鸡毛菜(Brassica rapa L.Chinensis Group.)的颜色变化动力学及两种货架期预测方法

实验测定了贮藏在278、283、288、293K四个温度下的鸡毛菜的颜色参数L*、-a*、b*、△E、h*和感官评价,并对L*和△E进行了动力学分析。结果表明,在实验温度范围内,鸡毛菜储藏的温度越低,颜色参数变化越慢。动力学分析显示,零级动力学比一级动力学更适合表现鸡毛菜L*和△E的变化规律。研究还采用Arrhenius方程对颜色变化速率常数k和温度T进行非线性拟合,得到L*和△E活化能Ea分别为82.09kJ/mol和100.26kJ/mol。最后得到依赖于时间、温度和颜色指标的鸡毛菜货架期预测方程(R2>0.95),从中根据不同的L*和△E终点可得到对应的货架期。就本研究而言,假定L*增加12%为终点时,鸡毛菜在四个温度下的预测货架期分别为11.8、5.5、2.6、1.3d。同时,Arrhenius方程与依赖于感官终点的动态颜色终点拟合方程结合预测的货架期曲线与感官寿命曲线则能得到更好的契合(两者绝对差值小于0.6d),两者结合能得到较为全面的货架期预测参数。

Comparison Between a Tetraploid Turnip and Its Diploid Progenitor(Brassica rapa L.):The Adaptation to Salinity Stress

Polyploidy is pursued in plant breeding programs due mainly to its ability to yield larger vegetative or reproductive organs. In controlled growth chamber experiments, a tetraploid turnip （cv. Aijiaohuang, 4n） and its diploid progenitor （cv. Aijiaohuang, 2n） were evaluated for their tolerance to salinity stress via investigations on a group of physiological parameters. The results indicate that the tetraploid turnip exhibit better adaptation to a high concentration salt medium （200 mmol L-1）, as evidenced by a less-affected germination rate and a healthier morphological appearance at the seedling stage. Furthermore, an extension of salinity stress up to a certain period of time at the 5-7-leaf stage shows differences between the tetraploid turnip and its diploid progenitor. The former had a higher K＋/Na＋ ratio in the roots, higher glutathione concentration and antioxidant activities in the leaves, and smaller reductions in photosynthetic capacity in terms of leaf chlorophyll content. Studies on the differences between an autopolyploid and its respective relative, from which the autopolyploid originated, in terms of their tolerance to salinity and/or other abiotic stresses, have remained rather limited. The comparison is interesting due to a homogenous genetic background.

Transformation of Chinese Cabbage(Brassica rapa L. ssp. pekinensis)by Agrobacterium Micro-Injection into Flower Bud

We obtained two lines of Chinese head cabbage(Brassica rapa L. ssp. pekinensis)selfed progenies containing both an anti-sense gene of BcpLH and a gene for resistance to kanamycin by micro-injecting buds of their primary transformants(T0)with Agrobacterium tumefaciens strain LBA4404. 31 positive plants resistant to kanamycien were recovered. Southern blot analysis confirmed the presence of T-DNA in two transgenic plants. One(DHZ-13-1)exhibits the characteristics of out-toward rosette and cauline leaves, and nested flower model in which secondary complete flower developed from the base of the primary ovary and the third flower from the ovary in the secondary flower, and so on, while another(DHZ-6-1)has no phenotype change. ABA and IAA affected the root growth of progeny of DHZ-13-1, but 6-BA was insensitive to hypocotyl growth during its seedling development.

