圆唇散白蚁补充生殖蚁发育过程中的卵黄蛋白原基因的表达及卵子发生

Vitellogenin gene expression and oogenesis during the development of the neotenic reproductive caste of Reticulitermes labralis

【目的】研究圆唇散白蚁Reticulitermes labralis(Hsia)补充生殖蚁分化及发育过程中卵黄蛋白原(Vitellogenin,Vg)基因的表达、卵母细胞的发育以及子代品级分化。【方法】通过使用实时定量PCR(Real-time quantitative polymerase chain reaction)技术测定补充生殖蚁从分化到产卵的过程中Vg基因相对表达量的动态变化;采用组织染色的方法进行卵母细胞发育阶段的观察;对子代的数量及分化进行统计分析。【结果】补充生殖蚁发育过程中,Vg基因表达呈现先升高后降低的动态变化模式。在补充生殖蚁分化后的第10天开始形成具卵黄的卵母细胞,在20 d时具卵黄卵母细胞的数量达到最高值。第1个月至第3个月,补充生殖蚁的产卵数逐渐增加,分别为(2.45±1.43)、(7.68±2.53)和(12.10±7.09)粒。第3个月,巢内开始出现幼蚁,数量为(5.15±2.41)头;第10个月,巢群内有工蚁、前兵蚁和兵蚁的分化,分别为(17.03±2.28)、(1.45±0.31)和(0.79±0.18)头。【结论】在新建巢群中,若蚁的分化在工蚁和兵蚁分化之后。圆唇散白蚁若蚁在巢群需要的时候,可以在很短时间内转化为补充生殖蚁;Vg基因的表达水平与卵母细胞的卵黄形成相关,Vg基因表达量的增加启动了卵母细胞的卵黄摄取过程。虽然单个补充生殖蚁产卵量不如单个原始生殖蚁的多,但是在一个巢内补充生殖蚁总的产卵数目要远远超过原始生殖蚁,因为补充生殖蚁的数量比原始生殖蚁的数量多。因此补充生殖蚁对巢群稳定和发展具有重要作用。

[Objectives] To study Vitellogenin（Vg） gene expression and oocyte development in the neotenic reproductive caste of Reticulitermes labralis（Hsia）. [Methods] Vitellogenin gene expression was measured using Real-time quantitative polymerase chain reaction（PCR） during the development of individuals of the neotenic reproductive caste and oogenesis was observed with the histological dyeing method. [Results] The level of Vg gene expression initially increased, then declined during development. There were vitellogenic oocytes in the ovarioles on day 10 of development, and development had reached the late vitellogenesis stage on day 20. From the first to the third month, the mean number of eggs laid by members of the neotenic reproductive caste was（2.45±1.43）,（7.68±2.53） and（12.10±7.09）, respectively. Larvae had hatched by the third month; the mean number of larvae was（5.15±2.41）. Workers, pre-soldiers and soldiers had developed by the tenth month, the mean numbers of these castes were（17.03±2.28）,（1.45±0.31） and（0.79±0.18）, respectively. [Conclusion] Nymphs differentiate later than workers and soldiers in initial colonies and can quickly develop into the neotenic reproductives when required. The level of Vg gene expression is related to the development of vitellogenic oocytes and an increase in Vg gene expression starts the process of vitellogenin uptake in oocytes. Although the mean number of eggs laid by individual members of the neotenic reproductive caste is less than that laid by one primary reproductive, because the number of neotenic reproductives is far more than the single primary reproductive in each colony, the total number of eggs laid by neotenic reproductives far exceeds that produced by primary reproductives. Neotenic reproductives are therefore important to the growth of colonies.