Komatsu Ken, Kagiwada Satoshi, Takahashi Shuichiro, Mori Takuma, Yamaji Yasuyuki, Hirata Hisae, Ozeki Johji, Yoshida Akiko, Suzuki Masashi, Ugaki Masashi, Namba Shigetou
Laboratory of Bioresource Technology, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba, Kashiwa, 277-8562, Japan.
Virus Genes. 2005 Aug;31(1):99-105. doi: 10.1007/s11262-005-2205-z.
To elucidate the genomic determinants of Potato virus X (PVX) strains, which cause diverse responses in host plants, we determined the complete genomic RNA sequences of four Japanese PVX strains: PVX-BS, -BH, -OG, and -TO. These four strains, plus the previously sequenced PVX-OS strain, differ in their pathogenicity in wild potato (Solanum demissum) and tobacco (Nicotiana tabacum cv. Samsun NN). The genomic sequences of these five PVX strains were highly homologous (i.e., the nucleotide sequence identity ranged from 95.4 to 98.5%). Phylogenetic analysis indicated that the Japanese PVX strains originated from an ancestral PVX strain in the European group, and that the virulence of these strains in both S. demissum and tobacco is not correlated with their phylogenetic relationships, suggesting that the pathogenicity of each strain in these host plants is determined by a relatively small number of nucleotides and can easily be altered independent of phylogenetic relationships. Particularly, OS, BH, and BS, which respectively produce markedly contrasting ringspot, mosaic, and asymptomatic infections in tobacco leaves, were the most closely related, suggesting that these three strains are an attractive model for analyzing the genetic determinants causing these symptoms. A possible correlation between the genomic and biological differences of these strains is discussed.
为阐明在寄主植物中引起不同反应的马铃薯X病毒（PVX）株系的基因组决定因素，我们测定了4个日本PVX株系：PVX-BS、-BH、-OG和-TO的完整基因组RNA序列。这4个株系，加上之前测序的PVX-OS株系，在野生马铃薯（Solanum demissum）和烟草（Nicotiana tabacum cv. Samsun NN）中的致病性有所不同。这5个PVX株系的基因组序列高度同源（即核苷酸序列同一性范围为95.4%至98.5%）。系统发育分析表明，日本PVX株系起源于欧洲组中的一个祖先PVX株系，并且这些株系在S. demissum和烟草中的毒力与其系统发育关系无关，这表明每个株系在这些寄主植物中的致病性由相对较少的核苷酸决定，并且可以独立于系统发育关系而容易地改变。特别是，分别在烟草叶片中产生明显不同的环斑、花叶和无症状感染的OS、BH和BS关系最为密切，这表明这三个株系是分析导致这些症状的遗传决定因素的一个有吸引力的模型。本文讨论了这些株系的基因组差异与生物学差异之间可能存在的相关性。
