Effect of temperature and light impact on expression of lycopene cyclase gene in tobacco (Nicotiana tabacum L.)

To demonstrate effect of temperature or light intensities on expression of lycopene cyclase gene (lyc-beta), which is one of the critical enzymes in the process of carotenoid synthesis, tobacco leaf discs were treated with different temperatures and light intensities. In this study, orthogonal experiment L-9(3(4)) was adopted to investigate the effect of temperature and light intensity on expression of lyc-beta with semi-quantitative RT-PCR. At same time, lyc-beta expression and contents of carotenoids in different ecological areas were detected. The results indicated that light was a key factor affecting expression of lyc-beta, followed by temperature and the least was the interactions of temperature and light. Results of Duncan's test showed that three factors had no significance in three levels (P<0.5). Results of different light treatments suggested that expression of lyc-beta increased during 2 to 6 h, however, it would inhibit when treatments of light was over 8 h. Moreover, expression of lyc-beta and content of carotenoids were significantly different in Sichuan and Henan (P<0.01), and they were about the same level at the same areas.