Global Landscape of Alternative Splicing in Tree Peony Floral Organs and the Mechanism Underlying PsuSEP3L ‐ and PsuSEP3S ‐Mediated Flower Type Diversification

Summary Statement We systematically characterized alternative splicing (AS) events in the tree peony cultivar ‘Zhao Fen’, with a focus on the types, distribution, number, and domains of AS across various floral organs. The AS of MADS‐box genes plays a crucial role in the formation of distinct floral organs in tree peony with different flower types. We further cloned the two AS variants of PsuSEP3 , namely PsuSEP3L and PsuSEP3S , and elucidated that PsuSEP3L and PsuSEP3S have distinct functions and differentially affect the formation of floral organs in the tree peony cultivar ‘Zhao Fen’ through interacting with PsuAP1 and PsuAG .