Abstract: Gibberellin,as one of five major plant hormones,plays a key role in flower bud differentiation,inflorescence development,flowering and fruit setting,fruit growth and plant morphogenesis,etc. However,the research on molecular biology of gibberellin in fruit crops compared with field crops differs largely. In order to more effectively and reasonably use gibberellin to regulate fruit and flower development of fruit trees in fruit crops production,it is necessary to study the synthesis of gibberellin and the molecular regulation mechanism of signal transduction pathways. Here,two aspects,the synthesis of gibberellin of fruit crops and gibberellin signaling pathways,are reviewed,focusing on the key enzyme genes in the process of gibberellin synthesis and their localizations,as well as important components of gibberellin signaling pathway such as gibberellin receptor GID1,DELLA protein and so on. The results showed that the expressions of KO,GA2ox and GA20ox in GA synthesis were negatively correlated with the dwarf of fruit trees,while the content of KS was positively correlated with plant height. The male sterility of chestnut was also closely related to the expression of KO and KAO. GAMYB gene and LFY gene play an important role in the reproductive growth of fruit crops,such as flower formation and stamen development. DELLA protein,as a negative regulator in the GA signaling pathway in fruit trees,lead to the formation of dwarf plants,and DELLA protein ubiquitination degradation plays a vital role in the cell cycle,transcription regulation,flower formation,cell signal transduction,and many physiological processes of the fruit crops. This paper aims at providing an important theoretical reference for the modulation of fruit crop growth and development by effectively utilizing gibberellin.

Key words: fruit trees, gibberellin, metabolism, signal transduction