Morphological, pathogenicity and molecular studies of fusarium isolates from orchids
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Date
2007
Authors
Mohamad Zain, Nurhayati
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Abstract
A total of 32 Fusarium spp were isolated from Dendrobium (29 isolates) and
Oncidium (3 isolates) showing symptoms of root and stem rot. Another eight
isolates were obtained from Fusarium stock cultures of USM. Based on
morphological characteristics, the isolates were identified as F. oxysporum, F.
proliferatum and F. solani. Pathogenicity tests against F. oxysporum, F.
proliferatum and F. solani were conducted on healthy Dendrobium and the
results showed that the three Fusarium were pathogenic to Dendrobium. In
VCG analysis, nitrate-nonutilizing mutants were generated from all F.
proliferatum and F. oxysporum isolates on a medium amended with maximum
2.5% KClO3. Nit mutant was not generated by F. solani. Four and five
vegetative compatibility groups were identified from F. proliferatum and F.
oxysporum, respectively. For molecular analysis using RAPD and PCR-RFLP of
ITS1-5.8S-ITS2 regions, banding patterns generated were able to distinguish all
the three species causing root and stem rot on Dendrobium and Oncidium.
Based on UPGMA cluster analysis, all the three species were clustered in a
different clusters. Therefore, the present study showed that morphological
characteristics and molecular techniques of RAPD and PCR-RFLP of ITS1-
5.8S-ITS2 can be used to characterize Fusarium species from Dendrobium and
Oncidium orchids.
Description
Master
Keywords
Science biology , fusarium isolates , orchids