The Development and Deployment of Rapid In-Field Phytoplasma Diagnostics Exploiting Isothermal Amplification DNA Detection Systems

Abstract

Detection and diagnosis of phytoplasmas is an important requirement, both for the identification of their hosts, alternate hosts and potential insect vector species and for the management of these devastating diseases of plants. Being able to detect pathogen presence at pre-symptomatic stages allows the removal of infected plants before they provide a significant reservoir of the pathogen for spread of disease to other plants or dissemination via propagation material, whilst detection in weeds from which the disease might spread into crops allows appropriate weed control to be undertaken. Similarly, detection in potential insect vectors allows for management practices to be considered that might reduce the spread of the diseases. As new technologies have developed over the years since phytoplasmas were first discovered, the methods for detection have evolved, as have their sensitivity, reliability and ease of use. In-field or point-of-care diagnostics, which allows tests to be conducted rapidly on site with minimal equipment and costs and which also allows easy and unambiguous interpretation of the results, is a goal that has driven the implementation of diagnostic techniques. This chapter will detail how, with the advent of isothermal DNA amplification methods, particularly loop-mediated isothermal amplification (LAMP) and recombinase polymerase amplification (RPA), this goal is now being attained.