甜瓜黄斑病毒三亚分离物S RNA的分子特征

 甜瓜黄斑病毒（Melon yellow spot virus, MYSV）首次发生于日本，造成甜瓜和黄瓜的严重损失，Kato等系统地研究了病毒的传播方式、寄主范围、超微结构和基因组特征，认为MYSV应为番茄斑萎病毒属（Tospovirus）的1个新种［1,2］。2006年以来，台湾的西瓜［3］和黄瓜［4］上相继发现MYSV。2009年春季，古勤生在海南三亚的保护地甜瓜上发现一种新发生的病毒病，发病率30%~100%，病株出现系统性黄化坏死斑点，为MYSV侵染的典型症状，结合分子检测结果判定病原为MYSV。

Molecular characterization of S RNA of a Melon yellow spot virus isolate in Sanya

The complete nucleotide sequence of S RNA of MYSV Sanya isolate (MYSV-SY) contains 3 257 nts and has two ORFs separated by an A-U-rich IGR of 872 nts, and 5′- and 3′- noncoding regions consist of 68 nts and 67 nts, respectively. Phylogenetic analysis with other completely sequenced MYSV isolates showed that MYSV-SY was most closely related to the isolate Phm from Physalis minima, with 97.0% nt identity in the genomic RNA sequence, and a distant relationship to isolates Tospo-melo (95.3%) and TW (94.9%). The ORF (nt 3190-2351) on the viral complementary strand encoded N protein of 279 aa with a molecular mass of 31.0 kDa. The N protein shared 97.5%-99.6% identities with those of other MYSV isolates. The other ORF (nt 69-1478) on the viral strand encoded NSs protein of 469 aa with a predicted molecular mass of 53.1 kDa. The NSs protein shared relatively higher identities (95.9%-98.1%) with those of other isolates. The comparison results of N and NSs proteins with the corresponding sequences of other isolates revealed the closest relationship between MYSV-SY and the isolate Phm, in accordance with that of genomic RNA sequence.