Characterization and Sap Transmission of Citrus Bent Leaf Viroid in Malaysia

A 328 nucleotide (nt) variant of Citrus bent leaf viroid (CBLVd) was characterized from citrus varieties in Malaysia showing leaf bending, stunting and midvein necrosis. CBLVd was detected by RT-PCR assay using CBLVd specific primers in 12 out of 90 samples, collected from six different areas in Malaysia. The viroid was present in five species of citrus namely Citrofortunella microcarpa, Citrus aurantifolia, C. hystrix, C. maxima and C. sinensis . Sequence analysis of the isolates obtained from this study showed 99-100% sequence identity to CBLVd Jp isolate (AB006734). Inoculation of sap obtained from a CBLVd positive C. aurantifolia , inoculated into six months old C. microcarpa seedlings showed the symptoms leaf bending, reduced leaf size of matured leaves and mild mosaic between 4 to 6 months after inoculation. The presence of CBLVd in the inoculated seedlings were confirmed by RT-PCR assay and sequencing. Author Summary The authors during a limited survey collected the citrus samples from citrus growing areas of Malaysia to detect the citrus viroids. Citrus viroids are associated with decline in citrus production. Thus, the presence of the citrus viroids and their spread needs to be investigated to facilitate the management of this pathogen in citrus orchards. The authors detected and characterized Citrus bent leaf viroid in Malaysian citrus.