Antioxidant metabolic system and comparative proteomics analysis in winter turnip rape(Brassica rapa L.)under cold stress

Winter turnip rape(Brassica rapa L.)is widely cultivated in winter in Northwest China,however,its cold-tolerant mechanism remains insufficiently understood.In this study,winter turnip rape cultivar Longyou 7,a cold-tolerant variety,was used as material,whose accumulation of H_(2)O_(2) and O_(2)^(·-),antioxidant enzyme activity as well as differences in protein expression based on two-dimensional gel electrophoresis(2-DE)technique under -4℃ stress were analyzed.Results showed that,production of H_(2)O_(2) and O_(2)^(·-) were increased in Longyou 7 leaves,simultaneously,SOD and POD activities were also obviously rosed up,but the activities of CAT and APX were gradually reduced with the temperature.Thirty-six differential protein spots were successfully identified between control and treatments group by using mass spectrometry analysis.Among them,4 differential protein spots were induced under cold stress,and 2 were inhibited at-4℃.Functional analysis found that these identified proteins mainly participated in photosynthesis,carbohydrate metabolism,defense,protein synthesis,enzyme activity,redox and membrane metabolism,respectively.Additionally,13 proteins'function were still unknown.In conclusion,strong antioxidant capacity and cell defense ability might play important roles in Longyou 7 response to cold stress.

Selenium-oxidizing Agrobacterium sp.T3F4 decreases arsenic uptake by Brassica rapa L.under a native polluted soil

Toxic arsenic(As)and trace element selenium(Se)are transformed by microorganisms but their complex interactions in soil-plant systems have not been fully understood.An Asand Se-oxidizing bacterium,Agrobacterium sp.T3F4,was applied to a native seleniferous As-polluted soil to investigate As/Se uptake by the vegetable Brassica rapa L.and As-Se interaction as mediated by strain T3F4.The Se content in the aboveground plants was significantly enhanced by 34.1%,but the As content was significantly decreased by 20.5% in the T3F4-inoculated pot culture compared to the control(P<0.05).Similar result was shown in treatment with additional 5 mg/kg of Se(IV)in soil.In addition,the As contents in roots were significantly decreased by more than 35% under T3F4 or Se(IV)treatments(P<0.05).Analysis of As-Se-bacterium interaction in a soil simulation experiment showed that the bioavailability of Se significantly increased and As was immobilized with the addition of the T3F4strain(P<0.05).Furthermore,an As/Se co-exposure hydroponic experiment demonstrated that As uptake and accumulation in plants was reduced by increasing Se(IV)concentrations.The 50% growth inhibition concentration(IC50)values for As in plants were increased about one-fold and two-fold under co-exposure with 5 and 10μmol/L Se(IV),respectively.In conclusion,strain T3F4 improves Se uptake but decreases As uptake by plants via oxidation of As and Se,resulting in decrease of soil As bioavailability and As/Se competitive absorption by plants.This provides a potential bioremediation strategy for Se biofortification and As immobilization in As-polluted soil.

Molecular mechanism of flowering time regulation in Brassica rapa:similarities and differences with Arabidopsis

Properly regulated flowering time is pivotal for successful plant reproduction.The floral transition from vegetative growth to reproductive growth is regulated by a complex gene regulatory network that integrates environmental signals and internal conditions to ensure that flowering takes place under favorable conditions.Brassica rapa is a diploid Cruciferae species that includes several varieties that are cultivated as vegetable or oil crops.Flowering time is one of the most important agricultural traits of B.rapa crops because of its influence on yield and quality.The transition to flowering in B.rapa is regulated by several environmental and developmental cues,which are perceived by several signaling pathways,including the vernalization pathway,the autonomous pathway,the circadian clock,the thermosensory pathway,and gibberellin(GA)signaling.These signals are integrated to control the expression of floral integrators BrFTs and BrSOC1s to regulate flowering.In this review,we summarized current research advances on the molecular mechanisms that govern flowering time regulation in B.rapa and compare this to what is known in Arabidopsis.

Editing of eIF(iso)4E.c confers resistance against Turnip mosaic virus in Brassica rapa

