Molecular diagnostics for fungal plant pathogens

Abstract

Accurate identification of fungal phytopathogens is essential for virtually all aspects of plant pathology, from fundamental research on the biology of pathogens to the control of the diseases they cause. Although molecular methods, such as polymerase chain reaction (PCR), are routinely used in the diagnosis of human diseases, they are not yet widely used to detect and identify plant pathogens. Here we review some of the diagnostic tools currently used for fungal plant pathogens and describe some novel applications. Technological advances in PCR-based methods, such as real-time PCR, allow fast, accurate detection and quantification of plant pathogens and are now being applied to practical problems. Molecular methods have been used to detect several pathogens simultaneously in wheat, and to study the development of fungicide resistance in wheat pathogens. Information resulting from such work could be used to improve disease control by allowing more rational decisions to be made about the choice and use of fungicides and resistant cultivars. Molecular methods have also been applied to the study of variation in plant pathogen populations, for example detection of different mating types or virulence types. PCR-based methods can provide new tools to monitor the exposure of a crop to pathogen inoculum that are more reliable and faster than conventional methods. This information can be used to improve disease control decision making. The development and application of molecular diagnostic methods in the future is discussed and we expect that new developments will increase the adoption of these new technologies for the diagnosis and study of plant disease.

Real-time PCR applied to study on plant pathogens: potential applications in diagnosis - a review

“…Real-time PCR can successfully quantify the initial specific target by the measurement of the amplification products. This occurs due to the accumulation of the PCR product with each cycle of amplification, and this is the reason why this method is called real-time PCR (McCartney et al 2003). Basically, there are two common methods for the detection of products in real-time PCR: first, non-specific fluorescent dyes that intercalate with any double-stranded DNA; and second, sequence-specific DNA probes consisting of oligonucleotides that are labelled with a fluorescent reporter which permits detection only after hybridisation of the probe with its complementary sequence.…”

A Review of Detection Methods for the Plant Viruses

“…The effective diagnostic methods of viruses, PCR is able to process by the specificity of the primers. PCR is proceeded through three steps, denaturation above 94 o C, annealing of primers at 50-75 o C (depend on primers) and elongation at 72 o C (Makkouk and Kumari, 2006;McCartney et al, 2003). RT-PCR used for the detection of RNA viruses requires reverse transcriptase which is added at the step of reverse transcription before the regular PCR step (Lopez et al, 2008;Webster et al, 2004).…”

“…The methods for detection and identification of viruses are critical in virus disease management (Aboul-Ata et al, 2011). Therefore, detection methods should be more convenient, effective, specific and permitted the use for detecting plant pathogens (McCartney et al, 2003).…”

Molecular Tools for Detection of Plant Pathogenic Fungi and Fungicide Resistance

“…Fingerprinting approaches allow the screening of random regions of the fungal genome for identifying species-specific sequences when conserved genes have not enough variation to successfully identify species (McCartney et al, 2003). Fingerprinting analyses are generally used to study the phylogenetic structure of fungal populations.…”