B-class floral homeotic gene MapoAPETALA3 may play an important role in the origin and formation of multi-tepals in Magnolia polytepala  

作　　者：Liyong Sun Yao Chen Tangjie Nie Xiaoxia Wan Xuan Zou Zheng Jiang Huilin Zhu Qiang Wei Yaling Wang Shuxian Li Zengfang Yin 

机构地区：[1]Co-Innovation Center for Sustainable Forestry in Southern China,College of Life Sciences,Nanjing Forestry University,Nanjing,Jiangsu 210037,China [2]Co-Innovation Center for Sustainable Forestry in Southern China,College of Forestry,Nanjing Forestry University,Nanjing,Jiangsu 210037,China [3]Bamboo Research Institute,Nanjing Forestry University,Nanjing,Jiangsu 210037,China [4]Xi'an Botanical Garden,Shaanxi Academy of Science,Xi'an,Shaanxi 710061,China

出　　处：《Horticultural Plant Journal》2025年第2期891-905,共15页园艺学报(英文版)

基　　金：supported by grants from the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX19_1080);A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD);the Doctorate Fellowship Foundation of Nanjing Forestry University。

摘　　要：In angiosperms,floral architecture diversity reflects its significance in exploring plant evolution.Magnolia polytepala,an endemic and ancient species in China,possesses a unique multi-tepal trait.Notably,the origin and formation of these multi-tepals are poorly understood.In this study,we investigated the origin and formation of multi-tepals from the inner floral whorl and elucidated the underlying molecular regulatory mechanisms by combining phenotypic analysis,sequencing,and molecular experiments.We found that the multi-tepals exhibited morpho-anatomical characteristics similar to normal tepals but differed from petaloid and normal stamens.The temporal dynamics of a large number of differentially expressed genes(DEGs)involved in multiple signaling(transduction)pathways contributed to multi-tepal primordia initiation during early floral differentiation.In particular,the dynamic expression of MpW OX4,MpCLE41,MpULT1,and MpKN1 might be responsible for floral meristem activation and maintenance,while MpTGA1 and MpEJ2 potentially regulated floral organ initiation.Floral homeotic genes,such as MapoAP3,contributed to subsequent organ identity specialization.We further isolated a nucleus-localized APETALA3 homolog from M.polytepala,terming it the MapoAPETALA3(MapoAP3)gene,which was expressed in almost all vegetative and reproductive tissues.Ectopically expressing MapoAP3 in Arabidopsis resulted in altered phenotypes of rosette leaves,inflorescences,and florets,particularly generating extra petals instead of undergoing homeotic organ conversion.This discovery revealed an additional function of MapoAP3 in regulating organ initiation in addition to its conserved B-function in floral architecture plasticity.In summary,the multi-tepals of M.polytepala originated from the early tepal primordia initiation event rather than stamen petalody.The formation of the multi-tepal trait was attributed to the coordinated regulation of several vital DEGs,with the MapoAP3 gene playing an important role.These results provide additional ins

关 键 词：Magnolia polytepala Doubleflower Transcriptional regulation Organ initiation MapoAP3 

分 类 号：S685.99[农业科学—观赏园艺]