

15. Life cycle of
Ustilago tritici