本實驗利用BBTV病毒核酸純化改進法快速而大量獲得雙股及單股的病毒核
酸來從事實驗 。雙股的核酸大小約1.1Kb，與BBTV病毒顆粒核酸產生很強
的雜配反應，顯示其和病毒核酸有很強的同源性（homology）。電子顯微
鏡觀察的結果， 顯示單股和雙股病毒DNA都有線狀及系病毒基因體可重合
而成為一環形結構，總長1094b。此與 Dale（1993） 最近發表 BBTV之一
核酸片段序列同源性低，認定為BBTV之另一新核酸片段。但上述BBTV兩片
段和類似病毒Coconut foliar decay virus及 geminivirus都有一
stem- loop的構造而 loop部分的序列極序列間同源性低。將BBTV病毒核
酸DNA補成雙股，再加以選殖，而得到許多篩選株。其中有一篩選株其序
列與Dale所發表之BBTV病毒核酸片段之一的序列相同。但仍有多段篩選株
其序列與上述兩種BBTV核酸片段之序列皆不相同， 推測為第三種以外之
核酸片段。根據結果推論 BBTV 病毒的基因體是由許多不同的核酸片段所
組成。

Large quantity of double and single-stranded（ds and ss）
viral DNAs have been purified by using an improved purification
method .Compared with viral genome（ss DNA） and hybridization
analysis ,it is proved that the ss DNA is the viral DNAs
contain both linear and circular form. Two ds viral DNAs
have been cloned. Sequencing analysis of the ds DNA clones
revealed that the viral ds DNA is circular with a size of 1094
bp. The sequence is part- ialy homologous to the genome of
coconut foliar decay virus 1990）and the genome of BBTV
published by Dale（1993）,but both sequence homology are not
significant.Several ss viral DNAs were also cloned. DNA
hybridization tests revealed that there were several forms
of viral genome with different degrees of sequence
homology. I conclude from these results that BBTV is a new
group of circular ss DNA virus, the ds DNA may be the
replication intermediate of viral genome ,and the virus
contains at least 3 DNA components.51