High variation in repetitive DNA fragment length for white spot syndrome virus (WSSV) isolates in Thailand

Diseases of Aquatic Organisms

Paranee Pungchai¹  Chainarong Wongteerasupaya¹  Sakol Panyim¹  T. W. Flegel¹  Boonsirm Withyachumnarnkul¹  Peter J. Walker¹  Vichai Boonsaeng¹ 

关键词: WSSV;    DNA sequence variation;    Tandem DNA repeat;   

DOI  :  10.3354/dao054253

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: White spot syndrome virus (WSSV) presently causes the most serious losses to shrimp farmers worldwide. Earlier reports of high DNA sequence homology among isolates from widely separated geographical regions suggested that a single virus was thecause. However, we have found surprisingly high variation in the number of 54 bp DNA repeats in ORF94 (GenBank AF369029) from 55 shrimp ponds (65 shrimp samples) experiencing WSSV outbreaks in Thailand in 2000 and 2002. These were detected by PCRamplification using primers ORF94-F and ORF94-R flanking the repeat region. Altogether, 12 different repeat groups were found (from 6 to 20 repeats) with 8 repeats being most frequent (about 32%). Extracts prepared from individual shrimp in the sameoutbreak pond belonged to the same repeat group while those collected at the same time from separate WSSV outbreak ponds, or from the same ponds at different times, usually belonged to different repeat groups. This suggested that different outbreaks werecaused by different WSSV isolates. In contrast to the highly variable numbers of repeats, sequence variation within the repeat region was confined to either T or G at Position 36. These variations may be useful for epidemiological studies on the local andglobal movement of WSSV, since there is high variation in the number of repeats (good for local studies) but little sequence change (good for global studies).

【 授权许可】

Unknown