催青温度对家蚕二化性品种丙酮酸脱氢酶激酶基因(BmPDK)表达的影响

Influence of Incubation Temperature on Expression of Pyruvate Dehydrogenase Kinase Gene in Bivoltine Bombyx mori Varieties

丙酮酸脱氢酶激酶(PDK)在生物体的新陈代谢中具有重要的生理功能。为了探讨家蚕(Bombyx mori)PDK基因的表达特性,用蛾区半分法将二化性家蚕品种的活化越年卵(丙2期)分别以常温(25℃)光照和低温(15℃)黑暗催青,通过实时荧光定量PCR技术检测分析2种温度催青处理后家蚕不同发育阶段和不同组织的BmPDK表达水平。常温光照催青区BmP-DK的表达水平表现出发育时期和组织差异:胚胎发育阶段BmPDK在己4期的表达水平最高,其次是戊2、己3和己5期;幼虫发育阶段BmPDK的表达水平在蚁蚕期极显著高于其它龄期,5龄期在卵巢和精巢的表达水平高于其它组织;蛹期BmPDK的表达水平比其它发育时期低;成虫期的表达水平与胚胎发育末期相当,其中雌蛾的脂肪体和卵巢中BmPDK的表达水平较高。推测BmPDK在家蚕胚胎发育末期及产卵过程中有重要作用。催青温度影响BmPDK在家蚕各发育时期及卵巢组织中的表达水平:胚胎发育阶段戊2期BmPDK的表达水平为常温催青区显著高于低温催青区,己3～己5期常温催青区BmPDK的表达呈低-高-低的趋势,而低温催青区则呈上升趋势;蚁蚕期BmPDK表达水平为低温催青区极显著低于常温催青区;蛹期和成虫期卵巢中,常温催青区BmPDK的表达水平极显著高于低温催青区。催青温度对二化性家蚕BmPDK的表达的影响主要出现在胚胎戊2期、胚胎己3期～蚁蚕期、蛹期、成虫期。

Pyruvate dehydrogenase kinases（PDKs） play important physiological roles in metabolism of organisms.To study the expression patterns of Bombyx mori PDK gene（BmPDK）,half-batch method was employed to incubate the activated over-wintering eggs of bivoltine silkworm strain at normal temperature（25 ℃） with illumination and at low temperature（15 ℃） in darkness,respectively.Real-time fluorescent quantitative PCR was used to determine the expression levels of BmPDK gene at different developmental stages and in various tissues.The results showed that,in normal temperature and illuminated incubation group,BmPDK expression levels were varied with different stages and tissues.During embryonic developmental phase,the peak expression level of BmPDK was at head pigmentation stage,followed by those at late bulge stage,trachea coloring stage and body pigmentation stage.During larval developmental phase,the newly hatched larvae showed the highest expression level which was significantly higher than those of other stages.In the 5th instar larvae,the expression levels of BmPDK in ovary and testis were higher than other tissues.In pupal stage,BmPDK expression level was lower than those of other developmental stages.And in adult stage,BmPDK gene expression level was close to that at the end of embryonic stage,and was relatively higher in fat body and ovary of female moths.It is suggested that BmPDK plays important roles during the late stages of embryonic development and during oviposition of moths.Incubation temperatures influenced the expression of BmPDK gene in all developmental stages and in ovarian tissue.In late bulge stage of embryo,BmPDK gene expression level was significantly higher in normal temperature group than in low temperature group.From trachea coloring stage to body pigmentation stage,the BmPDK gene showed a low-high-low expression pattern in normal temperature group,while it displayed an ascendant pattern in low temperature group.But in the newly hatched larvae,BmPDK gene expression level was significantly lower in low temperature group than in normal temperature group.In ovaries of pupa and adult,BmPDK gene expressed at extremely significantly higher levels in normal temperature group than in low temperature group.It was shown that the influence of incubation temperatures on expression of BmPDK gene occurs mainly at embryonic late bulge stage,trachea coloring stage to hatching stage,and at pupa and adult stages.