Abstract: 【Aim】 Laccase-1 (LAC1) plays an important role in whiteflyplant interaction. The aim of this study is to explore the variations in expression patterns of LAC1 gene in two whitefly species, Bemisia tabaci MEAM1 and Trialeurodes vaporariorum. 【Methods】 The laccase-1 activity was measured in the saliva of B. tabaci MEAM1 and T. vaporariorum. The LAC1 gene from T. vaporariorum was cloned and sequenced. The expression profiles of LAC1 in different developmental stages and adult tissues of the two whiteflies were assayed by qPCR and compared. The LAC1 expression levels, adult survival rate and the number of eggs laid by the two whiteflies after feeding on tomato plants sprayed with 0.5 mmol/L salicylic acid (SA) were detected and compared. 【Results】 The laccase-1 activities in saliva of B. tabaci MEAM1 and T. vaporariorum had no significant differences. A 639 bp intermediate fragment of LAC1 gene was cloned from T. vaporariorum. Developmental expression profiles revealed that LAC1 was expressed in various developmental stages of both species, and its expression level increased gradually in adult stage of B. tabaci MEAM1, but showed no significant difference among various developmental stages of T. vaporariorum. At the adult stage, the transcript level of LAC1 was higher in B. tabaci MEAM1 than that in T. vaporariorum. Tissue expression profiles revealed that LAC1 was expressed in the cephalothorax, midgut and abdomen wreckage of adults of both whiteflies, and showed the highest transcript level in the midgut. The survival rate of B. tabaci MEAM1 adults feeding on tomato plants sprayed with SA decreased as the feeding time extended, and was significantly different from that in the control (feeding on tomato plants sprayed with water). At 14 d after adult emergence, the survival rate of B. tabaci MEAM1 feeding on tomato plants sprayed with SA was only half the control, while that of T. vaporariorum feeding on tomato plants sprayed with SA showed no significant difference from the control. In addition, the expression level of LAC1 and the number of eggs laid were higher in B. tabaci MEAM1 than those in T. vaporariorum regardless of whether they fed on tomato plants sprayed with SA or the control plant. 【Conclusion】 The results indicate that there are differences in the expression patterns of LAC1 between B. tabaci MEAM1 and T. vaporariorum, and this may play a role in the competition between the two species.

Key words: Bemisia tabaci MEAM1, Trialeurodes vaporariorum, laccase-1, expression profile, qPCR