Variation in the nrDNA ITS sequences of some powdery mildew species: do routine molecular identification procedures hide valuable information?

Kovacs, Gabor M. and Jankovics, Tunde and Kiss, Levente ORCID: (2011) Variation in the nrDNA ITS sequences of some powdery mildew species: do routine molecular identification procedures hide valuable information? European Journal of Plant Pathology, 131 (1). pp. 135-141. ISSN 0929-1873


During the past years, nrDNA ITS sequences have supported the identification of many powdery mildew fungi because comprehensive analyses showed that differences in these sequences have always correlated with the delimitation of different species and formae speciales of the Erysiphales. Published data, obtained using direct sequencing of the PCR products, suggested that even one to five nucleotide differences in the ITS sequences delimit different, albeit closely related, species, and/or indicate differences in host range patterns. Here we show that such differences in the ITS sequences can be detected even in a single sample of a powdery mildew fungus. We sequenced the ITS region in 17 samples, representing six powdery mildew species, both directly and after cloning the PCR products. Among these, samples of O. longipes exhibited two or three, samples of O. neolycopersici three or four, those of an Oidium sp. from Chelidonium majus up to seven, and a sample of another Oidium sp. from Passiflora caerulea two different ITS types determined after cloning. No ITS nucleotide polymorphisms were found in samples of O. lycopersici and Erysiphe aquilegiae. This suggests that some powdery mildew taxa are more variable at the ITS level than others. Thus, although the ITS sequences determined by direct sequencing represent robust data useful in delimitation and phylogenetic analysis of distinct species of the Erysiphales, these need to be used with precaution, and preferably determined after cloning, especially when dealing with closely related taxa at species and sub-species levels. With this method a hitherto undetected genetic diversity of powdery mildews can be revealed.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version due to publisher copyright policy. However, article can be freely accessed through the publisher's website at:*~hmac=78c5d6dfa25a4104161f0549e24fe9c6bf56d6a231726293b5f7189356db8e89
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 01 Jun 2017 00:01
Last Modified: 13 Jul 2021 04:13
Uncontrolled Keywords: Erysiphales; GenBank; ITS polymorphism; paralogue sequences; applied microbiology and biotechnology; molecular techniques; microbial diseases and parasites; plant pathology; fungal pathogens and diseases; plant science; biochemistry; molecular biology; plant/microbe interactions; plant science; plant pathology and symbioses; plant pathology; fungi - general; diseases;
Fields of Research (2008): 06 Biological Sciences > 0604 Genetics > 060408 Genomics
06 Biological Sciences > 0605 Microbiology > 060505 Mycology
Fields of Research (2020): 31 BIOLOGICAL SCIENCES > 3105 Genetics > 310509 Genomics
31 BIOLOGICAL SCIENCES > 3107 Microbiology > 310705 Mycology
Socio-Economic Objectives (2008): E Expanding Knowledge > 97 Expanding Knowledge > 970106 Expanding Knowledge in the Biological Sciences
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