Gene polymorphisms CVPDr on some plants citrus in Bali Island

Citrus Vein Phloem Degeneration (CVPD) is the main disease of citrus plants in Indonesia. This disease is caused by Gram negative bacteria, Candidatus Liberibacter asiaticus. Almost all citrus plants are susceptible to this disease and only a few citrus plants such as seedless lime (Citrus aurantiifolia var. Seedles) and kinkit citrus (Triphacia trifoliate) are tolerant. Both of these citrus plants store DNA fragments of CVPDr which are considered as tolerant factors (841 bp). However, this study found that CVPDr DNA fragments were also found in citrus plants susceptible to CVPD disease. This research aims to study DNA polymorphisms from CVPDr DNA fragments in citrus plants on the island of Bali. The PCR test showed T. trifoliate and C. aurantifolia that are resistant to CVPD and Pylogenically are in the same group as C. nobilis var Buleleng, C. reticulate var. Slayer Buleleng, and C. amblicarpa. On the other hand, citrus plants susceptible to CVPD are in a diff erent group. There are two types of citrus plants not containing CVPDr DNA fragments, namely C. nobilis var. Petang and M. paniculata L. These results indicate that the CVPDr DNA fragment polymorphism is a factor tolerant to CVPD disease.