Preliminary Study on the Mechanism of Flower Color Variation in White Mutants of Anthurium andeaeanum

[Objectives] This study was conducted to explore the physiological mechanism of flower color variation in the white mutants of Anthurium andeaeanum. [Methods] The seven white mutants of 'Alabama' and 'Turenza' were used as materials to analyze the pigment types, flavonoid types and content and anthocyanin content in the wild type and mutants. [Results] The white spathe mainly contained flavonoids, flavonols, dihydroflavonols and dihydroflavonols; the white mutants of 'Alabama' had a higher total flavonoid content than the wild type, while the white mutants of 'Turenza' showed an opposite trend; and the spathe of the wild type had the highest anthocyanin content, and the pink part of the two-color mutant or the spathe of the binary color mutant contained trace anthocyanins, while no anthocyanins were detected in the white part of the mutants. [Conclusions] The main cause of the white mutants of A. andeaeanum is related to anthocyanin metabolism.

Effects of Paclobutrazol on Physiological Parameters of Dahlia under Heat Stress

[Objectives] This study was conducted to investigate the effect of paclobutrazol （PBZ） on heat tolerance of dahlia.[Methods] A dahlia variety Danbanhuang was selected as the experimental material in this study. After 100, 200, 300 or 400 mg/L paclobutrazol was sprayed evenly to the leaves of dahlia seedlings, they were cultured in an incubator at high temperature （35 ℃/30 ℃, day/night） for two days, and then transferred to an incubator at normal temperature （25 ℃/20 ℃, day/night）. The physiological and biochemical parameters of the dahlia seedlings were measured before exposure to high temperature （D0）, after exposure to high temperature for two days （D2） and exposure to normal temperature for one day （R1）.[Results] Compared to the negative control, foliar application of paclobutrazol decreased the content of MDA, increased the contents of chlorophyll, proline, soluble protein, and the activity of SOD, POD and CAT in dahlia plants under heat stress. The contents of MDA, soluble protein and proline in PBZ treated dahlia plants increased when they were subject to high temperature stress （35 ℃/30 ℃, day/night）, and then decreased when the temperature returned to normal （25 ℃/20 ℃, day/night）, and CAT activity decreased at high temperature, and then increased at normal temperature, while the activity of SOD and POD kept rising during the entire experimental period.[Conclusions] Foliar application of paclobutrazol can alleviate the adverse effect caused by high temperature to dahlia plants, and the experimental data provide a theoretical basis for the application of paclobutrazol in dahlia cultivation in South China.

Artificial stepwise light harvesting system in water constructed by quadruple hydrogen bonding supramolecular polymeric nanoparticles

Stepwise energy transfer is ubiquitous in natural photosynthesis,which greatly promotes the widespread use of solar energy.Herein,we constructed a supramolecular light harvesting system based on sequential energy transfer through the hierarchical self-assembly of M,which contains a cyanostilbene core flanked by two ureidopyrimidinone motifs,endowing itself with both aggregation-induced emission behavior and quadruple hydrogen bonding ability.The monomer M can self-assemble into hydrogen bonded polymers and then form supramolecular polymeric nanoparticles in water through a mini-emulsion process.The nanoparticles were further utilized to encapsulate the relay acceptor ESY and the final acceptor NDI to form a two-step FRET system.Tunable fluorescence including a white-light emission was successfully achieved.Our work not only shows a desirable way for the fabrication of efficient two-step light harvesting systems,but also shows great potential in tunable photoluminescent nanomaterials.

