Centre for Biological Control, Department of Zoology and Entomology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa; Citrus Research International, P.O. Box 20285, Humewood, Port Elizabeth 6013 South Africa.
Department of Biochemistry and Microbiology, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa.
J Invertebr Pathol. 2018 Sep;157:90-99. doi: 10.1016/j.jip.2018.08.006. Epub 2018 Aug 11.
Cryptophlebia peltastica is an agricultural pest of litchis and macadamias in South Africa with phytosanitary status for certain markets. Current control methods rely on chemical, cultural and classical biological control. However, a microbial control option has not been developed. An Alphabaculovirus from C. peltastica was recovered from a laboratory reared colony and morphologically characterised by transmission electron microscopy (TEM). Analysis of occlusion bodies indicated a single NPV (SNPV) varying in size from 421 to 1263 nm. PCR amplification and sequencing of the polh gene region using universal primers followed by BLAST analysis revealed a 93% similarity to a partial polh gene sequence from Epinotia granitalis NPV. Further genetic characterisation involving single restriction endonuclease (REN) digestion of genomic DNA was carried out to generate profiles for comparison against other baculovirus species and potential new isolates of the same virus. The complete genome of the virus was sequenced, assembled and analysed for a more comprehensive genetic analysis. The genome was 115728 base pairs (bp) in length with a GC content of 37.2%. A total of 126 open reading frames (ORFs) were identified with minimal overlap and no preference in orientation. Bioassays were used to determine the virulence of the NPV against C. peltastica. The NPV was virulent against C. peltastica with an LC value of 6.46 × 10 OBs/ml and an LC value of 2.46 × 10 OBs/ml, and time mortality ranging between 76.32 h and 93.49 h. This is the first study to describe the isolation and genetic characterisation of a novel SNPV from C. peltastica, which has potential for development into a biopesticide for the control of this pest in South Africa.
荔枝异形小卷蛾和澳洲坚果桃蛀果蛾是南非的荔枝和澳洲坚果的农业害虫，具有某些市场的植物检疫地位。目前的控制方法依赖于化学、文化和经典生物控制。然而，尚未开发出微生物控制选项。从实验室饲养的群体中回收了来自荔枝异形小卷蛾的一种 Alphabaculovirus，并通过透射电子显微镜（TEM）对其形态特征进行了描述。对包埋体的分析表明，存在一种大小在 421 到 1263nm 之间的单一 NPV（SNPV）。使用通用引物对 polh 基因区域进行 PCR 扩增和测序，然后进行 BLAST 分析，显示与 Epinotia granitalis NPV 的部分 polh 基因序列具有 93%的相似性。进一步的遗传特征涉及对基因组 DNA 进行单一限制内切酶（REN）消化，以生成与其他杆状病毒物种和同一病毒的潜在新分离株进行比较的图谱。对病毒的完整基因组进行了测序、组装和分析，以进行更全面的遗传分析。基因组长度为 115728 个碱基对（bp），GC 含量为 37.2%。共鉴定出 126 个开放阅读框（ORFs），它们之间几乎没有重叠，并且没有方向偏好。生物测定用于确定 NPV 对荔枝异形小卷蛾的毒力。NPV 对荔枝异形小卷蛾具有毒力，LC 值为 6.46×10OBs/ml，LC 值为 2.46×10OBs/ml，时间死亡率在 76.32 小时到 93.49 小时之间。这是首次描述从荔枝异形小卷蛾中分离和遗传特征描述的新型 SNPV，它有可能开发成一种用于控制南非这种害虫的生物农药。
