Flavonoid extracts from chrysanthemum with appropriate anthocyanins turn blue when exposed to iron ions

Although some species that accumulate only cyanidin(Cy)in nature can produce blue flowers through iron ions,there has been no evidence of blue chrysanthemums being generated in this manner.This study revealed that flavonoid extracts from the ray florets of the chrysanthemum cultivar‘Wandai Fengguang’turned blue when exposed to Fe^(3+).Samples that could turn blue were labeled as CB(Cy-determined blue flowers),while samples that did not turn blue were labeled as CN(Cy-determined non-blue flowers).After a series of experiments,a stable screening system was established using flavonoid extracts containing NaAc buffer at pH 5.5 and a total anthocyanin concentration(TAC)of 30 μmol·L^(-1),and the addition of Fe^(3+)from 0 to 0.25 μmol·L^(-1)allowed for the selection of five CB samples from 39 chrysanthemum cultivars.All five CB samples exhibited flower color phenotypes that belonged to Cluster-I with redness(a*)values ranging from 29.03 to 45.99,yellowness(b*)values from-11.31 to 3.77,and brightness(L*)values from 29.07 to 45.99.Additionally,the ratio of TAC to total luteolin concentration(TLC)was found to be a critical factor for distinguishing between CB and CN samples.To realize the desired blue hue in the flavonoid extracts with the participation of Fe^(3+),a TAC to TLC ratio of 2.25 and above is required.Moreover,the protoplasts and ray florets of CB samples that turned blue with the involvement of Fe^(2+)showed great potential for cultivating blue chrysanthemums through ferric-anthocyanin chelate.Overall,this study reveals that blue flowers can be cultivated through the increase in the iron ion concentration,combined with the accumulation of Cy.

High-density genetic map construction and identification of loci controlling flower-type traits in Chrysanthemum(Chrysanthemum×morifolium Ramat.)

Flower type is an important and extremely complicated trait of chrysanthemum.The corolla tube merged degree(CTMD)and the relative number of ray florets(RNRF)are the two key factors affecting chrysanthemum flower type.However,few reports have clarified the inheritance of these two complex traits,which limits directed breeding for flower-type improvement.In this study,305 F1 hybrids were obtained from two parents with obvious differences in CTMD and RNRF performance.Using specific-locus amplified fragment sequencing(SLAF-seq)technology,we constructed a high-density genetic linkage map with an average map distance of 0.76 cM.Three major QTLs controlling CTMD and four major QTLs underlying RNRF were repeatedly detected in the 2 years.Moreover,the synteny between the genetic map and other Compositae species was investigated,and weak collinearity was observed.In QTL regions with a high degree of genomic collinearity,eight annotated genes were probed in the Helianthus annuus L.and Lactuca sativa L.var.ramosa Hort.genomes.Furthermore,20 and 11 unigenes were identified via BLAST searches between the SNP markers of the QTL regions and the C.vestitum and C.lavandulifolium transcriptomes,respectively.These results lay a foundation for molecular marker-assisted breeding and candidate gene exploration in chrysanthemum without a reference assembly.

Application of Real-time Fluorescent Quantitative PCR in Studies on Plants

Real-Lime fluorescent quantitative PCR is a method for quantitative analysis of gene expression developed in recent years, which has been widely used in various fields such as basic scientific research, clinical diagnosis, disease study, drug research and development since its appearance. It starts relatively late in study on plants, but has already been used for analysis of gene expression in plants and gene identification of exogenous genes. The principles or advantages and dis- advantages of real-time fluorescent quantitative PCR, or its potential problems and condition optimizations in tests were introduced in this study, and then the appli- cation and prospect of real-time fluorescent quantitative PCR in study on plants were also been discussed.

