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Analysis of
Kenyan isolates of Fusarium solani f. sp. phaseoli
from common bean using colony characteristics, pathogenicity
and microsatellite DNA
Agnes W.
Mwang’ombe1*, Pixley K. Kipsumbai1,
Ezekiel K. Kiprop2, Florence M. Olubayo1
and Joel W. Ochieng3,4
1Department
of Plant Science and Crop Protection, Faculty of
Agriculture, University of Nairobi, P.O Box 30197-00100,
Nairobi, Kenya.
2Department
of Biological Sciences, School of Science, Moi University,
P.O. Box 1125-30100, Eldoret, Kenya.
3Faculties
of Agriculture and Veterinary Medicine, University of
Nairobi, Kenya.
4Centre
for Plant Conservation Genetics, Southern Cross University,
P.O. Box 157 Lismore NSW, 2480 Australia.
*Corresponding author. Email:
mwangombe@kenyaweb.com. Tel: +254 20 2055126. Fax: +254
20 631255.
Accepted 24 January, 2008 |
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Fusarium solani
(Mart) f.sp. phaseoli (Burk) Synd. and Hans., is a
plant pathogenic fungus that causes root rot in garden bean
(Phaseolus vulgaris L.). To evaluate methods used in
classifying strains of this pathogen, 52 Fusarium solani
f.sp. phaseoli isolates from infected bean plants
grown on different farms in Taita hills of Coast province,
Kenya, were cultured and characterized using morphology,
pathogenicity and microsatellite DNA. All the isolates
showed high variability in aerial mycelial growth, mycelia
texture, pigmentation (mycelia colour) when cultured on
potato dextrose agar medium, and conidial measurements on
Spezieller
Nahrstoffarmer agar medium. Colonies were grouped
into luxuriant, moderately luxuriant and scanty on aerial
mycelial growth; fluffy and fibrous based on mycelial
texture; purple, pink and white based on mycelia colour; and
long, medium and short macroconidial length. All the
isolates were pathogenic on GLP-2 (Rosecoco), a susceptible
bean variety commonly grown in Kenya. DNA analysis showed
that the isolates carried a high genetic diversity (gene
diversity = 0.686; mean number of alleles = 9).
Neighbour-Joining phylogenetic clusters reconstructed using
microsatellite variation showed three major clusters.
However, the microsatellite groupings were independent of
the altitude, colony characteristics and virulence of the
isolates.
Key words:
Fusarium solani, phaseoli, fungus, microsatellite,
genetic diversity, Phaseolus vulgaris. |