Recent advances in two-step energy transfer light-harvesting systems driven by non-covalent self-assembly

Sequential energy transfer is ubiquitous in natural light-harvesting systems(LHSs),which greatly promotes the exploitation of light energy.The LHSs in nature are sophisticated supramolecular assemblies of chlorophyll molecules that carry out efficient light harvesting through cascade energy transfer process.Inspired by nature,scientists have paid much attention to fabricate stepwise LHSs based on assorted supramolecular scaffolds in recent years.Light-harvesting antennas and energy acceptors can be accommodated in particular scaffolds,which offer great convenience for energy transfer between them.These systems not only further mimic photosynthesis,but also demonstrate many potential applications,such as photocatalysis,tunable luminescence,and information encryption,etc.In this review article,aiming at offering a practical guide to this emerging research field,the introduction of construction strategies towards sequential LHSs will be presented.Different scaffolds are classified and highlighted,including host-guest assemblies,metal-coordination assemblies,as well as bio-macromolecular and other supramolecular scaffolds.

Electrofluorochromic imaging analysis of dopamine release from living PC12 cells with bipolar nanoelectrodes array

The coupling of bipolar electrode(BPE)arrays and electrofluorochromic(EFC)imaging has exhibited great abilities in bioanalysis.However,the imaging resolution and analytical performance are hampered by the large size of the electrode and the rapid diffusion of EFC molecules on the electrode surface.Here,to address the challenges,bipolar nanoelectrodes(BPn E)array and in situ immobilization strategy of EFC molecules were proposed.Anodized aluminum oxide(AAO)template-assisted Au nanoelectrodes array with high density was fabricated as BPn E array for high spatial imaging resolution.By electrically polymerizing EFC molecules on the surface of single Au nanoelectrode,the rapid diffusion of EFC molecules on the electrode surface was not only avoided,but also realizing electrofluorescent imaging on an individual nanoelectrode.Using dopamine(DA)released from living PC12 cells as a model,the proposed strategy exhibited an ultra-high sensitivity for DA analysis with a detection limit of 0.45 nmol/L and the DA release amount from a single cell was calculated to be 0.13 pmol/L.Moreover,the dynamic change of DA release under the drug stimulation from living PC12 cells could also be monitored.

Study on High-frequency Callus Induction From Aseptic Plantlets of Anthuium andraeanum

[Objectives]This study was conducted to improve the efficiency of callus induction and redifferentiation,and construct high-frequency plant regeneration techniques of tissue culture in Anthuium andraeanum.[Methods]The effects of different genotypes,explant types and hormonal conditions on callus induction and re-differentiation of A.andraeanum were studied by using the aseptic A.andraeanum test-tube plantlets as test materials.[Results]Among the four kinds of aseptic A.andraeanum plantlets,the callus induction using stem segments with leaves was the best,followed by stem segments and leaves,and the petioles were the worst;among the six A.andraeanum varieties tested,the callus production rates of four varieties reached 100%;and the callus differentiation rate reached 93.3%-100%through the organogenesis pathway,and the suitable differentiation medium was 1/2MS+ZT 0.5 mg/L+2,4-D 0.1 mg/L.[Conclusions]The research results provide a new experimental basis for optimizing the technical system of A.andraeanum rapid propagation.

High-quality Fagopyrum esculentum genome provides insights into the flavonoid accumulation among different tissues and self-incompatibility

Common buckwheat(Fagopyrum esculentum)and Tartary buckwheat(Fagopyrum tataricum),the two most widely cultivated buckwheat species,differ greatly in flavonoid content and reproductive mode.Here,we report the first high-quality and chromosome-level genome assembly of common buckwheat with 1.2 Gb.Comparative genomic analysis revealed that common buckwheat underwent a burst of long terminal repeat retrotransposons insertion accompanied by numerous large chromosome rearrangements after divergence from Tartary buckwheat.Moreover,multiple gene families involved in stress tolerance and flavonoid biosynthesis such as multidrug and toxic compound extrusion(MATE)and chalcone synthase(CHS)underwent significant expansion in buckwheat,especially in common buckwheat.Integrated multi-omics analysis identified high expression of catechin biosynthesis-related genes in flower and seed in common buckwheat and high expression of rutin biosynthesis-related genes in seed in Tartary buckwheat as being important for the differences in flavonoid type and content between these buckwheat species.We also identified a candidate key rutindegrading enzyme gene(Ft8.2377)that was highly expressed in Tartary buckwheat seed.In addition,we identified a haplotype-resolved candidate locus containing many genes reportedly associated with the development of flower and pollen,which was potentially related to self-incompatibility in common buckwheat.Our study provides important resources facilitating future functional genomics-related research of flavonoid biosynthesis and selfincompatibility in buckwheat.

