The genetic basis of plant shoot branching and the hormonal,metabolic and environmental regulation
Plants have evolved diverse architectures for adapting to the changing environment.Shoot branching is one part of plant architecture,and is closely related to the formation of product organs.On the other hand,changes in the allocation of photosynthates as a result of shoot branching also have large impacts on crop yield and quality.The for-mation of lateral branch is determined by several stages including the initiation of axillary meristem,the activation of lateral buds,and the sustained growth of lateral buds.These developmental processes are controlled by genetic,hor-monal,metabolic and environmental regulation.In this review,we summarized how the initiation of axillary meristem and activation of lateral buds are controlled,including the critical transcription factors and their action modes,the function and signaling pathway of different plant hormones and their interactions,and the mechanisms by which sugar and light signals impinge on the hormonal signaling network to regulate shoot branching.Finally,we prospected the future research on the roles of circadian clock and epigenetic modifications in shoot branching,and the technologies of improving crop architecture by using gene editing and environmental control.