The development of cheap diagnostic techniques could assist decision-making in relation to pest and disease management. The development of diagnostic kits using antibodies, such as Enzyme Linked ImmunoSorbent Assay (ELISA), and other molecular assays, can enable the precise identification of viruses, bacteria and other disease-causing agents, and is now an established tool in disease management in many farming systems. Diagnostic assays have also been developed to identify a wide range of other organisms, chemicals (such as undesirable by-products, e.g. aflatoxin), or impurities involved with food quality.
|
DNA diagnostics are also a powerful technique for identification of pathogens and other organisms in agriculture. Most DNA diagnostics are now based on the use of the polymerase chain reaction (PCR), a common research tool used in most molecular biology laboratories worldwide, which can be used to specifically amplify segments of DNA. Most PCR techniques require the use of the enzyme Taq polymerase which until recently was protected by patents requiring that any commercial use of the PCR technique would have to pay royalties to the holders of the Taq polymerase patent. The enzyme Taq polymerase is now in the process of becoming a ‘generic' biochemical reagent which will substantially reduce the cost of PCR applications in research and commerce.
Examples from FAO-BioDeC: All ELISA-related work is reported to be in the experimental phase, with Morocco working on potato and sugar cane, Tunisia on grapevine and Egypt on detection of ZYMV in cucurbits. The use of ELISA for cassava diagnostics is under study in Malawi, Nigeria, Uganda and Zimbabwe, for cowpea in Cameroon and Nigeria, and maize in South Africa and Zimbabwe.
At present, most of the reported work on PCR diagnostics is in the experimental phase. Egypt is working on PCR analysis of ZYMV in cucurbits and TYLCV in tomato. Maize disease diagnostics is the subject of PCR studies in South Africa, Uganda and Zimbabwe, while diagnosis tools are studied for diseases of cowpea in Cameroon and Nigeria, cassava in South Africa and unspecified work is underway in Burkina Faso and Ghana. |
