Arabis mosaic virus(ArMV)had been found in the Gladiolus hybridus imported from the Netherlands by DAS-ELISA.Two pairs of primers were designed according to the conserved region of the coat protein(CP) gene sequence of Arabis mosaic virus(ArMV),and two amplified bands with expected sizes of 750 bp and 250 bp were obtained by reverse transcription polymerase chain reaction(RT-PCR).The sensitivity of nested PCR was higher than that of single RT-PCR.Analysis of the partial sequenced CP gene showed that the isolate was closed to ArMV with similarity of 99.0%-100%.All the results demonstrated that the isolated virus was ArMV.
Eight hundred twenty four nit mutants were induced from 73 strains of Fusarium oxysporum f.sp.vanillae,and classified into four phenotypes by their abilities to utilize different nitrogen sources.Among these mutants,64.9% were characterized as nit 1,24.3% as nit 3,9.8% as nit M,1.0% as nit X.Based on complementary pairing tests of different nit mutants on the medium MM,44 isolates belonged to 8 different VCGs,29 isolates were classified into single and different VCGs.These results indicated that there was signi-ficant VCG diversity in Fusarium oxysporum f.sp.vanillae population.VCGs might be correlated with geographic origin of strains,but no close correlation was found between VCGs and pathogenicity.
