CAJ | 학술논문

温度和光照是昆虫近日节律基因表达的授时因子,也是影响家蚕滞育的决定因素.为了解家蚕滞育与近日节律调控的关系,研究了滞育诱导发生温度与光照对家蚕近日节律基因per表达的影响.家蚕整个世代在25 ℃高温环境下,或幼虫期与蛹期在20 ℃的较高温度下,per基因在黑暗环境中的转录水平高于光照环境.家蚕幼虫及蛹期在相同光照条件下,per基因转录水平在高温环境中高于低温环境,黑暗环境下又呈现20 ℃＞25 ℃＞15 ℃的变化趋势,且温度的影响大于黑暗环境;在25 ℃持续光照条件(25LL)下,胚后时期per基因的表达水平高于15 ℃持续黑暗的条件(15DD),而20 ℃及光照与黑暗各12 h条件(20LD)下变化更加敏感,这与温度和光照对家蚕滞育的诱导作用一致.在处女蛾和卵产出后0.5 h的未受精蚕卵中都检测到了高水平的母源per基因mRNA.亲代卵催青期的单因子25 ℃高温或黑暗、以及20LD,都会引起子代卵内per基因mRNA水平的上调,这种上调只出现在滞育出现或活化发育的转折时间点(卵龄72 h)之前.家蚕滞育诱导温度和光照条件直接影响per基因在整个世代的差异表达,该基因在卵期的表达与胚胎滞育性差异密切关联.
온도화광조시곤충근일절률기인표체적수시인자,야시영향가잠체육적결정인소.위료해가잠체육여근일절률조공적관계,연구료체육유도발생온도여광조대가잠근일절률기인per표체적영향.가잠정개세대재25 ℃고온배경하,혹유충기여용기재20 ℃적교고온도하,per기인재흑암배경중적전록수평고우광조배경.가잠유충급용기재상동광조조건하,per기인전록수평재고온배경중고우저온배경,흑암배경하우정현20 ℃＞25 ℃＞15 ℃적변화추세,차온도적영향대우흑암배경;재25 ℃지속광조조건(25LL)하,배후시기per기인적표체수평고우15 ℃지속흑암적조건(15DD),이20 ℃급광조여흑암각12 h조건(20LD)하변화경가민감,저여온도화광조대가잠체육적유도작용일치.재처녀아화란산출후0.5 h적미수정잠란중도검측도료고수평적모원per기인mRNA.친대란최청기적단인자25 ℃고온혹흑암、이급20LD,도회인기자대란내per기인mRNA수평적상조,저충상조지출현재체육출현혹활화발육적전절시간점(란령72 h)지전.가잠체육유도온도화광조조건직접영향per기인재정개세대적차이표체,해기인재란기적표체여배태체육성차이밀절관련.
In insects, temperature and photoperiod are the two main zeitgebers, which can affect the expression of circadian genes, and also are the determinant of diapause in Bombyx mori. In order to understand the relationship between diapause and the regulation of circadian rhythm in Bombyx mori, we investigated the effects of diapause-inducing incubation temperature and photoperiod on per gene expression. The results showed that per transcriptional levels in dark environment were significantly higher than those in light environment when all developmental stages of the Bombyx mori were under high temperature (25 ℃) or its larval and pupal stages were under relatively high temperature (20 ℃). The mRNA level of per gene under high temperature was higher than that under low temperature when the larval and pupal stages were under the same photoperiod. In addition, the mRNA transcriptional level of per gene in dark environment was in the order of 20 ℃＞25 ℃＞15 ℃. Besides, the effect of temperature on per gene expression was more obvious than darkness. During the postembryonic developmental stage, the expression level of per gene under 25 ℃ and continuous illumination (25LL) was higher than that under 15 ℃ and continuous darkness (15DD), while the expression of per gene under 20 ℃ and 12 h light/dark photoperiod (20LD) was more sensitive, being consistent with the induction of temperature and photoperiod on Bombyx mori diapause. Both eggs from virgin moths and unfertilized eggs at 0.5 h presented a high level of maternal per mRNA. While developing embryos of the Bombyx mori maternal generation were exposed to high temperature (25 ℃) or darkness and 20LD, their progeny exhibited up regulation of per mRNA levels. However, this up regulation only occurred before egg age of 72 h, a turning time point to generate diapause or to activate other developmental events. In conclusion, the diapause-inducing incubation temperature and photoperiod directly affect the differential expression of per gene during the whole life cycle of Bombyx mori, and the expression of per gene was closely related to the difference of embryonic diapause status.