Isolation And Expression Pattern Analysis Of MADS-box Genes Related To Flower Development Of Flowering Plum (Prunus Triloba)

Flowering plum(Prunus triloba), an important ornamental plant in the north of China, is an octaploid species belonging to Prunus genus with high-degree double flowers and various flower types. MADS-box genes have been proved to play important roles in specifying flower organs and the other biological processes. Thus the classic ABC(D)E model was proposed and detailed. However, there is rare researches about p. triloba flower development and the roles of MADS-box genes in identifying flower organs of P. triloba are still unclear. Thus this papar referred to the researches of MADS-box genes of Arabidopsis thaliana, Antirrhinum majus, P. mume and P. persica to clon 10 MADS-box genes related to floral development from three P. triloba cultivars,’Dahua Zi’,’Fuban Tiaozhi’and’Hanyan’, and detected the expression patterns of PtAP1,PtAP3,PtPI and PtAG with qRT-PCR. Additionally, this research selected a suitable reference gene for the qRT-PCR of flower development of different P. triloba cultivars from nine candidate genes. Here are main results:1.11 Type Ⅱ MADS-box genes were obtained from three P. triloba, inculding three A class genes (PtAPl, PtFUL1 and PtFUL2), three B class genes (PtAP3, PtAP3-2 and PtPI), one C function gene (PtAG) and four SEP subfamily genes(PtSEP2, PtSEP3, PtSEP3-2 and PtSEP4). Analysing the structure of those 10 genes suggested that each gene may have happened silent mumtation, missense mutation, nucleic acid deletions or insertions. Thus evey gene may own more than at least one allelic gene, and nucleic acid deletions or insertions could lead to changes of gene structure.2. Nine candidate genes, Pt18sRNA, PtTEF2, PtACTIN, PtGAPDH, PtEF 1-α-1, PtEF 1-α-2, PtEF 1-α-3, PtRPL13 and PtRP II were chosen from references about relatives of P. triloba. Results indicated that PtRPL13 is the most suitable refrence gene for the studies about the flower development of P. triloba.3.Analysis of expression patterns of PtAP1, PtPI, PtAP3 and PtAG expalined the different flower development models of three P. triloba varieties. Ectopic expressions of PtAP3 and PtPI could not change phenotype of ’Dahua Zi’. Double-flower of ’Fuban Tiaozhi’ may be caused by the ectopic expressions of PtAPl, PtAP3,PtAG and the extension of PtPI, and the double-flower of ’Hanyan’ may be the consequence of the extension of PtAPl, PtPI, PtAG and the ectopic expression of PtAP3, which is different from’Fuban Tiaozhi’.This research was the first time to explain the molecular mechanisms of P. triloba flower development, these results above indicated that MADS-box genes play important roles in the flower development P. triloba, which may provide theoretical directions for P. triloba breeding.