Improving disease diagnostic methods for various plant pathogens in the Plant Molecular Diagnostic Lab

Summary

Plant pathogens affect the multibillion-dollar agriculture industry in GA every year. Early and quick detection of plant pathogens will be the first and most important step in the management of plant diseases. There are several detection methods such as traditional microscopy, morphology (sign and symptom based), polymerase chain reaction (PCR), and serological ELISA (enzyme-linked immunosorbent assay) for diagnosis of plant pathogens; however, these methods are time-consuming, less sensitive for plant samples at early infection stages that harbor relatively low pathogen populations. Therefore, it is important to have early, economical, and accurate disease diagnostic tools to optimize disease management. The Plant Molecular Diagnostic Lab (MDL) developed novel advanced diagnosis techniques for various plant pathogens across a range of crops.

Situation

Management of plant diseases is always challenging. Many plant pathogens are difficult to culture and the diseases they cause can look like other common problems which result in inappropriate fungicide applications. Microscopy is the standard tool in disease diagnosis and in many cases the only tool available, requiring highly trained personnel and taking more time than molecular methods. While some plant pathogens can be identified with traditional polymerase chain reaction (PCR), this method is less sensitive and requires access to sophisticated and bulky laboratory equipment. In particular, the complexity of the thermal cycling equipment required for PCR restricts the use of this method to well-equipped laboratories.

Response

For rapid and accurate diagnosis, the Plant Molecular Diagnostic Lab (MDL) has developed cost-efficient advanced loop-mediated isothermal amplification assays (LAMP) for multiple plant pathogens which have the potential to overcome many of the limitations of traditional diagnostic assays. During 2020, MDL developed advanced LAMP techniques for specific and rapid detection of two important vegetable pathogens (cucurbit leaf crumple virus and Phytophthora capsici) and a pecan root-knot nematode, Meloidogyne partityla, under laboratory and field conditions. The sensitivity of the LAMP assays was 10 to 100 times higher than regular PCR and testing was carried out rapidly (30 min-1 hr) with minimal equipment (a water bath or isothermal heat block).

Impact

Development of the rapid detection techniques facilitates quicker response to disease outbreaks and therefore reduces chemical control costs for growers and agricultural industries. Moreover, this portable rapid detection technique can be used for routine diagnostics, surveillance, biosecurity, and epidemiology studies. This information will be very helpful to increase awareness about emerging disease spread for growers, researchers, and extension specialists in Georgia.

State Issue

Plant Production

Details

• Year: 2020
• Geographic Scope: National
• County: Tift
• Location: Coastal Plain Station, Tifton
• Program Areas:
  • Agriculture & Natural Resources