| The honeybee is a real social insect.Its waggle dance can deliver information about distance and direction of target resources,so it is good for bees to find a better nest and efficiently collect quality sources of pollen and nectar,further to improve the adaptability of bees.Currently,there have been numerous studies on the waggle dance of bee,but few studies investigated the molecular mechanism of this complex behavior.The success of whole genome sequencing on the western honeybee(Apis mellifera)and continuous development of molecular biological technology enable screening genes associated with this kind of behavior to materialize.The genes screening on the waggle dance of western honeybee can make us further understand this behavior at the molecular level and pave the way for revealing the molecular mechanism of the behavior.As the behavior of honeybee is highly regulated by its brain,the genes related to the waggle dance of honeybee is inevitably highly expressed in the brain of dancing bee.So we captured bees in the same colony which had collected resources in the natural environment and returned to the beehive,and divided them into three groups:DB,the bee which was dancing;DEB,the bee whose dance was ended;QB,which had danced in the daytime and became quiet at night.The differential genes in their brains were screened by using the second-generation high throughput sequencing technology DGE(Digital Gene Expression Profiling),so as to find out genes related to bee’s waggle dance as many as possible.The DGE result shows:the number of differential genes in brains between DB and QB was 102,among which 96 genes were up-regulated and 6 were down-regulated in DB;the number of differential genes between DEB and QB was 327,among which 275 genes were up-regulated and 52 were down-regulated in DEB;no differential genes were found between DB and DEB.Furthermore,10 differential genes were testified through qPCR(quantitative real-time PCR)and verification result were consistent with the sequencing result,so the sequencing result above is reliable.Although some differential genes were highly expressed in brains of DB and DEB,it only indicated that they were probably related with wagging dance of honeybee.Because QB refering to the bee which was in a quiet state at night,but both DB and DEB were bees in a movement state in the daytime,so those genes highly expressed in brains of DB and DEB could also be related with the circadian rhythm or movement of the honeybee.As for the honey bee which collected sugar water at a fixed site and danced,their activities in the daytime were mainly divided into dancing and collecting.The dancing bees would be quiet in a short period of time after sugar water was taken away.Comparing the dancing state with the collecting state,impacts of the circadian rhythm and the movement could be excluded.And the comparison between the dancing states with the quiet state in the daytime could exclude the impact of the circadian rhythm.So we captured bees in five different states:(1)dancing a round,(2)dancing was over,(3)just started collecting,(4)collecting sugar water for 1 minute,(5)quiet in the daytime.For 8 genes which were both highly expressed in brains of DB and DEB,their expressions in five states above were measured through qPCR,so as to further screen out genes associated with bee’s waggle dance.The qPCR result shows:expressions of GB48446,GB51125 in brains of bees,either dancing a round or dancing was over,were significantly or extremely significantly higher than the expressions of the other three states,thus the two genes were closely related to the bee’s waggle dance;expressions of GB50091,GB50609 and GB50871 in brains of bees dancing a round or dancing was over were significantly higher than those in honeybees being quiet in the daytime,but not significantly different from those of bees just collected and collecting sugar water for 1 minute,thus the three genes might be related to the bee’s dancing;no significant differences in expressions of GB44503,GB46697 or GB51011 were found in brains of bees in any of these states,accordingly the three genes maybe had nothing to do with the bee’s waggle dance.In order to further explore the functions of GB51125,the expression of GB51125 in honeybee’s different parts and tissues was compared in this study.The results indicated that:(1)the expression level of GB51125 in head of foragers was significantly higher than those in thorax and abdomen,no matter whether the age in days of foragers was the same;(2)the tissues related to collection in the head included cephalic salivary gland and brain,but the relative expression of the gene in the brain was significantly higher than that in cephalic salivary gland.All above results indicate that this gene generally plays a role via the brain;as the brain of honeybee can regulate honeybee’s behaviors and this gene is also related to the waggle dance,GB51125 may be an important gene to regulate the waggle dance. |
