Yang G, Che X, Gofman R, Ben-Shalom Y, Piestun D, Gafny R, Mawassi M, Bar-Joseph M
The S. Tolkowsky Laboratory, Department of Virology, Agricultural Research Organization, the Volcani Center, Bet Dagan, Israel.
Virus Genes. 1999;19(1):5-13. doi: 10.1023/a:1008105004407.
Citrus tristeza virus (CTV) strains were previously catalogued as seedling-yellows (SY) and non-SY (nSY) types, according to their yellowing and stunting effects on indicator seedlings. Among subisolates of the VT strain, which were selected from chronically infected Alemow plants, there was a correlation between the presence of 2.4-, 2.7- and 4.5-kb D-RNAs, and SY and nSY reactions, respectively. Similarly, plants infected with Mor-T subisolates, which cause SY, contained D-RNAs of 2.6 to 2.8 kb, while nSY subisolates from recovered sour orange tissue contained a major D-RNA of 5.1 kb. Plants harboring the 2.7-kb D-RNA were protected against challenge inoculation with a subisolate harboring the 4.5-kb D-RNA. This study suggests that the nSY reaction results either from the absence of SY gene(s) in the genomes of certain CTV strains or through the suppression of the effects of SY gene(s) by D-RNAs with 5' parts larger than 4000nt.
柑橘衰退病毒（CTV）毒株先前根据其对指示性幼苗的黄化和矮化效应被分类为幼苗黄化（SY）型和非幼苗黄化（nSY）型。在从长期感染阿蕾檬植株中挑选出的VT毒株的亚分离物中，2.4kb、2.7kb和4.5kb的D-RNA的存在分别与SY和nSY反应存在相关性。同样，感染导致SY的Mor-T亚分离物的植株含有2.6至2.8kb的D-RNA，而从恢复的酸橙组织中分离出的nSY亚分离物含有一条主要的5.1kb的D-RNA。携带2.7kb D-RNA的植株可免受携带4.5kb D-RNA的亚分离物的挑战接种。这项研究表明，nSY反应要么是由于某些CTV毒株基因组中不存在SY基因，要么是由于5'端大于4000nt的D-RNA抑制了SY基因的效应。
