Tilletia indica - The Food and Environment Research Agency - Defra

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SECTION 1: INTRODUCTION Principle Hosts Tilletia indica causes the disease Karnal bunt, or partial bunt, of wheat (Triticum spp.). Triticale (X Triticosecale) is also naturally infected and rye (Secale) is a potential host. T. indica was added to the EC Plant Health Directive 77/93/EEC (now 2000/29/EC) as a I/AI pest in 1996 and quarantine requirements applied to seed and grain of Triticum, Secale and X Triticosecale from countries where T. indica is known to occur. Symptoms T. indica is a floret-infecting fungal smut pathogen. Unlike systemic smuts, not all the seeds on an ear are usually infected and the seeds are typically only partially bunted. Seeds are infected through the germinal end of the grain and the fungus develops within the pericarp where it produces a powdery, brownish-black mass of teliospores. When fresh, the spore masses produce a foetid, decaying fish-like smell (trimethylamine). Seeds are usually only partially colonised, showing various degrees of infection. Point infections are most common, but infection may also spread down the adaxial groove and, in severe cases, the whole grain may appear bunted (Figure 1.1). Figure 1.1. Grain infected with Tilletia indica (Karnal bunt). Symptoms range from partial bunting (point infections and infections spreading down the adaxial groove) to almost complete bunting. Photograph courtesy of G. L. Peterson, USDA.
SECTION II: DIAGNOSTIC SCHEME Scope of the Diagnostic Scheme The scheme for Tilletia indica describes procedures for: (i) detection of teliospores in imported seed or grain of wheat by a size-selective sieving wash test; (ii) morphological identification of teliospores detected in wash tests; (iii) isolation and germination of teliospores for molecular confirmation; (iv) molecular confirmation of cultures. 7
Page 1 and 2: EU RECOMMENDED PROTOCOL FOR THE DIA
Page 3 and 4: SECTION IV: REFERENCES ** 3
Page 5: LIST OF FIGURES Figure 1.1. Grain i
Page 9 and 10: Sampling Seed lots should be sample
Page 11 and 12: median profiles can be enhanced by
Page 13 and 14: Figure 2.2. Teliospores of Tilletia
Page 15 and 16: Figure 2.4. Teliospores of Tilletia
Page 17 and 18: 7 days 10 days 14 days T. horrida T
Page 19 and 20: conform to one specific species (si
Page 21 and 22: SECTION III. PROTOCOLS A1. Protocol
Page 23 and 24: 25. Finally, bleach all equipment u
Page 25 and 26: Figure 3.6. Tilletia indica teliosp
Page 27 and 28: A2. Protocol for extracting teliosp
Page 29 and 30: Teliospore Size (µm) Colour Orname
Page 31 and 32: Sample d (✔ boxes) T. horrida T.
Page 33 and 34: C. Protocol for isolation and germi
Page 35 and 36: Materials Aspirator bottle with dis
Page 37 and 38: SECTION IV: REFERENCES Aggarwal, R,

Tilletia indica - The Food and Environment Research Agency - Defra

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