Impacts of Molecular Diagnostic Technologies on Plant Disease Management

Abstract

Detection and diagnosis of plant viruses has included serological laboratory tests since the 1960s. Relatively little work was done on serological detection of plant pathogenic bacteria and fungi prior to the development of ELISA and monoclonal antibody technologies. Most applications for laboratory-based tests were directed at virus detection with relatively little emphasis on fungal and bacterial pathogens, though there was some good work done with other groups of plant pathogens. With the advent of molecular biology and the ability to compare regions of genomic DNA representing conserved sequences, the development of laboratory tests increased at an amazing rate for all groups of plant pathogens. Comparison of ITS regions of bacteria, fungi, and nematodes has proven useful for taxonomic purposes. Sequencing of conserved genes has been used to develop PCR-based detection with varying levels of specificity for viruses, fungi, and bacteria. Combinations of ELISA and PCR technologies are used to improve sensitivity of detection and to avoid problems with inhibitors or PCR often found in plants. The application of these technologies in plant pathology has greatly improved our ability to detect plant pathogens and is increasing our understanding of, their ecology and epidemiology.

Cassava brown streak disease: a threat to food security in Africa

“…Effective diagnostics will help to monitor and forecast disease outbreaks, giving enough time for the application of management strategies (Martin et al, 2000;Miller et al, 2009). There are several methods available for detection and diagnosis of CBSD-causing viruses.…”

Development of a Nested Quantitative Real-Time PCR for DetectingPhytophthora cinnamomiinPersea americanaRootstocks

“…Most importantly, conventional PCR is not quantitative. In contrast quantitative real time PCR (qPCR) allows fast, reliable and accurate detection and quantification of plant pathogens (9,11). Sensitivity of qPCR can be greatly enhanced by implementing a nested approach in which a first round of amplification is carried out with conventional PCR and the J. Engelbrecht, 3, Plant Disease resulting product is then quantified in a second step by real time PCR.…”

“…With nested PCR two primer pairs are designed based on the sequence of a target gene, one of which is nested within the other. Specificity of real time and real time nested PCR can be assessed by gel electrophoresis, melting curves and by sequencing (11).…”

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

“…However, they still require further work to identify the PCR products when southern blot or sequencing are needed (Okubara et al 2005). Conventional PCR (cPCR) has emerged as a main tool for the diagnosis of plant pathogens and has contributed to reducing some problems related to the plant pathogens detection (Martin et al 2000). On the other hand, because of different testing parameters in cPCR assays, optimisation of conditions is very challenging and time consuming (Espy et al 2006).…”