Bezerra-Agasie I C, Ferreira G B, de Ávila A C, Inoue-Nagata A K
Laboratório de Biologia Molecular, Embrapa Hortaliças, BR 060 km 09, C.P. 0218, CEP 70359-970, Brasília, DF, Brazil.
Plant Dis. 2006 Jan;90(1):114. doi: 10.1094/PD-90-0114C.
Three definitive and three tentative begomovirus species have been reported in tomato fields in Brazil according to a recent review (1). Extensive surveys have been conducted since the 1990s in solanaceous weeds and other crops planted close to tomato fields, but no tomato-infecting geminiviruses have been reported on those crops. During November 2003, leaves of one chili pepper plant "dedo-de-moça" (Capsicum baccatum var. pendulum) showing symptoms of yellow mosaic and leaf distortion were collected in Petrolina de Goiás (Goiás State). Serological analyses were carried out with polyclonal antisera produced in our laboratory against the following viruses: Potato virus Y (PVY), Pepper yellow mosaic virus (PepYMV), Tomato spotted wilt virus (TSWV), Tomato chlorotic spot virus (TCSV), Groundnut ringspot virus (GRSV), and Chrysanthemum stem necrosis virus (CSNV). Serological data showed that the plant was not infected with any of these viruses. A begomovirus-specific DNA-A fragment of 1.3 kb was amplified by polymerase chain reaction (PCR) from the analyzed plant. The fragment shared 98% identity to the partial coat protein coding region (CP), 94% to the intergenic region (IR), and 95% to the partial AC1 coding region of Tomato severe rugose virus (ToSRV) (GenBank Accession No. AY029750). Total DNA from the original infected plant was used to biolistically inoculate healthy plants of C. annuum and C. baccatum var. pendulum. Four resulting symptomatic plants, two from C. annuum and two from C. baccatum, were tested using PCR for begomovirus, and the nucleotide sequence of the amplified fragment confirmed they were infected with ToSRV. Whitefly inoculation of C. annuum, C. baccatum, and tomato was also performed, and all plants expressing symptoms were confirmed to be infected with ToSRV by sequencing a begomovirus-specific amplified fragment. Cloning of the complete DNA-A was achieved by using TempliPhi (Amersham Biosciences, Piscataway, NJ) amplification and digestion with a single cutting restriction endonuclease (2). Sequencing of several clones showed that the complete DNA-A (GenBank Accession No. DQ207749) was 97% identical to ToSRV, confirming the results of the previous PCR analysis. The deduced amino acid sequences showed identities of 97% to the CP, 95% to AC1, 96% to AC2, 96% to AC3, and 88% to AC4 of ToSRV. Although begomoviruses have not yet been causing any significant losses in chili pepper in Brazil, they may be of potential importance. Moreover, chili pepper, a plant commonly found in gardens throughout the country, may serve as an alternate host in tomato-producing areas. To our knowledge, this is the first report of a begomovirus infecting chili pepper in Brazil. References: (1) C. M. Fauquet et al. Arch. Virol. 148:405, 2003. (2). A. K. Inoue-Nagata et al. J Virol Methods 116:209, 2004.
根据最近的一项综述(1),巴西番茄田中已报道了三种确定的和三种暂定的双生病毒属病毒。自20世纪90年代以来,已对茄科杂草和番茄田附近种植的其他作物进行了广泛调查,但尚未在这些作物上报道过感染番茄的双生病毒。2003年11月,在戈亚斯州的彼得罗利纳采集了一株表现出黄色花叶和叶片扭曲症状的“dedo-de-moça”辣椒(辣椒属pendulum变种)的叶片。用我们实验室生产的针对以下病毒的多克隆抗血清进行了血清学分析:马铃薯Y病毒(PVY)、辣椒黄色花叶病毒(PepYMV)、番茄斑萎病毒(TSWV)、番茄褪绿斑病毒(TCSV)、花生环斑病毒(GRSV)和菊花茎坏死病毒(CSNV)。血清学数据表明该植株未感染这些病毒中的任何一种。通过聚合酶链反应(PCR)从分析的植株中扩增出一个1.3 kb的双生病毒特异性DNA-A片段。该片段与番茄严重皱缩病毒(ToSRV)(GenBank登录号AY029750)的部分衣壳蛋白编码区(CP)有98%的同一性,与基因间隔区(IR)有94%的同一性,与部分AC1编码区有95%的同一性。来自原始感染植株的总DNA用于基因枪接种辣椒和辣椒属pendulum变种的健康植株。对4株出现症状的植株(2株来自辣椒,2株来自辣椒属pendulum变种)进行了双生病毒的PCR检测,扩增片段的核苷酸序列证实它们感染了ToSRV。还对辣椒、辣椒属pendulum变种和番茄进行了烟粉虱接种,通过对双生病毒特异性扩增片段进行测序,确认所有表现出症状的植株都感染了ToSRV。通过使用TempliPhi(Amersham Biosciences,皮斯卡塔韦,新泽西州)扩增并用单一切割限制性内切酶进行消化,实现了完整DNA-A的克隆(2)。对几个克隆的测序表明,完整的DNA-A(GenBank登录号DQ207749)与ToSRV有97%的同一性,证实了先前PCR分析的结果。推导的氨基酸序列与ToSRV的CP有97%的同一性,与AC1有95%的同一性,与AC2有96%的同一性,与AC3有96%的同一性,与AC4有88%的同一性。尽管双生病毒尚未在巴西的辣椒上造成任何重大损失,但它们可能具有潜在的重要性。此外,辣椒是该国各地花园中常见的植物,可能在番茄产区作为替代寄主。据我们所知,这是巴西双生病毒感染辣椒的首次报道。参考文献:(1)C.M. Fauquet等人,《病毒学档案》148:405,2003年;(2)A.K. Inoue-Nagata等人,《病毒学方法杂志》116:209,2004年。