Plant pathogenic bacteria, phytoplasmas, viruses and viroids cause harmful, widespread and economically important diseases in a very broad range of plant species worldwide. Damage is often sufficient to cause significant yield losses in cultivated plants. The two main effects on agriculture are decreased production and, in a less direct way, the need for the implementation of expensive management and control procedures and strategies.

The lack of suitable chemical control methods means that prevention is necessary to avoid the dissemination of the pathogens. Prevention measures require pathogen detection methods of high sensitivity, specificity and reliability, because many phytopathogenic bacteria and viruses can remain latent, in low numbers, or in special physiological states in propagative plant material and in other reservoirs. Accurate detection of phytopathogenic organisms is crucial for virtually all aspects of plant pathology, from basic research on the biology of pathogens to the control of the diseases they cause.

Rapid and accurate methods for detection and diagnosis of plant pathogens are required to apply treatments, undertake agronomic measures or proceed with eradication practices, particularly for quarantine pathogens. In recent years, there has been an exponential increase in the number of protocols based on nucleic-acid tools. Those based on PCR or Real-Time PCR are routinely used worldwide. However, nucleic acid extraction is still necessary in many cases and inhibition problems are decreasing the sensitivity of molecular detection. Integrated protocols that include the use of molecular techniques as screening methods, followed by confirmation by other techniques are advisable. Overall, molecular techniques based on different types of PCR amplification and especially on real-time PCR are leading to high throughput, faster and more accurate detection methods for the most severe plant pathogens, with important benefits for agriculture.

from Lopez et al in Curr. Issues Mol. Biol. (2009) 11: 13-46

Further reading:
Plant Pathogenic Bacteria: Genomics and Molecular Biology
Real-Time PCR: Current Technology and Applications
Real-Time PCR in Microbiology: From Diagnosis to Characterisation

Labels: bacteria, pathogen, PCR, plant, real-time PCR