Turnip mosaic virus(TuMV)constitutes one of the primary diseases affecting Brassica rapa,severely impacting its production and resulting in crop failures in various regions worldwide.Recent research has demonstrated the significance of plant translation initiation factors,specifically the eIF4E and eIF4G family genes,as essential recessive disease resistance genes.In our study,we conducted evolutionary and gene expression studies,leading us to identify e IF(iso)4E.c as a potential TuMV-resistant gene.Leveraging CRISPR/Cas9 technology,we obtained mutant B.rapa plants with edited eIF(iso)4E.c gene.We confirmed eIF(iso)4E.c confers resistance against TuMV through phenotypic observations and virus content evaluations.Furthermore,we employed ribosome profiling assays on eif(iso)4e.c mutant seedlings to unravel the translation landscape in response to TuMV.Interestingly,we observed a moderate correlation between the fold changes in gene expression at the transcriptional and translational levels(R^(2)=0.729).Comparative analysis of ribosome profiling and RNA-seq data revealed that plant-pathogen interaction,and MAPK signaling pathway-plant pathways were involved in eIF(iso)4E.c-mediated TuMV resistance.Further analysis revealed that sequence features,coding sequence length,and normalized minimal free energy,influenced the translation efficiency of genes.Our study highlights that the loss of e IF(iso)4E.c can result in a highly intricate translation mechanism,acting synergistically with transcription to confer resistance against TuMV.

The influence of Lactobacillus plantarum fermentation in selenium-enriched Brassica napus L.:changes in the nutritional constituents,bioactivities and bioaccessibility

Selenium(Se)-enriched Brassica napus L.is a valuable organic Se supplement.In this study,the fermentation broth enriched with organic Se(FFS)was prepared using Lactobacillus plantarum to ferment the substrate of Se-enriched Brassica napus L.Significant increases were observed after fermentation in total sugars,reducing sugars,soluble proteins,total phenolic content(TPC),and total flavonoid content(TFC).The organic Se was retained at a concentration of 54.75 mg/g in the freeze-dried sample.Principal component analysis and cluster analysis showed good separation between the FFS and unfermented(FS)groups.Fragrant 2-ethyloxetane had the highest content among all volatiles,while sinapine had the highest content among all phenolic compounds.The fermentation process showed remarkable improvement in the abundance and concentration of volatile compounds and phenolic contents,making FFS exhibit strong antioxidant activity and inhibitory capacity againstα-glucosidase activity.The bioaccessibility of phenolic compounds was significantly greater in FFS compared to FS.ADMET analysis revealed that the majority of phenolic compounds contained in FFS did not exhibit mutagenicity toxicity,hepatotoxicity,skin sensitization,or blood-brain barrier penetration,indicating a favorable level of biosafety.Overall,our study provides a new insight into the further utilization of Se-enriched Brassica napus L.in foods.

Anti-fatigue activity of Brassica rapa L.extract and correlation among biochemical changes in forced swimming mice

Brassica rapa L.is an edible and medical plant in China used for treating various diseases,especially in the Tibet region.In this study,the chemical constituents of Brassica rapa L.extract(BE)was clarified by UHPLC-MS and anti-fatigue ability of BE was assessed through the behavior test and weight-loaded forced swimming test in mice.Then we determined several biochemical parameters related to fatigue to explore possible reasons.Results indicate that BE could significantly enhance exercise performance in mice,and there was a significant improvement in both grip-strength and the time on rota-rods.Meanwhile,BE showed significant anti-fatigue effects by decreasing the blood lactic acid(BLA),blood urea nitrogen(BUN),and creatine kinase(CK)levels and increasing the lactate dehydrogenase(LDH)and malondialdehyde(MDA)levels.Increases in superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)were observed and reactive oxygen species(ROS)levels was regulated.Liver and muscle glycogen levels and adenosine triphosphate(ATP)levels were also significantly increased.Pearson correlation analysis indicates that fatigue-related indexes including metabolites and energy-related indexes were significantly correlated with antioxidant levels.In conclusion,BE possesses remarkable anti-fatigue activity,thereby shows great potential for improving exercise performance and alleviating physical fatigue and can be considered as a functional food supplement for further development.

甘蓝型黄籽油菜粒色基因候选区间的QTL-Seq定位及连锁标记开发

甘蓝型油菜黄籽性状遗传来源较为复杂且易受环境条件影响,基因定位和分子标记开发难度大.相比于传统QTL定位,结合二代深度测序等生信方法直接对甘蓝型油菜黄籽基因进行染色体定位、基因挖掘和标记开发,将有助于黄籽遗传机理的研究.利用甘蓝型油菜黄籽临保系63-2和黑籽67-1配制杂交组合,构建F 2粒色分离群体.遗传分析表明:该群体中黄籽性状受1对隐性主效基因控制;以法国甘蓝型油菜Darmor-bzh基因组为参考,利用集团分离分析法和全基因组重测序将黄籽性状基因定位于C03染色体6.1~9.0 Mb置信区间内,同时基于基因组变异和聚丙烯酰胺凝胶电泳验证获得与粒色基因紧密连锁的SSR标记4个和InDel标记5个.