毛竹扩张对杉木林土壤细菌群落的影响

土壤微生物是森林生态系统的重要组成部分,毛竹(Phyllostachysedulis)扩张使植被类型发生改变,进而对土壤微生物群落产生影响。为揭示毛竹向杉木(Cunninghamialanceolata)林扩张过程中对土壤细菌群落的影响。本文在浙江省杭州市临安区於潜镇南山村,以杉木纯林(s)为对照,选取毛竹杉木混交林(h)、毛竹纯林(m)两种林型,通过高通量测序技术探究毛竹扩张对杉木林土壤细菌群落的影响。结果表明:毛竹扩张导致杉木林土壤细菌群落α多样性降低,与杉木林相比,混交林地细菌多样性及丰富度分别降低了2.4%、8.6%,但无显著差异;毛竹林分别降低了5.9%、16%,且差异显著(P <0.05)。毛竹扩张杉木林后,改变了土壤细菌菌群的相对多度;杉木林中变形菌门、Unassigned和疣微菌门的相对多度最高,分别占32.39%、3.7%、3.2%;毛竹林中酸杆菌门和拟杆菌门的相对多度最高,分别占45.05%、5.19%;混交林中浮霉状菌门、放线菌门和绿弯菌门的相对多度最高,分别占7.51%、6.79%、5.12%。毛竹扩张形成混交林后,浮霉状菌门、放线菌门的相对多度显著上升(P <0.05),分别增加了3.12%、2.71%,而迷踪菌门和芽单胞菌门的相对多度显著下降(P <0.05),分别减少了0.43%、0.36%;奇古菌门相对多度显著下降(P <0.05)。β多样性分析结果显示,毛竹扩张对杉木林土壤细菌群落结构产生显著影响(P <0.05),毛竹林与竹杉混交林的土壤细菌结构较为接近,两者与杉木林细菌群落集聚距离较远。LEfSe分析显示硝化螺菌属(Nitrospira)、芽单胞菌科和分枝杆菌属(Mycobacterium)的相对多度变化显著,可作为毛竹扩张杉木林土壤细菌群落结构变化的指示种。土壤NH4+可能是引起细菌群落变化的主要土壤环境因子。这些结果说明毛竹向杉木林扩张可引起林地土壤细菌群落发生改变,这为了解毛竹扩张对土壤碳氮等元素循环、扩张机制及扩张调控提供了基础数据。

重新认识土壤有机质

以腐殖质为主要成分的土壤有机质占土壤固相组成的2%~8%,是土壤中养分元素的承载者、微生物活动的驱动者以及矿质转化的调节者,对于土壤功能的发挥起着关键作用.早在19世纪初,德国土壤学者D?bereiner[1]和Sprengel[2]就提出“humic acids”概念.有学者利用碱提取和酸沉淀的方法将土壤有机质分成富里酸、胡敏酸以及高度缩合、惰性的胡敏素等不同组分[3-4].

