Effects of point mutations in the readthrough domain of the beet western yellows virus minor capsid protein on virus accumulation in planta and on transmission by aphids
Effects of point mutations in the readthrough domain of the beet western yellows virus minor capsid protein on virus accumulation in planta and on transmission by aphids
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DOI：
10.1128/jvi.74.3.1140-1148.2000
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发表时间：
2000-02-01
影响因子：
5.4
通讯作者：
Ziegler-Graff, V
中科院分区：
文献类型：
--
作者：
Brault, V;Mutterer, J;Ziegler-Graff, V
将点突变引入到甜菜西部黄病毒次要衣壳蛋白P74读透结构域的Eve保守序列基序或附近。对该突变病毒进行了测试，证明其在农染植物中有效积累，并能通过其蚜载体桃蚜（Myzus persicae）传播。通过子代病毒的序列分析，验证了突变体在农虫侵染和蚜虫侵染植物中的稳定性。发现只有突变Y201D在农感染后强烈抑制病毒在植物中的积累，但在该位点通过逆转或伪逆转恢复了高积累水平。5个突变体中有4个具有较差的蚜虫传播性，但在3个病例中，通过假逆转或第二位点突变恢复了成功的传播。非保守基序PVT（32-34）中相同的第二位点突变被证明可以补偿PVT序列两侧各一个的两个不同的初级突变（R24A和E59/D60A）。在后一种情况下，将突变病毒显微注射到蚜虫血腔中后，PVT基元的第二位点突变恢复了病毒从血腔通过副唾液腺移动的能力，但不允许病毒穿过将肠与血腔分开的上皮。突变病毒成功穿过这两个屏障的同时，还伴随着A59向E或T的转化，这表明该区域读透结构域的不同特征在传播过程的不同阶段起作用。
Point mutations were introduced into or near Eve conserved sequence motifs of the readthrough domain of the beet western yellows, virus minor capsid protein P74. The mutant virus was tested for its ability to accumulate efficiently in agroinfected plants and to be transmitted by its aphid vector, Myzus persicae. The stability of the mutants in the agroinfected and aphid-infected plants was followed by sequence analysis of the progeny virus. Only the mutation Y201D was found to strongly inhibit virus accumulation in plants following agroinfection, but high accumulation levels were restored by reversion or pseudoreversion at this site. Four of the five mutants were poorly aphid transmissible, but in three cases successful transmission was restored by pseudoreversion or second-site mutations. The same second-site mutations in the nonconserved motif PVT(32-34) were shown to compensate for two distinct primary mutations (R24A and E59/D60A), one on each side of the PVT sequence. In the latter case, a second-site mutation in the PVT motif restored the ability of the virus to move from the hemocoel through the accessory salivary gland following microinjection of mutant virus into the aphid hemocoel but did not permit virus movement across the epithelium separating the intestine from the hemocoel. Successful movement of the mutant virus across both barriers was accompanied by conversion of A59 to E or T, indicating that distinct features of the readthrough domain in this region operate at different stages of the transmission process.