Dissecting the genetic architecture of glucosinolate compounds for quality improvement in flowering stalk tissues of Brassica napus

Glucosinolates(GSLs) and their hydrolytic products contribute to the quality traits of rapeseed flowering stalk tissues, such as taste, flavor and anticarcinogenic properties(Glucoraphanin). However, little is known about the genetic mechanisms of GSL accumulation in rapeseed flowering stalks. In this study, the variation and genetic architecture of GSL metabolites in flowering stalk tissues were investigated for the first time among a panel of 107 accessions. All GSL compounds exhibited continuous and wide variations in the present population. Progoitrin,glucobrassicanapin and gluconapin were the most abundant GSL compounds. Five quantitative trait loci(QTL) significantly associated with three GSL compounds were identified by genome-wide association study. GRA_C04 was under selected during modern breeding, in which the ratio of lower GSL haplotype(HAP2) in the accessions bred before 1990(52.56%) was significantly lower than that after 1990(78.95%). Four candidate genes, BnaA01. SOT16, BnaA06. SOT17, Bna A06. MYB51a, and Bna A06. MYB51b, were identified in the GTL_A01 and 4OH_A06 regions.These findings provide new insights into GSL biosynthesis in flowering stalk tissues and facilitate quality improvement in rapeseed flowering stalks.

A Genetic Linkage Map of Brassica campestris L.ssp. pekinensis (syn. B. rapa L. ssp. pekinensis)

A molecular genetic map of Chinese cabbage was constructed with a 102 recombinant inbred (RI) population from a cross of two cultivated Chinese cabbage lines 177 and 276, using AFLP and RAPD markers. 352 markers including 265 AFLP markers and 87 RAPD markers were integrated into 17 linkage groups. It covered a total of 2 665. 7 cM with an average interval of 7. 6 cM. AFLP marker is efficient for map construction while it easily forms clusters to cause big gaps in map. A total of 13.92 % abnormal segregation markers distributed in the map. The molecular genetic map is fundamental for gene localization, comparative genomics, and QTL mapping of important agronomic traits.

Cloning and Expressional Studies of the Voltage-dependent Anion Channel Gene from Brassica rapa L.

The voltage-dependent anion channel （VDAC） plays an essential role in the permeability of mltochondrial membrane. In the present study, we isolated a novel VDAC gene （brvdac） based on the assembly of expressed sequence tag sequences from Brassica rapa L. and explored its differential expression patterns In growth, tissues, abiotlc stress, and stress recovery. Results of a tissue-specific expression study in young seedlings Indicated that, of all tissues tested, brvdac expression was the highest in the leaves. Under cold, drought, and salt stresses, brvdac expression showed a transient Increase, and then returned to normal levels when the stress was removed. When plants were exposed to heat shock, there was no Increase in brvdac expression, whereas during recovery a quick and considerable increase in expression was observed. These observations indicate that dissimilar modulations of brvdactranscription may occur when plant cells encounter heat shock and the other three types of stress. In addition, phylogenetic analysis Implied that an earlier duplication of vdac probably occurred before the divergence between monocotyledons and dicotyledons.

