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Genetic diversity, aggressiveness and metalaxyl sensitivity of Pythium spinosum infecting cucumber in Oman

Al-Sa'di, A.M. and Drenth, A. and Deadman, M.L. and De Cock, A.W.A.M. and Al-Said, F.A. and Aitken, E.A.B. (2008) Genetic diversity, aggressiveness and metalaxyl sensitivity of Pythium spinosum infecting cucumber in Oman. Journal of Phytopathology, 156 (1). pp. 29-35.

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Publisher URL: http://www3.interscience.wiley.com/cgi-bin/home

Abstract

A total of 24 isolates of Pythium spinosum from cucumber obtained from five regions in Oman were characterized for genetic diversity using amplified fragment length polymorphism (AFLP) fingerprinting and three isolates from the Netherlands, South Africa and Japan were included for comparison. Isolates from Oman were also characterized for aggressiveness on cucumber seedlings and sensitivity to metalaxyl. Identity of all isolates was confirmed using sequences of the internal transcribed spacer (ITS) region of the ribosomal DNA (rDNA), which showed more than 99% nucleotide similarity among all isolates. Using six primer-pair combinations, AFLP fingerprinting resolved 295 AFLP markers of which 193 were polymorphic among isolates from other countries and only six were polymorphic among isolates of P. spinosum from Oman. Seven different AFLP phenotypes of P. spinosum were recovered in Oman; two of them were found to contain over 79% of isolates and one was recovered from all regions in Oman. Phenotypes from Oman showed very high (?99%) levels of genetic similarity to each other compared to moderate (mean =53%) levels of genetic similarity with phenotypes from other countries. In addition, all isolates from Oman were found to be highly sensitive to metalaxyl and all were aggressive on cucumber seedlings at 25°C. The high genetic similarity among phenotypes of P. spinosum in Oman as well as recovering two major clones across regions may suggest that P. spinosum has been recently introduced in Oman via a common source.

Item Type:Article
Additional Information:© Blackwell Verlag.
Keywords:AFLP fingerprinting; damping-off; Oomycetes; parsimony analysis; phenotype.
Subjects:Science > Botany > Cryptogams
Plant pests and diseases > Individual or types of plants or trees
Science > Biology > Genetics
Plant culture > Vegetables
Deposited On:17 Nov 2008 06:39
Last Modified:31 Mar 2011 03:30

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