长时间低温处理有助于加强黄瓜花叶病毒CMV-BF 2b基因的多态性

将被黄瓜花叶病毒CMV-BF株系侵染的三生烟(Nicotiana tabacum var.Samsun NN)的不同单株分成两组分别置于高温(30±5℃)和低温(10±5℃)条件下,观察和分析CMV-BF侵染30、80 d时植株的症状表现及CMV2b基因的序列变异规律。结果表明:侵染30d时,在高温环境中的植株表现出畸形叶片较多、病毒症状较严重的现象,而低温培养的植株细弱,部分叶片大面积白化;2b基因DNA序列的多态性也以高温处理组略高于低温组,但差异未达到显著水平。侵染80 d时,高温组植株的病毒症状有所恢复,畸形叶片减少,而低温组植株除白化现象更严重外,畸形叶片增多;2b基因的多态性以低温处理组明显高于高温组,且达到显著水平(P0.05)。因此,长时间低温处理有助于加强CMV-BF2b基因的多态性,而且2b基因的多态性可能与植株的病毒症状表现相关。

Long-term treatment of low temperature enhanced the polymorphism of Cucumber mosaic virus-BF 2b gene

CMV-BF infected tobacco(Nicotiana tabacum var.Samsun NN) plants were cultured at two different temperatures(30±5℃ and 10±5℃) for 30 and 80 days, respectively.Viral symptom was observed and 2b gene sequences were analyzed.The results showed that at 30 dpi(days post infection) the hosts exhibi-ted serious viral symptom with many malformed leaves under high temperature(30±5℃), but the plants grown under low temperature(10±5℃) seemed very thin with many white leaves.There were more polymorphisms in CMV-BF 2b gene under high temperature than under low temperature(P>0.05).However, at 80 dpi, the viral symptom was somewhat attenuated in the high temperature host group;whereas, much more serious symptom with many malformed leaves and dead plants occurred on the plants grown under low tempe-rature.The number of polymorphisms of CMV-BF 2b gene was statistically higher in the plants under low temperature than of high temperature(P<0.05) at 80 dpi.Therefore, low temperature of long-term enhanced the polymorphisms of CMV-BF 2b gene, and it was positively correlated with symptom.