THE USE OF A DIGOXIGENIN-LABELED SYNTHETIC DNA OLIGONUCLEOTIDE FOR THE RAPID AND SENSITIVE IDENTIFICATION OF MELOIDOGYNE-INCOGNITA

Accurate identification of Meloidogyne species is essential for effect ive control and management strategies. Variable morphology and the exi stence of intraspecific races make most current diagnostic procedures difficult and unreliable. This work describes the use of a 30 base non -radioactive digoxigenin-labelled synthetic oligonucleotide to identif y M. incognita in Slot Blot assays. The sensitivity of this approach i s such that it is capable of detecting as little as 2 ng of M. incogni ta genomic DNA. Preliminary attempts to characterise the 50 base M. in cognita specific probe on which this oligonucleotide was based indicat ed that it could represent approximately 1 % of the haploid genome of M. incognita and is repeated 17 000 times.