Study On Flower Pigment Composition And Molecular Mechanism Of Color Difference In Narcissus

Narcissus is a perennial,bulbous plant belonging to the genus Narcissus,amaryllidace.Narcissus is widely used for garden landscape,cut flowers and potted plants based on its unique flower shape and outstanding flower color,and is one of the most important commercial bulbous flower in the floricultural industry.Flower color has been regarded as an important character in deciding the horticultural value of narcissus plants.Enriching flower colors is one of the long-term goals of flower Breeders,hence,getting information of narcissus pigment components,formation mechanism of flower color and biological activities of narcissus pigment are important for carrying out molecular breeding programs towards flower colors,and for intensive study,exploitation and utilization of narcissus in the future.In the study,23 narcissus species of different colors were investigated for their pigment components in perianths and coronas,the relationship between flower color and pigment composition,antioxidant and radical scavenging properties of narcissus extracts,molecular basis underlying the color change.Main results were as follows:1.Florescence,flower color and morphological indexes of 23 narcissuses were investigated from 2013 to 2015,results showed that 23 narcissus cultivars owned better flowering continuity,narcissus florescence concentrated distribution in March and early April.The color and shape of perianths and coronas were significantly different among 23 narcissus cultivars.The corona appeared yellow,orange and light pink,while the perianth largely presented white and yellow.The types of corona mainlyconsisted oftrumpet type,larged-cupped type,small-cupped type,split-cupped type and double type.2.Full-bloom stage narcissuses were used as experimental material,and flower color were described by RHSCC(Royal Horticultural Society Color Card)and CIELAB space color system of CIE(International Commission on Illumination),result showed that the classifications of 23 narcissus cultivars were coincident by two classification methods and 23 narcissus cultivars were divided into four categories,white perianth and yellow corona group(Decoy,Pink Charm,Professor Einsteinand Shangnong Wanxia),white perianth and red corona group(Giantic Star,Jack Snipe,Lemon Beauty,Mondragon,Mount Hood,Slim Whitman,Valdrome,Shangnong Dieying and Shangnong Ruhuang),yellow perianth and yellow corona group(Avalon,Marieke,Spell Blinderand Shangnong Zaochun),yellow perianth and orange corona group(Bontan,Delibes,Fortissimo,Pinza,Pinza Mutation and Shangnong Hongying),according to cluster analysis.3.Pigment components in perianths and coronas of 23 narcissus cultivars were analyzed by HPLC-APCI-MS-MS(HighPerformanceLiquidChromatography withatmospheric pressure chemical ionization source & Mass Spectrometer)and UPLC-Q-TOF-MS(Ultra Performance Liquid Chromatography & Quadrupole-Time-of-Flight Mass Spectrometer),the result demonstrated that eleven carotenoids and ninteen flavonols and chlorogenic acid were identified in 23 cultivars.Among these,9-cis-violaxanthin,all-trans-lutein,all-trans-zeaxanthin,all-trans-ɑ-cryptoxanthin,all-trans-β-cryptoxanthin,all-trans-β-carotene,9-cis-β-carotene,all the flavonol glycosides and chlorogenic acid were identified in narcissus for the first time.A multivariate analysis was used to explore the relationship between flower color and pigment composition.It was found that all-trans-violaxanthin and total carotenoid content(TC)were the main factors that affected flower color,which presented positive effects on the value of L* and b*.4.Six narcissus species with high carotenoid and flavonol contents were investigated for their chemical composition,antioxidant and radical scavenging propertie.Among six narcissus species,the perianths of Shangnong Hongying and the corona of Delibes showed excellent antioxidant and radical scavenging propertie,which could be regarded as the origin of antioxidant additive.In addition,these narcissuses were rich in phenolic and flavonoid,especially Shangnong Hongying perianth,andthere was dose-effect relation between antioxidant ability and phenolic and flavonoid contents except Delibes corona.5.Through selective breeding,a bud sport Narcissus ?Shangnong Wanxia‘(WX)was bred through spontaneous mutants from a narcissus cultivar N.?Professor Einstein‘(PE).Most of the biological features of WX,except for flower color,are identical with those of PE.In the study,the flower color,pigment components,pigment contents,carotenoid biosynthetic structural genes PSY,PDS,ZDS,CRTISO,LCYb,LCYe,HYb and flavonol biosynthetic structural genes CHS,CHI,F3 H,F3‘H,FLS were compared between PE and WX during flower development.HPLC-APCI-MS/MS and UPLC-Q-TOF-MS/MS profiles revealed that eleven carotenoids,ten flavonols,and chlorogenic acid were identified in two cultivars.WX coronas accumulated lower amounts of carotenoids than PE during flower development,particularly β-carotene,which was the principal factor led to color variation of WX corona.Lower total flavonol content was present in the WX corona compared with that in PE,which was related to the lower expression levels of CHS,CHI,and FLS,suggesting its role in differences in flower color between the two cultivars.