Study On Bees Visiting Behavior On Pear And Identification And Expression Characterization Of Its Foraging-related Genes

When Bees pollinate for the target crop, they can meet crops which are not preference for.Pear belongs to one of crops which bees don't like visiting. This may be related to pear flower color, aroma and pear flower pollen nutrition value. Therefore inducing bees for pear tree pollination is important and urgent. By field experiment, it is studied that other plants of pear blossom, honeybee foraging behavior on pear flower and other plants of pear blossom, and the composition of nectar and pollen of these plants, so as to searching for the reason that honeybee do not prefer to foraging pear flower. On this basis, we can make use of inducing inside colony and outside of colony to filtering bee attraction suitable for pear pollination. At last, we clone two foraging behavior-related genes Acfor and Acmvl of Apis cerana and have a sequence analysis for understanding the mechanism of honeybee foraging behavior. In this paper, the author has explored the reason why the honeybees have not a preference for pear tree from multi-level. It can provide theoretical data for induction bees pollinate for pear later.By the above study, we obtain the following results:(1) We inspect plant species having same flowering time with pear bloosm in Taigu county, jinzhong City and Yanhu district, Yuncheng City, Shanxi province. It is found that there are Brassica campestris Rape, Paulownia spp., Herba Taraxaci, especially Brassica campestris Rape.(2) We observe honeybee foraging behavior on Pyrus bretshneideri Dangshan pear, Pyrus communis Bartlett pear, Pyrus bretschneideri Huang pear, Pyrus bretschneideri Xuehua pear, Pyrus bretschneideri Huangguan pear in Taigu County, Jinzhong City and Yanhu district, Yuncheng City. The results are showed honeybee has different enthusiasm among these pear trees. At Taigu County, Jinzhong City, Xuehua pear had the highest visiting frequency of bees, Dangshan pear better, Huangguan pear worst. At Yanhu district, Yuncheng City, honeybee visit Bartlett pear best, Dangshan pear better, Huang pear worst.By analyzing the number and the frequency of honeybee visiting Rape and Dangshan pear, we conclude that honeybee pollination enthusiasm for Rape is higher than Dangshan pear. This further validated honeybee pollination effect is lower for pear trees when there were competitive flowers.(3) In the nectar of five pear species, glucose content is the highest, fructose content lower, sugar content lowest. Among them, the DangShan pear showed the highest content of fructose, glucose and sucrose. Fructose and glucose content of Xuehua pear nectar are all the lowest. The sucrose content of Bartlett pear is the lowest. At Taigu County, Jinzhong City, bees preferring for Dangshan pear shows that bees prefer for plants nectar of high sugar content. At Yanhu district, Yuncheng City, the bees prefer to visit the Bartlett pear, which shows that bees also like to visit the low sucrose content of plant. Maltose is not detected in all samples.Analysis on amino components and proportion of the different species and rape pollen shows that cystine and lysine in Bartlett pear pollen are quite different from other pear species. It shows that there is significant difference on arginine between Dangshan pear and Rape pollen, other seventeen amino acids content are the same. It is inferred that bees prefer for plants which pollen has higher cysteine, lower lysine and arginine content.(4) Some methods include feeding colonies with pear syrup, gallic acid, arginine, lysine, methionine and 8-Br-cGMP, and hanging juvenile hormone analogue ZR-512, brood gland pheromone (BP), and queen mandibular glands pheromone (QMP). The results show that a significant difference(P<0.05) is seen between pear pollen load weight of hanging QMP and the control group. The QMP group shows the best effect, followed closely by 8-Br-cGMP groups. However, BP group shows the best efficacy in terms of pear pollen in the percentage of total pollen and the percentage of foraging bees on pear flower in foraging bees, followed by QMP and lysine groups. Pear pollen in the percentage of total pollen of the other treatment groups is higher than the control except pear syrup and methionine in all day. It is inferred that the effect of hanging pheromone groups in colony to improve honeybee foraging is better than feeding groups, BP group is the best.On the other hand, we spray the fengweimei, hang the queen pheromone and polynate on pear flowers. It turns out all of these methods could improve the bees visiting frequency, number and foraging enthusiasm. The effect of bee activity enhancement is best.(5) We get the whole cDNA sequences of Acfor and Acmvl by the method of RT-PCR and RACE. Acfor gene cDNA span is 3096 bp and contains ORF 2220bp, coded 740 amino acids. Acmvl gene cDNA span is 2130 bp and contains ORF 1764bp, coded 588 amino acids. Making use of a variety of biological software, we have done Acfor and Acmvl bioinformatics analysis. The molecular weights of the two sequences protein are respectively 83.57KD and 65.86 KD, water-soluble protein, stable character. Acfor is neither membrane protein nor secreted protein, which may be located in the organelles matrix or cytoplasmic matrixand. It has 39 phosphorylation sites. In the secondary structure of Acfor, it has crimp ring (about 50.34%), followed by alpha helix (about 31.26%), the small number of extended chain (18.40%). Acmvl have 12 times transmembrane domain and14 phosphorylation sites. It belongs to the membrane protein, can carry out material across the plasma membrane. In the secondary structure dominant of Acmvl, it has alpha helix (about 61.84%), followed by crimp ring (about 36.12%), the number of extended chain minimum (< 5%).(6) The homologous sequences of Acfor and Acmvl gene have been found in hymenoptera by BLAST. The result of multiple sequence alignment show Acfor had higher similarity (>81%) with its orthologous gene in hymenoptera, among them with the highest similarity Amfor at 100%, with similarity Affor lowest, at 81.7%. Acmvl have higher similarity (>70%) with its orthologous gene in hymenoptera, among them with Amfor and Adfor has the highest similarity, at 98.5%, with similarity Nvmvl lowest,70.9%.(7) Expression profiles of mRNA at different developmental stages in head of these two genes were examined by qRT-PCR. The results reveal that the Acfor and Acmvl transcripts are expressed both in worker head. The temporal expression patterns of the two genes are similar. The expression levels are relative high at Id,20d,35d for two genes and reach their highest level around 25 d.In conclusion, we investigate the bees visiting behavior in pear blossom, inducing bees foraging pear flower and explain the bees foraging behavior on molecular level. It provides an important scientific basis for investigating the foraging behavior mechanism.