为了研究团头鲂嗅觉器官的发育过程和嗅觉受体基因 (ORs)在嗅囊发育不同时期的组织表达模式，实验基于组织学、形态学及实时荧光定量PCR技术 (qRT-PCR)的方法进行了探究。组织形态学结果显示，团头鲂嗅觉器官位于后背部和两侧眼睛前方，嗅囊紧贴于嗅腔底部，形状近似椭圆形，嗅基板沿着头尾方向平行排列。嗅囊在团头鲂刚孵化时出现嗅窝外围凹进的痕迹，随后凹进处长出嗅窝，并在中央出现长条形的嗅基板。随着仔鱼的生长发育，单侧嗅囊初级嗅基板由疏松逐渐排列紧密，嗅基板隆起高度、数量及嗅囊总体表面积逐渐增加，在成鱼阶段趋于稳定。qRT-PCR结果显示，代表性ORs在团头鲂发育不同时期的组织中表达模式各异，其中Beta-2、9、10、11在胚胎发育期的囊胚期、胚孔闭合期及嗅板期高表达；Beta-2、9、10、11和Epsilon-7在仔稚鱼期的3~15 dpf中微弱表达，在30~60 dpf时期高表达；Beta-2、10、11及Epsilon-6、7、10、13在幼鱼期至成鱼期嗅囊中高表达，Beta-2、10、9、11及Epsilon-7、10、13在3月龄团头鲂嗅球中高表达；Beta-2、10在幼鱼期至成鱼期脑中低表达。研究表明，团头鲂嗅觉器官的发育进程与ORs表达相关，不同发育时期ORs主要表达部位均在嗅囊中。本研究对进一步探究ORs的功能提供理论支持，也为后续深入研究鱼类嗅觉识别机制奠定了基础。

The olfactory organs development of blunt snout bream (Megalobrama amblycephala) was investigated using histological and morphological methods. The results revealed that the olfactory organs of M. amblycephala were positioned on the back and in front of the eyes. The olfactory epithelium (OE) was oval-shaped near the base of the olfactory cavity. The olfactory placodes were parallelly arranged in the cranio-caudal direction. There were concave marks on the olfactory fossa’s periphery when fish were hatching out. Afterwards, an elongated olfactory placode was formed in the olfactory fossa’s core. The arrangement of the primary olfactory placodes of the unilateral OE were from loose to tight with M. amblycephala growth. The height and number of the olfactory placodes, as well as the overall surface area of the OE gradually expanded and stabilized in the adult stage. qRT-PCR were used to studied the expression patterns of representative ORs. The results showed that ORs expression differed in different stages and tissues of M. amblycephala. ORs Beta-2, 9, 10 and 11 were highly expressed at several stages of embryonic development, including the blastocyst stage, blastopore closure stage and olfactory lamellae stage (P<0.01). Beta-2, 9, 10, 11 and Epsilon-7 were weakly expressed at 3 to 15 dpf, in the larval and juvenile stages, but highly expressed at 30 to 60 dpf (P<0.01). Beta-2, 10, 11 and Epsilon-10, 13 were strongly expressed in the OE of 4 periods from juvenile to adult stages (including 3, 6, 12 and 24-month-old) (P<0.05). Beta-2, 9, 10, 11 and Epsilon-7, 10, 13 were also highly expressed in the OB (olfactory bulb) in 3-month-old M. amblycephala (P<0.01), but not expressed in the 6 to 24-month-old stage. Beta-2, 11 expression levels were low in the brain at the 4 age periods (P<0.05). These findings provide theoretic evidence for further exploration of the functions of ORs in fish, and deepen the research on fish olfactory recognition.

Q 786；S 917.4

国家自然科学基金 (32273109)；中央高校基本科研业务费专项 (2662020SCQD002)；国家现代农业产业技术体系建设项目 (CARS-45-01)