采用qRT-PCR技术,对不同温度(10℃,15℃,20℃,25℃)以及低温(10℃,15℃)和盐度(10,35)联合作用下拟穴青蟹(Scylla paramamosain)(甲壳长3.7~5.8 cm,体质量80~100 g) ANT2基因的表达进行了检测。结果表明：在4个温度下肝胰腺、肌肉、鳃中 ANT2基因表达量依次为低、中、高,存在组织表达特异性。随着温度降低, ANT2基因总体上趋低表达,但在15℃时ANT2基因在肌肉(1~12 h)和鳃中均显著高于20℃( P<0.05)。该结果提示, ANT2基因与能量代谢相关,且在一定低温下被诱导表达,可能参与低温胁迫的应答。相同低温下,3种组织中ANT2基因在盐度10的表达量通常高于盐度35的(P<0.05),说明低温下低盐环境有利于提高青蟹体内代谢,增强耐寒能力。%The mud crab Scylla paramamosain, a eurythermal and euryhaline species, is a commercially exploited crab inhabiting the southeastern coast of China. In recent years, mud crab aquaculture has suffered as a result of unsettled weather, which has led to a seasonal temperature and salinity changes in the sea water. This study aims to explore the molecular mechanism of cold tolerance in S. paramamosain by examining the expression of adenine nucleotide trans-locase 2 (ANT2) at different temperatures and salinities. ANT belongs to the mitochondrial carrier superfamily (MCF). It is the most abundant inner membrane protein of the mitochondrion and is responsible for the transport of ADP and ATP in the cytoplasm and mitochondrial matrix through the inner mitochondrial membrane. In this study, the relative expression of ANT2 mRNA was detected using real-time quantitative polymerase chain reaction at different tempera-tures (10℃, 15℃, 20℃, 25℃), and low temperatures (10℃, 15℃) combined with salinity (10, 35) in mud crabs (cara-pace width 3.7–5.8 cm, body weight 80–100 g). Real-time qPCR indicated that, at different temperatures, ANT2 was expressed in the hepatopancreas, muscle and gill. The relative expression of ANT2 mRNA was lowest in the hepatopan-creas, at a medium level in muscle, and highest in the gill, and the results indicated that the expression of ANT2 was tissue-specific. With declining temperature, the expression of ANT2 mRNA decreased generally, but at 15℃in the mus-cle (1–12 h) and gill, the expression of ANT2 was significantly higher than that at 20℃(P<0.05). The expression pattern of ANT2 at different temperatures demonstrated that it might be associated with energy metabolism, and participate in stress responses at a certain range of low temperatures, stimulating the expression of ANT2 in the mud crab. At the same temperature, the expression of ANT2 at a salinity of 10 was significantly higher than at the higher salinity of 35 (P<0.05), which indicated low salinity might be helpful for metabolism in mud crabs, enhancing cold resistance. This research might provide theoretical guidance for crab aquaculture and management to some extent.
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