SYNERGISTIC EFFECTS OF MICROBIAL ANTAGONISTS AND ...

---- --primarily (Chand and Logan, 1983) and AG-4 was common in the field and wash~ghly virulent on a vanety of hosts Recently, Christopher et a1 (2004) havedeveloped a technique called rapld ~mmunochromatographic lateral flow devlce(LFD) uslng hybrrdoma technique which allowed the product~on of specrticmonoclonal antlbodies (MAbs) and enabled the development of immunodiagnosticassay that detect the activity of the growing mycelium of R. solani alone. Accordingto pathogenicity, cultural morphology and hyphal growth rate it is possible todistinguish three different cultural types within R, solani. Salazar etal. (2000) showedthe complete DNA sequence of the ribosomal internal transcribed spacer (rlTS)region of 28 isolates of R, solani AG 2-2 from the previously identified cultural types.R. solani differ in their rDNA ITS region which correlates with the difference in theirbiolog~cal properties (Boysen er a/.. 1996: Kuninaga et al., 1996; Salazar et a/., 1999).All the data available show that there is a completely conserved 5.8s region, but showvariation in both ITS regions, and this variation in size and nucleotide sequence isgreater in the isolates which are different by anastomosis, host range and otherbiological criteriaEpldemlolo~~Epidemiology of the pathogen is that it can survive in soil, within the diseasedhost material as sclerotia It can persist in soil for years, since so many plants are hostsfor this pathogen. Symptoms on the plants vary from reddish-brown to bmwn spots,which can be sunken and can expand to kill the host plant These rots inhibit growthand cause stunting and poor vigour. Callus formation and thickening of the cell alsooccur. Leaves are covered with fungal threads. Being a pathogen of great diversitywith wide host range and lack of sharp differentiation among its specialized strains,R. solani finds great difficulty to develop resistance in crop varieties. Some of the