The Chromosome-Level Genome Sequence of the Autotetraploid Alfalfa and Resequencing of Core Germplasms Provide Genomic Resources for Alfalfa Research

Alfalfa(Medicago sativa)is one of the most important forage crops in the world;however,its molecular genetics and breeding research are hindered due to the lack of a high-quality reference genome.Here,we report a de novo assembled 816-Mb high-quality,chromosome-level haploid genome sequence for‘Zhongmu No.1’alfalfa,a heterozygous autotetraploid.The contig N50 is 3.92 Mb,and 49165 genes are annotated in the genome.The alfalfa genome is estimated to have diverged from M.truncatula approximately 8 million years ago.Genomic population analysis of 162 alfalfa accessions revealed high genetic diversity,weak population structure,and extensive gene flow from wild to cultivated alfalfa.Genome-wide association studies identified many candidate genes associated with important agronomic traits.Furthermore,we showed that MsFTa2,a Flowering Locus T homolog,whose expression is upregulated in salt-resistant germplasms,may be associated with fall dormancy and salt resistance.Taken together,these genomic resources will facilitate alfalfa genetic research and agronomic improvement.

Analysis of genetic architecture and favorable allele usage of agronomic traits in a large collection of Chinese rice accessions

Genotyping and phenotyping large natural populations provide opportunities for population genomic analysis and genome-wide association studies(GWAS). Several rice populations have been re-sequenced in the past decade;however, many major Chinese rice cultivars were not included in these studies. Here, we report large-scale genomic and phenotypic datasets for a collection mainly comprised of 1,275 rice accessions of widely planted cultivars and parental hybrid rice lines from China. The population was divided into three indica/Xian and three japonica/Geng phylogenetic subgroups that correlate strongly with their geographic or breeding origins. We acquired a total of 146 phenotypic datasets for 29 agronomic traits under multi-environments for different subpopulations. With GWAS, we identified a total of 143 significant association loci, including three newly identified candidate genes or alleles that control heading date or amylose content. Our genotypic analysis of agronomically important genes in the population revealed that many favorable alleles are underused in elite accessions, suggesting they may be used to provide improvements in future breeding efforts. Our study provides useful resources for rice genetics research and breeding.

生物信息学分析方法Ⅰ:全基因组关联分析概述

全基因组关联分析(GWAS)是动植物复杂性状相关基因定位的常用手段。高通量基因分型技术的应用极大地推动了GWAS的发展。在植物中,利用GWAS不仅能够以较高的分辨率在全基因组水平鉴定出各种自然群体特定性状相关的基因或区间,而且可揭示表型变异的遗传架构全景图。目前,人们利用GWAS分析方法已在拟南芥(Arabidopsis thaliana)、水稻(Oryza sativa)、小麦(Triticum aestivum)、玉米(Zea mays)和大豆(Glycine max)等模式植物和重要农作物品系中发掘出与各种性状显著相关的数量性状座位(QTL)及其候选基因位点,阐明了这些性状的遗传基础,并为揭示这些性状背后的分子机理提供候选基因,也为作物高产优质品种的选育提供了理论依据。该文对GWAS的方法、影响因素及数据分析流程进行了详细描述,以期为相关研究提供参考。

Genomic atlases of introgression and differentiation reveal breeding footprints in Chinese cultivated rice

The long history of cultivation and breeding has left a variety of footprints in the genomes of Asian cultivated rice(Oryza sativa L.).In this study,we focus on two types of genomic footprints,introgression and differentiation,in a population of more than 1200 Chinese rice accessions.We found that a Xian/indica and a temperate Geng/japonica accession respectively contained an average of 19.3-Mb and 6.8-Mb alien introgressed chromosomal segments,of which many contained functional sequence variants,quantitative trait loci,or genes controlling flowering,grain,and resistance traits.Notably,we found most introgressions,including the known heterotic loci Hd3 a and TAC1,were distributed differentially between the female and male parents of three-line indica hybrid rice,indicating their potential contribution to heterosis.We also found many differentiated regions between subgroups within a subpopulation contained agronomically important loci,such as DTH7,Hd1 for heading date,and qCT7 for cold tolerance,providing new candidates for studying local adaptation or heterosis.Tracing these footprints allows us to better understand the genetic exchange or differentiation underlying agronomic traits in modern Chinese rice cultivars.These findings also provide potential targets for rice genetic research and breeding.