Transcriptome analysis and metabolic profiling reveal the key role of carotenoids in the petal coloration of Liriodendron tulipifera  

作　　者：Zhaodong Hao Siqin Liu Lingfeng Hu Jisen Shi Jinhui Chen 

机构地区：[1]Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education,Co-Innovation Center for Sustainable Forestry in Southern China,Nanjing Forestry University,Nanjing,Jiangsu,China

出　　处：《Horticulture Research》2020年第1期1955-1970,共16页园艺研究（英文）

基　　金：supported by the Key Research and Development Plan of Jiangsu Province(BE2017376);the Foundation of Jiangsu Forestry Bureau(LYKJ[2017]42);the Qinglan Project of Jiangsu Province,and the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).

摘　　要：Liriodendron tulipifera,also known as tuliptree,is a popular ornamental horticultural plant with extraordinary tulipshaped flowers characterized by an orange band near their base.The mechanisms underlying petal band-specific pigmentation during L.tulipifera flower development are unclear.Here,we combined nontargeted and targeted metabolomics and transcriptomics to identify a pathway cascade leading to carotenoid biosynthesis that is specifically activated in the petal band.The comparative analysis of carotenoid metabolites between L.tulipifera and Liriodendron hybrids indicates thatγ-carotene,a rare carotene in plants,is the most likely orange pigment responsible for the coloration of the petal band.Phenotypic and transcriptomic analyses of developing petals reveal that the band area is first predefined by the loss of green color.Later,the band is maintained by locally activating and repressing carotenoid and chlorophyll biosynthesis genes,respectively.Two rate-limiting genes of carotene biosynthesis,carotenoid isomerase(CRTISO)and epsilon lycopene cyclase(ε-LCY),encode the core enzymes responsible for petal band-specific orange pigmentation in L.tulipifera.In particular,a putative additionalε-LCY copy specific to L.tulipifera may contribute to the distinct petal coloration pattern,compared with L.chinense.Taken together,our work provides a first glimpse of the metabolome and transcriptome dynamics in tuliptree flower coloration and provides a valuable resource for flower breeding or metabolic engineering as well as for understanding flower evolution in an early woody angiosperm.

关 键 词：ORANGE ANALYSIS FLOWERS 

分 类 号：S68[农业科学—观赏园艺]