Napier grass stunt and head smut diagnostics Yaima Arocha and John Lucas Presented at the ASARECA/ILRI Workshop on Mitigating the Impact of Napier Grass Smut and Stunt Diseases, Addis Ababa, June 2-3, 2010

NAPIER GRASS STUNT

Napier Head Smut Disease Napier smut (NHS) due to infection by Ustilago kamerunensis .

Ustilago cynodontis From smutted Cynodon , Ethiopia, 2007 Putative U. kamerunensis From Kenya, 2007 Cultural morphology 1

Mixture of budding and filamentous cells characteristic of smut fungus Cultural morphology 2 . Microscopic characters

Molecular Identification of Ustilago kamerunensis PCR amplifications from U. kamerunensis (2-4, 6-8, 10-12) and U. cynodontis (5, 9, 13) with primers targeting the  -tubulin gene (F1/R2, 2-5; and F2/R1, 10-13) and ITS region (ITS1/4, 6-9). Lanes 14-16. Positive controls group 16SrIII and 16SrXI (16). More data can be obtained from authors 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Hybridization signals from PCR products from Kenyan (UK) isolates with the  -tubulin probe.

NHS-infected Napier source plants (Kenya)

Uniformly smutted inflorescences of field-infected Napier plants

Distorted inflorescence

NG-1 month- post-inoculated plants

PCR amplicons from inoculated plants using  -tubulin primers U U cynodontis reference U. kamerunensis Plant Control samples

Draft diagnostic lab manual Edition 3