Enhancing identification accuracy for powdery mildews using previously underexploited DNA loci
Resource type
Journal article
Date published
August 26, 2019
Abstract
The internal transcribed spacer (ITS) DNA marker is routinely used for fungal identification but gives a clear result for only three out of four powdery mildew samples. A search for new markers indicates that some genes offer enhanced identification in comparison with ITS. Others fail due to amplification and sequencing difficulties and lack of informative variability. Powdery mildews (Ascomycota, Erysiphales) are biotrophic, fungal plant pathogens that commonly occur worldwide on a wide range of host plants. They are unsightly and greatly reduce the vigor of their hosts and have major impacts on crop and other cultivated plants. Species within this order are straightforward to spot, but difficult to identify. A citizen science scheme was run in 2013–2016 in the UK to gather a wide array of samples on which identification methods could be developed. Current techniques for identification and phylogenetic reconstruction show scope for improvement. In this paper, we review genes used in other fungal groups for discrimination at species level. Working protocols for amplification and sequencing of seven genes (actin, β-tubulin, calmodulin,Chs, elongation factor 1-α [EF1-α], Mcm7, and Tsr1) are developed with varying success; Mcm7 proves to be the most useful at differentiation between closely related, phylogenetically young powdery mildew species for phylogenetic reconstruction when used separately and in tandem with ITS. We therefore propose this as the most appropriate candidate gene to be used commonly in powdery mildew diagnostics alongside the ITS; furthermore, this could be transferred to similarly troublesome fungal clades.
Journal title
Mycologia
Publisher
Informa UK Limited
ISSN
0027-5514
eISSN
1557-2536
Rights statement
In Copyright