【作者】 王彪；

【导师】 李向东；

【作者基本信息】 山东农业大学 ， 植物病理学， 2009， 硕士

【摘要】 马铃薯Y病毒(Potato virus Y,PVY)是全球性分布的重要病毒,主要危害烟草、马铃薯、辣椒、番茄等茄科作物。本研究从山东安丘和泰安的烟草上分离得到2个PVY分离物AQ4和FZ10。生物学实验表明,这两个分离物在中烟100等12个烟草品种上产生不同程度的花叶和斑驳。通过RT-PCR和5′-RACE克隆并测定了AQ4和FZ10两个PVY分离物的全基因组序列。除了3′-末端poly(A)尾巴,AQ4和FZ10全长分别为9700个和9699个核苷酸,均含有一个大的开放阅读框,均编码由3061个氨基酸组成的多聚蛋白。这一多聚蛋白被9个酶切位点分成10个功能蛋白。通过对全基因组核苷酸的一致率比较分析,分离物AQ4和FZ10与国内外的PVY分离物的核苷酸一致率分别在97.3%-85.3%和95.2%-83.9%之间。AQ4分离物与261-4分离物的核苷酸一致率最高达97.3%,与NIB-NTN分离物的核苷酸一致率最低为85.3%。FZ10分离物与PVY-12分离物的核苷酸一致率最大达95.2%,与PVY-MN分离物的核苷酸一致率最小为83.9%。它们与国内外的PVY分离物的氨基酸一致率分别在98.6%-92.2%和98.5%-91.8%之间。AQ4和FZ10均为N和O株系分离物的重组体。AQ4分离物1-496 nt和2497-9700 nt来源于PVYO株系的分离物Oz,497-2496 nt来源于PVYN株系的分离物CH-605。FZ10分离物1-496 nt和2497-6533 nt来源于PVYO株系的分离物SASA-110,497-2496 nt和6534-9699 nt来源于PVYN株系分离物CH-605。系统进化树结果表明,AQ4属于PVYN:O亚组,而FZ10属于重组的PVYNTN亚组。AQ4和FZ10的基因型分别属于PVYN:O和PVYNTN,有PVYN株系的HC-Pro,但致病型与PVYO株系相同,说明除了HC-Pro外,还有其它基因控制PVY在烟草上引起坏死症状。更多还原

【Abstract】 Potato virus Y (PVY) is one of the most widespread viruses and causes huge losses to solanaceous crops including potato, tobacco, eggplant and tomato.Two PVY isolates, AQ4 and FZ10, were isolated from tobacco plants in Aiqiu and Tai’an of Shandong Province. Both isolates could induce mosaic and mottle in 12 tobacco cultivars including Zhongyan 100.The complete genomic sequences of AQ4 and FZ10 were determined from seven or eight overlapping cDNA clones obtained from RT-PCR and 5′-RACE. Excluding the poly(A) tail, the genome of AQ4 and FZ10 were 9700 and 9699 nucleotides in length, respectively. Both of them encoded a polyproetin of 3061 amino acids, which was then cleaved into ten products by three virus-encoded proteases. AQ4 shared highest identity of 97.3% with isolate 261-4 at nucleotide level, while FZ10 shared highest identity of 95.2% with PVY-12. Both AQ4 and FZ10 were recombinants of N and O parents. The nucleotides (nt) 1-496 and 2497-9700 of AQ4 genome were from isolate Oz (PVYO),while nt 497-2496 from isolate CH-605 (PVYN). The nt 1-496 and 2497-6533 of FZ10 genome were from isolate SASA-110 (PVYO),while nt497-2496 and 6534-9699 were from isolate CH-605 (PVYN).The phylogenetic analysis results showed that AQ4 was clustered to strain PVYN:O while FZ10 PVYNTN. Both of them had N-type HC-Pro. However, neither of them induced necrosis on tobacco. These reulsts implied that there existed other motif besides HC-Pro regulating the veinal necrosis symptom in PVY genome.更多还原