Jenner C E, Sánchez F, Nettleship S B, Foster G D, Ponz F, Walsh J A
Horticulture Research International, Wellesbourne, Warwick, UK.
Mol Plant Microbe Interact. 2000 Oct;13(10):1102-8. doi: 10.1094/MPMI.2000.13.10.1102.
The viral component of Turnip mosaic virus (TuMV) determining virulence to the Brassica napus TuRB01 dominant resistance allele has been identified. Sequence comparisons of an infectious cDNA clone of the UK 1 isolate of TuMV (avirulent on TuRB01) and a spontaneous mutant capable of infecting plants possessing TuRB01 suggested that a single nucleotide change in the cylindrical inclusion (CI) protein coding region (gene) of the virus was responsible for the altered phenotype. A second spontaneous mutation involved a different change in the CI gene. The construction of chimeric genomes and subsequent inoculations to plant lines segregating for TuRB01 confirmed the involvement of the CI gene in this interaction. Site-directed mutagenesis of the viral coat protein (CP) gene at the ninth nucleotide was carried out to investigate its interaction with TuRB01. The identity of this nucleotide in the CP gene did not affect the outcome of the viral infection. Both mutations identified in the CI gene caused amino acid changes in the C terminal third of the protein, outside any of the conserved sequences reported to be associated with helicase or cell-to-cell transport activities. This is the first example of a potyvirus CI gene acting as a determinant for a genotype-specific resistance interaction.
已鉴定出芜菁花叶病毒（TuMV）中决定对甘蓝型油菜TuRB01显性抗性等位基因毒力的病毒成分。对TuMV英国1分离株（对TuRB01无毒）的感染性cDNA克隆与能够感染具有TuRB01的植物的自发突变体进行序列比较，结果表明病毒圆柱状内含体（CI）蛋白编码区（基因）的单个核苷酸变化导致了表型改变。第二次自发突变涉及CI基因的不同变化。构建嵌合基因组并随后接种到对TuRB01进行分离的植物品系中，证实了CI基因参与了这种相互作用。对病毒外壳蛋白（CP）基因的第九个核苷酸进行定点诱变，以研究其与TuRB01的相互作用。CP基因中该核苷酸的身份不影响病毒感染的结果。在CI基因中鉴定出的两个突变均导致该蛋白C末端三分之一处的氨基酸变化，这些变化发生在任何据报道与解旋酶或细胞间运输活性相关的保守序列之外。这是马铃薯Y病毒CI基因作为基因型特异性抗性相互作用决定因素的首个实例。