Molecular cloning and expression analysis of turnip (Brassica rapa var. rapa) sucrose transporter gene family

In higher plants, sugars(mainly sucrose) are produced by photosynthetically assimilated carbon in mesophyll cells of leaves and translocated to heterotrophic organs to ensure plant growth and development. Sucrose transporters, or sucrose carriers(SUCs), play an important role in the long-distance transportation of sucrose from source organs to sink organs, thereby affecting crop yield and quality.The identification, characterization, and molecular function analysis of sucrose transporter genes have been reported for monocot and dicot plants. However, no relevant study has been reported on sucrose transporter genes in Brassica rapa var. rapa, a cruciferous root crop used mainly as vegetables and fodder.We identified and cloned 12 sucrose transporter genes from turnips, named BrrSUC1.1 to BrrSUC6.2according to the SUC gene sequences of B. rapa pekinensis. We constructed a phylogenetic tree and analyzed conserved motifs for all 12 sucrose transporter genes identified. Real-time quantitative polymerase chain reaction was conducted to understand the expression levels of SUC genes in different tissues and developmental phases of the turnip. These findings add to our understanding of the genetics and physiology of sugar transport during taproot formation in turnips.

基于QTL和转录组测序鉴定甘蓝型油菜耐旱候选基因

干旱胁迫严重限制了甘蓝型油菜种植面积的扩大和产量的提升。耐旱性是由多基因控制的复杂数量性状,将QTL定位与转录组测序相结合,是鉴定甘蓝型油菜耐旱候选基因的有效手段。本研究对甘蓝型油菜干旱敏感品系三六矮和耐旱品系科里纳-2构建的F2:6和F2:8重组自交系群体幼苗进行正常灌溉和干旱胁迫处理,测定地上部鲜重、地上部干重、叶片相对含水量、丙二醛和可溶性糖含量,利用SSR和SNP多态性分子标记构建遗传连锁图谱,鉴定耐旱相关QTL和候选区间,结合耐旱材料No11和干旱敏感材料No28的转录组测序,筛选耐旱相关候选基因。研究结果表明:干旱胁迫使甘蓝型油菜幼苗地上部鲜重、地上部干重和叶片相对含水量下降,使叶片丙二醛和可溶性糖含量上升;耐旱相关QTL和候选区间分布于A01、A02、A06、A08、A09、A10、C02、C03、C04、C06和C09染色体;对耐旱材料和干旱敏感材料正常灌溉、干旱24 h、36 h和48 h进行转录组分析,主要差异表达基因显著富集到光合作用、脂肪酸代谢、氨基酸代谢、植物激素信号转导、核糖体、昼夜节律及角质、木栓素和蜡质的生物合成等相关途径;将QTL与转录组测序相结合,鉴定到28个耐旱相关候选基因,主要编码FLC、bHLH105、TGA4、TEM1、ERF003、ACO3、CHLI1、LHCB6和PORC等,具有转录因子活性、乙烯产生和信号传导、叶绿素生物合成与结合、叶绿素氧化还原酶以及编码核糖体相关蛋白等功能。这些结果可为揭示甘蓝型油菜耐旱机理及分子标记辅助选育耐旱新品种奠定基础。

Development and Characterization of Microsatellite Markers in Brassica rapa ssp.chinensis and Transferability Among Related Species

Simple sequence repeat （SSR） or microsatellite marker is a valuable tool for several purposes, such as mapping, fingerprinting, and breeding. In the present study, an intersimple sequence repeat （ISSR）-PCR technique was applied for developing SSR markers in non-heading Chinese cabbage （Brassica rapa）. A total of 190 SSRs were obtained. Among these, AG or CT （54.7%） was the most frequent repeat, followed by AC or GT （31.6%） of the microsatellites. The average number of the SSRs length array was 16 and 10 times, respectively. Based on the determined SSR sequences, 143 SSR primer pairs were designed to evaluate their transferabilities among the related species of Brassica. The number of alleles produced per marker averaged 2.91, and the polymorphism information content （PIC） value ranged from 0 to 0.863 with an average of 0.540. Monomorphism was observed in 16 primer pairs. The transferability percentage in CC genome was higher than in BB genome. More loci occurred in the BBCC genome. This result supported the hypothesis that BB genome was divergent from A and C genomes, and AA and CC genomes were relatively close. The polymorphic primers can be exploited for further evolution, fingerprinting, and variety identification.

