Analisis variasi genetik Betanodavirus penyebab Viral Nervous Necrosis pada Kerapu berdasarkan sekuen gen protein selubung

SYAKURI, Hamdan, Dr. Rarastoeti Pratiwi, M.Sc

2007 | Tesis | S2 Bioteknologi

Betanodavirus mengakibatkan penyakit viral nervous necrosis (VNN) yang menjadi salah satu masalah utama budidaya ikan laut, termasuk kerapu. Penyakit ini menyebabkan mortalitas tinggi terutama pada fase larva dan yuwana. Virus tersebut berdasarkan sekuen gen protein selubung terbagi menjadi empat kluster genotipe, yaitu tiger puffer nervous necrosis virus (TPNNV), striped jack nervous necrosis virus (SJNNV), barfin flounder nervous necrosis virus (BFNNV), dan redspotted grouper nervous necrosis virus (RGNNV). Pengembangan vaksin dan metode deteksi membutuhkan informasi tentang variasi genetik tersebut. Tujuan penelitian ini adalah melakukan analisis variasi genetik betanodavirus isolat Indonesia berdasarkan sekuen gen protein selubung. Gen protein selubung dari enam isolat betanodavirus berhasil diamplifikasi, diklonasi dalam pBSKS dan disekuensing. Semua isolat betanodavirus pada penelitian ini termasuk dalam kluster RGNNV dan mempunyai similaritas 99% pada tingkat nukleotida serta 98-99% pada tingkat asam amino. Enam isolat tersebut mempunyai epitop sel T prediktif yang relatif sama.

Betanodavirus is a causative agent of viral nervous necrosis, which is one of main problems in finfish mariculture, including groupers. This disease has been associated with high mortalities especially in larvae and juvenile stages. According to the nucleotide sequence of coat protein gene, this virus can be classified into four genotypes, tiger puffer nervous necrosis virus (TPNNV), striped jack nervous necrosis virus(SJNNV), barfin flounder nervous necrosis virus (BFNNV), and redspotted grouper nervous necrosis virus (RGNNV). The development of vaccine and detection method require genetic variation data. The objective of this research is to analyze genetic variation of betanodavirus isolates from Indonesia based on coat protein gene sequence. Coat protein genes from six betanodavirus isolates were successfully cloned into pBSKS and sequenced. Result show that all isolates of this study are classified into RGNNV genotype and have 99% similarities at the nucleotide level and 98-99% similarities at the amino acid level. These isolates demonstrate a relatively identical predictive T cell epitopes.

Kata Kunci : Viral Nervous Necrosis,Variasi Genetik Betanodavirus, betanodavirus, viral nervous necrosis, genotype, coat protein gene, groupers