漆酶-1基因在烟粉虱MEAM1隐种和温室粉虱中的表达模式比较

Comparison of expression patterns of laccase-1 gene in Bemisia tabaci MEAM1 and Trialeurodes vaporariorum (Hemiptera:Aleyrodidae)

【目的】漆酶-1(LAC1)在粉虱-植物互作中发挥重要作用,本研究旨在探讨烟粉虱Bemisia tabaci MEAM1隐种和温室粉虱Trialeurodes vaporariorum两种存在竞争关系的粉虱中LAC1基因表达模式是否存在差异。【方法】测定烟粉虱MEAM1隐种和温室粉虱唾液漆酶-1活力;对温室粉虱LAC1基因进行了克隆和测序;通过荧光定量PCR测定和比较了LAC1在两种粉虱不同发育阶段和成虫不同组织中的表达谱以及取食外施水杨酸(0. 5 mmol/L)的番茄植株后两种粉虱不同发育阶段和成虫不同组织中LAC1的表达水平,同时检测了成虫存活率和产卵量。【结果】酶活力测定结果表明两种粉虱的唾液中漆酶-1活力差异不显著。温室粉虱PCR扩增后得到大小639 bp的LAC1基因中间片段。发育表达谱结果表明,LAC1基因在两种粉虱各个发育阶段均有表达,在烟粉虱MEAM1隐种成虫期表达量逐渐升高,而在温室粉虱各发育时期的表达量无显著差异;烟粉虱MEAM1隐种成虫期LAC1的表达量高于温室粉虱。组织表达结果表明,LAC1在两种粉虱成虫的头胸部、中肠和腹部残骸中均有表达,但在中肠中丰度最高。取食外施水杨酸番茄植株的烟粉虱MEAM1隐种,随取食时间的延长成虫存活率下降,与对照(取食喷施清水的植株)相比差异显著。羽化后14 d时,取食外施水杨酸植株的烟粉虱MEAM1隐种存活率仅为对照的一半,而取食外施水杨酸植株的温室粉虱的存活率与对照相比差异不显著。无论是取食外施水杨酸的植株还是取食对照植株,烟粉虱MEAM1隐种体内LAC1表达量和产卵量均高于温室粉虱。【结论】LAC1在两种粉虱体内表达模式存在差异,这可能在两种粉虱的竞争适应中具有一定作用。

【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 LAC 1 in different developmental stages and adult tissues of the two whiteflies were assayed by qPCR and compared.The LAC 1 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 LAC 1 gene was cloned from T.vaporariorum.Developmental expression profiles revealed that LAC 1 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 LAC 1 was higher in B.tabaci MEAM1 than that in T.vaporariorum.Tissue expression profiles revealed that LAC 1 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 LAC 1 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 LAC 1 between B.tabaci MEAM1 and T.vaporariorum,and this may play a role in the competition between the two species.