甘蔗杆状病毒基因组片段整合入杂种甘蔗基因组的证据

Evidence of Sugarcane bacilliform virus DNA Fragment Integrated into the Saccharum Inter-Specific Hybrids Genome

为研究甘蔗杆状病毒Sugarcane bacilliform virus(SCBV)的基因组片段是否整合进杂种甘蔗Saccharuminter-spec ific hybrids基因组,以采自广西甘蔗研究所的1株杂种甘蔗植株叶片总DNA为模板,根据已报道的甘蔗杆状病毒基因组序列设计多条特异引物.经PCR扩增、产物克隆及序列分析,获得1个全长为5 364 bp的核苷酸序列.该序列具有SCBV基因组结构特征,含有2个完整的ORF,与GenBank中已报道的2个SCBV分离物之间的核苷酸及氨基酸序列同一性均大于70%,但该序列与完整的SCBV基因组全序列相比,不具备完全的ORF3,缺失了对病毒复制过程极为重要的功能性基因RNase H的序列区段.通过Southern-b lot杂交分析,初步推测其为一段整合入杂种甘蔗基因组中的SCBV基因组序列.

In order to investigate whether fragments of Sugarcane bacilliform virus （SCBV） were integrated into Saccharum inter-specific hybrids genome, a DNA fragment homologous to SCBV was ainplified from a hybrid sugarcane plant （Saccharum inter-specific hybrids var. ROC 25 ） grown in Sugarcane Re- search Center in Guangxi Province with SCBV-specific primers. The amplified fragments were cloned and sequenced. The sequence analysis revealed that this fragment contains 5364 nucleotides and shares over 70% similarity at both the nucleotide level and amino acid level with reported isolates of SCBV. The se- quence has two complete open reading frames （ORFs） , which resembles to SCBV ORF1 and ORF2 organizationally, but the open reading frame of RNase H （RH） was absent compared with SCBV. Based on Southern-blot analysis, the amplified sequence might be a SCBV genomic DNA fragment integrated into hybrid sugarcane genome.