Abstract: The function gene MwAG as a key transcription factor that plays crucial roles in the development of Magnolia wufengensis by regulating the development of the stamen and carpel. Semi-quantitative RT-PCR, Northern blot and quantitative RT-PCR methods were used to identify the spatial and temporal expression patterns of MwAG in M. wufengensis at several important stages of the morphological differentiation of flower buds. MwAG was expressed specially in the stamen and pistil, with no detectable expression in outer and inner whorls of the perianth and leaves. The expression was highest at the primordium and mature stages of stamen and pistil during morphological differentiation of organs. The expression peaked earlier in the stamen than in the pistil, and the time of expression was the same as with morphological differentiation of the stamen and pistil. At the early stage of the differentiation of flower buds, the expression was low when flower buds had more petal numbers of the same size, and the time of expression was consistent with the development and differentiation of the stamen and pistil in different flower buds (i.e., the more the petal numbers, the later the time of differentiation of stamen and pistil). MwAG may play a crucial role in stamen and carpel development of M. wufengensis.

Key words: Magnolia wufengensis, MwAG gene, flower development, qRT-PCR