Cell number explains the intraspecific spur-length variation in an Aquilegia species

作     者：Zhi-Li Zhou Yuan-Wen Duan Yan Luo Yong-Ping Yang Zhi-Qiang Zhang 

作者机构：Institute of Tibetan Plateau Research at KunmingKunming Institute of BotanyChinese Academy of SciencesKunming650201China University of Chinese Academy of SciencesBeijing 100049China Gardening and Horticulture DepartmentXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMengla666303China Laboratory of Ecology and Evolutionary BiologyYunnan UniversityKunming650091China 

出 版 物：《Plant Diversity》 (植物多样性（英文版）)

年 卷 期：2019年第41卷第5期

页      面：307-314页

核心收录：

学科分类：0710[理学-生物学] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 1002[医学-临床医学] 100214[医学-肿瘤学] 0901[农学-作物学] 0902[农学-园艺学] 10[医学] 0713[理学-生态学] 

基　　金：financially supported by National Natural Science Foundation of China (31760104  41461014  31460040  and 31870183) 

主　　题：Aquilegia rockii Cell number Columbine Floral polymorphism Intraspecific variation Nectar spur 

摘      要：Variations of nectar spur length allow pollinators to utilize resources in novel ways,leading to the different selective pressures on spurs and allowing taxa to diversify.However,the mechanisms underlying spur length variation remain unclear.Interspecific comparisons of spur length suggest that both cell division and anisotropic expansion could explain the changes of spur length,and that hormone-related genes contribute to the process of spur formation.In contrast,little is known about intraspecific spur length variation.In Aquilegia rockii,spur length varies strikingly,ranging from 1 mm to 18 mm.To examine the potential mechanisms underlying spur length variation in A.rockii,we observed cell morphology and analyzed RNA-seq of short-and long-spurred flowers.Scanning electron microscopy revealed that at two positions on spurs there were no differences in either cell density or cell anisotropy between short-and long-spurred flowers,suggesting that in A.rockii changes in cell number may explain variations in spur length.In addition,we screened transcriptomes of short-and long-spurred flowers for differentially expressed genes;this screen identified several genes linked to cell division(e.g.,F-box,CDKB2-2,and LST8),a finding which is consistent with our analysis of the cellular morphology of spurs.However,we did not find any highly expressed genes involved in the hormone pathway in long-spurred flowers.In contrast to previous hypotheses that anisotropic cell expansion leads to interspecific spur variation in Aquilegia,our results suggest that cell number changes and related genes are mainly responsible for spur length variations of A.rockii.Furthermore,the underlying mechanisms of similar floral traits in morphology may be quite different,enriching our understanding of the mechanisms of flower diversity in angiosperms.