Jacquet C, Delecolle B, Raccah B, Lecoq H, Dunez J, Ravelonandro M
INRA, Station de Pathologie Végétale, Centre de Recherche de Bordeaux, Villenave d'Ornon, France.
J Gen Virol. 1998 Jun;79 ( Pt 6):1509-17. doi: 10.1099/0022-1317-79-6-1509.
Aphid transmission of a non-aphid-transmissible strain of zucchini yellow mosaic virus (ZYMV-NAT) occurs in transgenic plants expressing the plum pox potyvirus (PPV) coat protein (CP) gene. Heteroencapsidation has been shown to be responsible for this modification in the epidemiological characteristics of the infecting virus. In order to prevent this biological risk, several modified PPV CP constructs were produced that were designed to interfere with heteroencapsidation itself or to block aphid transmission of heteroencapsidated virions. These constructs were first expressed in Escherichia coli in order to check for the accumulation of pseudo-particles by electron microscopy. Virus-like particles (VLPs) were found with the full-length CP and with a PPV CP lacking the DAG amino acid triplet involved in aphid transmission. However, no VLPs were observed with CP lacking R220, Q221 or D264, amino acids known to be essential for the assembly of other potyvirus CPs. Transgenic Nicotiana benthamiana lines expressing the different PPV CP constructs were infected with ZYMV-NAT. Aphid transmission assays performed with these plants demonstrated that the strategies developed here provide an effective means of minimizing the biological risks associated with heteroencapsidation.
在表达李痘马铃薯Y病毒（PPV）外壳蛋白（CP）基因的转基因植物中，西葫芦黄花叶病毒（ZYMV-NAT）的非蚜虫传播株系可通过蚜虫传播。异源包被已被证明是造成感染病毒流行病学特征这种改变的原因。为了预防这种生物学风险，构建了几种修饰的PPV CP构建体，其设计目的是干扰异源包被本身或阻断异源包被病毒粒子的蚜虫传播。这些构建体首先在大肠杆菌中表达，以便通过电子显微镜检查假颗粒的积累情况。在全长CP以及缺少参与蚜虫传播的DAG氨基酸三联体的PPV CP中发现了病毒样颗粒（VLP）。然而，在缺少R220、Q221或D264（已知对其他马铃薯Y病毒CP组装至关重要的氨基酸）的CP中未观察到VLP。用不同的PPV CP构建体表达的转基因本氏烟草品系被ZYMV-NAT感染。对这些植物进行的蚜虫传播试验表明，这里开发的策略提供了一种有效手段，可将与异源包被相关的生物学风险降至最低。
