The Effect Of Temperature On Gene Sequence Of Cucumber Mosaic Virus And Tobacco Mosaic Virus

Plant RNA viruses are important factors badly affecting production and quality of crops.Of them,Cucumber Mosaic Virus(CMV) and Tobacco Mosaic Virus(TMV) are serious and world-widespread plant RNA viruses.Many researches on them were carried on,while changes of virus gene sequences, induced by the same virus isolates used to research the virus-host interactions,had been never reported in previous study.In this paper,changes of gene sequences in virus from infected tobaccos by virus isolates were studied.Different tobacco plants infected with three virus isolates,i.e.CMV-BG, CMV-BF and TMV-1,respectively,were cultured under various conditions.30 days later,symptoms of those infected plants were observed and analyzed, expression of the referenced genes was detected,and then those genes(i.e.2b,CP and MP) were cloned and sequences of them were analyzed.The results were as follows.â…°.When the tobacco plants infected with CMV-BG were respectively cultured at low temperature and room temperature(as control type) for 30 days,there was not co-relation on the expression of 2b or CP between the two different conditions. However,both of 2b and CP gene polymorphism at low temperature were higher than that at room temperature.It was shown that low temperature enhanced polymorphism of CMV-BG genome,especially 2b gene.â…±.When the tobacco plants infected with CMV-BF were respectively cultured at low temperature,high temperature and room temperature(as control type) for 30 days,the 2b gene polymorphisms at low temperature(Pi=0.00143) and high temperature(Pi=0.00142) were higher than that at room temperature(Pi=0.00117). In addition,the CP gene polymorphisms at low temperature(Pi=0.00200) and high temperature(Pi=0.00260) were also higher than that at room temperature (Pi=0.00180).Furthermore,at low temperature and high temperature,2b gene polymorphism in the plants with lower percentage of infection was higher than that with higher percentage of infection.It was proved that low temperature and high temperature all improved polymorphism of CMV-BF genome.â…².When tobacco plants were infected with TMV-1,the both of low temperature and high temperature all enhanced CP and MP gene polymorphism. The CP and MP gene polymorphisms at low temperature and high temperature all were significantly higher than that at room temperature.As mentioned above,it was concluded that temperature was an effective factors on virus gene mutation during the virus-host interactions.Both stresses of low temperature and high temperature enhanced virus gene polymorphism.