Tobacco Rattle Virus-induced Phytoene Desaturase (PDS) Silencing in Centaurea cyanus

Virus-induced gene silencing(VIGS)is a genetic tool used to assess gene function.Tobacco rattle virus(TRV)is a VIGS vector commonly used to induce endogenous gene silencing in plants.However,there is no VIGS system established for Centaurea spp.We evaluated the effectiveness of a TRV-based VIGS system using phytoene desaturase(PDS)as a reporter gene in Centaurea cyanus.Three methods including pressure-,vacuum-and apical meristem-infiltrationwere tested to infect C.cyanus seedlings.Photobleached leaveswere only obtained using apicalmeristem-infiltration after a 14 d treatment.The CcPDS transcripts in photobleached leaves were significantly reduced compared with that in green leaves treated with empty TRV.Four C.cyanus cultivars were tested to detect their VIGS responses,and‘Dwarf Tom Pouce Blue’was the most sensitive.The agro-infiltration condition was optimized by screening for the optimal seedling stage as well as the optimum Agrobacterium density for efficient silencing.Seedlings with four true leaves and infiltration with an Agrobacterium density of OD_(600)0.5 were optimal conditions to obtain more photobleached leaves and more intense photobleached phenotype.The results demonstrated the feasibility of TRV-based VIGS for functional analysis of genes in C.cyanus.

Genotype Screening of Recipient Resources with High Regeneration and Transformation Efficiency in Chrysanthemum

Genetic transformation is one of the key steps in the molecular breeding of chrysanthemum,which relies on an optimal regeneration and transformation system.However,the regeneration system of different chrysanthemum cultivars varies,and the regeneration time of most cultivars is long.To screen cultivars with highly efficient regeneration,leaves and shoot tip thin cell layers(tTCL)from eight chrysanthemum cultivars with different flower colors and flower types were cultured on Murashige and Skoog media(MS)supplemented with 1.0-5.0 mg L^(−1)6-benzylaminopurine(6-BA)and 0.1-1.0 mg L^(−1)α-naphthaleneacetic(NAA).The results showed that the most efficient regeneration media were MS+6-BA 1.0 mg L^(−1)+NAA 0.5 mg L^(−1)for leaf explants and MS+6-BA 5.0 mg L^(−1)+NAA 0.1 mg L^(−1)for tTCL explants.Subsequently,another 13 chrysanthemum cultivars were screened by using the media,and finally,three cultivars with high regeneration efficiency were obtained from 21 cultivars.Among these,C1 had the highest regeneration efficiency:the regeneration rate of leaf explants reached 80.0%after 42 days of culture,and the regeneration rate of tTCL explants reached 100%after 31 days of culture.Furthermore,we also established the transformation system for C1 as follows:preculturing for one day,infecting with Agrobacterium suspension(OD_(600)=0.6)for 10 min,and cultivating in the regeneration medium with 350 mg L^(−1)carbenicillin and 10 mg L^(−1)kanamycin,thus ultimately achieving a transformation rate of 4.0%.In this study,a new chrysanthemum cultivar with an efficient regeneration and transformation system was screened,which is beneficial to enrich the flower color of chrysanthemum transgenic plant recipients and to the functional research of flower color or type-related genes.

中国传统大菊叶片形态的数量化定义与分类

中国传统大菊品种叶片形态变异丰富,然而至今仍未对其进行科学的定义和分类,无法有效利用这些形态性状进行品种鉴定和叶形遗传解析。利用数量化分析方法对植物形态进行定义和分类,是植物性状遗传解析的前提。对436个中国传统大菊品种的24个叶形性状进行重新定义及观测,通过相关性分析确定了8个相对独立的性状,用变异系数及主成分分析等数量化分析方法筛选出叶长/叶宽、叶片最宽处所在位置/叶长、右下裂片长/右下叶脉长、右下裂片长/右下裂片宽及叶柄长/全叶长5个相对独立且关键的叶部性状。利用这5个性状,通过Q聚类分析,最终将菊花(Chrysanthemum×morifolium)叶片分为16种叶型。研究结果为菊花品种鉴定提供了有效的叶部评价标准,并建立了中国传统菊花品种叶片数量化定义和分类体系,也为观赏植物复杂性状的解析提供了新方法。