中华蜜蜂和意大利蜜蜂耐寒性能差异比较

【目的】研究中华蜜蜂(Apis cerana cerana,简称中蜂)和意大利蜜蜂(Apis mellifera ligustica,简称意蜂)体内抗寒系统的组成,为探究中蜂和意蜂耐寒性能的差异提供理论依据。【方法】试验选取室外相同环境条件越冬的中蜂和意蜂各5群,于2015年12月20日每群随机选取蜜蜂立即测定两者的过冷却点、冰点,比较其耐寒性能差异。然后分别测定蜂体游离水、结合水、脂肪、糖原和蛋白质含量以及海藻糖酶的活性。利用高效液相色谱测定血淋巴中山梨醇、海藻糖、甘露醇的含量。在海藻糖的生物合成通路中确定4个重要调控基因,选择β-action和β-肌动蛋白分别作为中蜂和意蜂的内参基因,采用实时荧光定量PCR检测中蜂和意蜂海藻糖4个相关调控基因在越冬期时m RNA相对表达量的差异。【结果】越冬期中蜂和意蜂过冷却点差异显著,中蜂的过冷却点显著低于意蜂(P0.05),但二者冰点没有显著性差异(P0.05);越冬期中蜂和意蜂蜂体含水量存在显著差异,中蜂体内游离水含量显著低于意蜂(P0.05),而结合水含量显著高于意蜂(P0.05);越冬中期蜂体脂肪含量在两蜂种间差异不显著(P0.05);中蜂和意蜂蜂体和血淋巴蛋白质含量差异不显著(P0.05);意蜂在越冬期时体内糖原含量明显低于中蜂,并且差异显著(P0.05);中蜂血淋巴中甘露醇、山梨醇含量接近于意蜂的两倍,海藻糖含量也相对高于意蜂,差异显著(P0.05);中蜂蜂体和血淋巴的海藻糖酶活性均显著低于意蜂(P0.05);以中蜂为对照组,实时荧光定量PCR检测意蜂的海藻糖酶基因(Tre-2)和尿苷二磷酸葡萄糖焦磷酸化酶基因(UGP)表达量明显高于中蜂(P0.05);而基因Tre-1表达情况相反;海藻糖合成酶基因(TPS)表达量在中蜂和意蜂体内无显著差异(P0.05)。【结论】与意蜂相比,中蜂能够通过降低体内游离水含量,提高糖原和小分子糖含量,调节海藻糖酶活性和相关基因表达等方式降低体内过冷却点,提高自身耐寒性能。

Comparison of Different Cold Resistance betweenApis cerana cerana and Apis mellifera ligustica

【Objective】 the objective of this research is to study the composition of cold resistance system in Apis cerana cerana and Apis mellifera ligustica, and to provide a theoretical basis for the study of the differences of cold resistance between the two species. 【Method】Five A. c. cerana colonies and five A. m. ligustica colonies which overwintered under the same equivalent environment were randomly selected with 10-25 bees in each colony on December 20th, 2015. The supercooling point (SCP) and freezing point (FP) were measured immediately, and their cold tolerance were compared. The free water, bound water, fat, glycogen, protein and the trehalase activities were determined, respectively. Four important regulatory genes were sure through the biosynthetic pathway of trehalose. The relative expression of the four important regulatory genes at mRNA level were detected by real-time fluorescent quantitative PCR in over-wintering period. 【Result】 Compared with A. m. ligustica, the super-cooling point was significantly higher than A. c. cerana (P＜0.05). The freezing point showed no obvious difference (P＞0.05). The free-water content of A. c. cerana was significantly lower than A. m. ligustica (P＜0.05), by contrast the bound-water content of A. c. cerana was obviously higher than A. m. ligustica (P＜0.05). There was no obvious difference in the fat content between A. cerana cerana and A. m. ligustica (P＞0.05). There were no significant differences in the protein content of two bee species (P＞0.05); glycogen content of A. c. cerana had significantly increased than A. mellifera ligustica in mid-winter (P＜0.05). The mannitol, sorbic alcohol content of A. c. cerana was twice as that of A. m. ligustica in the hemolymph (P＜0.05). The content of trehalose in A. c. cerana was obviously higher than A. m. ligustica (P＜0.05). The trehalase activity of A. c. cerana significantly reduced compared with A. m. ligustica in the body and hemolymph (P＜0.05). Compared with A. c. cerana, the relative expression levels of Tre-2 and UGP had significantly increased in A. m. ligustica (P＜0.05), but Tre-1 was obviously lower (P＜0.05). There was no obvious difference in the relative expression levels of TPS between A. c. cerana and A. m. ligustica (P＞0.05).【Conclusion】A. c. cerana decreases supercooling point by reducing the content of free water, increasing the content of glycogen and low molecular sugar, regulating trehalase activity related genes expression to increase its cold resistance.