Genome-wide identification and characterization of the lateral organ boundaries domain gene family in Brassica rapa var.rapa

The Lateral Organ Boundaries Domain(LBD)genes encode highly conserved plant-specific LOB domain proteins which regulate growth and development in various species.However,members of the LBD gene family have yet to be identified in Brassica rapa var.rapa.In the present study,fifty-nine LBD genes were identified and distributed on 10 chromosomes.The BrrLBD proteins are predicted to encode hydrophobic polypeptides between 118 and 394 amino acids in length and with molecular weights ranging from 13.31 to 44.24 kDa;the theoretical pi for these proteins varies from 4.83 to 9.68.There were 17 paralogous gene pairs in the BrrLBD family,suggesting that the amplification of the BrrLBD gene family involved largescale gene duplication events.Members of the BrrLBD family were divided into 7 subclades(class I a to e,class II a and b).Analysis of gene structure and conserved domains revealed that most BrrLBD genes of the same subclade had similar gene structures and protein motifs.The expression profiles of 59 BrrLBD genes were determined through Quantitative Real-time fluorescent PCR(qRT-PCR).Most BrrLBD genes in the same subclade had similar gene expression profiles.However,the expression patterns of 7 genes differed from their duplicates,indicating that although the gene function of most BrrLBD genes has been conserved,some BrrLBD genes may have undergone evolutionary change.

大白菜BrMLP328的克隆、表达及功能验证

【目的】克隆大白菜BrMLP328基因,对其表达模式进行分析,并验证对花期调控的功能,为进一步探究该基因在大白菜成花调控过程的作用机理奠定基础。【方法】运用RT-PCR克隆BrMLP328,并进行生物信息学分析;利用RT-qPCR测定该基因的相对表达量;构建过表达载体并通过蘸花法转化野生型拟南芥,比较T_(2)代植株与野生型的开花时间差异。【结果】BrMLP328的CDS全长为456 bp,编码151个氨基酸,蛋白相对分子质量为17493.82 Da,定位于细胞核。BrMLP328在大白菜茎中的表达量最高,根中次之,花蕾中最低;茎尖生长点中的表达量表现为春化后升高,之后在花芽分化阶段迅速下降,并维持在很低的水平。过表达BrMLP328的拟南芥开花时间比野生型延迟了1.46-3.09 d。【结论】从大白菜中克隆得到BrMLP328基因,其表达量在不同组织及不同成花阶段有所不同,该基因能够延迟开花。

Development of InDel Markers for Brassica rapa Based on a High-resolution Melting Curve

Brassica rapa is one of the most important leafy vegetable crops with large cultivated area in China.To increase the availability of DNA markers in B.rapa,we developed insertion-deletion(InDel)markers utilizing high-resolution melting(HRM)curve analysis.We designed primers for 252 InDels(≥3 bp)evenly distributed in the genome and tested gene polymorphisms with eight accessions.In total,208 markers were specifically amplified,and 148 InDels with polymorphism were genotyped successfully using HRM.We further analyzed the correlation with InDel size,GC number,and predicted the difference in Tm values(Tm)using 208 markers with specific amplification.We found that the success rate of InDel markers was correlated with the GC number of InDel and the predicted-Tm,but not clearly correlated with the length of InDel.When the GC number within InDel was≥8,the successful rate exceeded 90.0%.When the predicted-Tm reached 0.5°C,the success rate was greater than 90.0%,and when it was≥0.6°C,the rate climbed to 100.0%,indicating their role as the optimal parameter for successful development of an applicable InDel marker.The polymorphic InDel markers can be easily genotyped using HRM.They are of great value in genetic analysis,construction of linkage map,and molecular marker-assisted selection in B.rapa.

Genetic Diversity of European and Chinese Oilseed Brassica rapa Cultivars from Different Breeding Periods

The Brassica oilseed crops went through two major breeding bottlenecks during the introgression of genes for zero erucic acid and low glucosinolate content, respectively, which may lead to reduced genetic biodiversity of the crop. This study investigates the impact of these bottlenecks on the genetic diversity within and across European and Chinese winter B. rapa cultivars. We compared eight cultivars from Europe and China, representing three different seed qualities from three different breeding periods： （1） high erucic acid, high glucosinolates （＋＋）; （2） zero erucic acid, high glucosinolates（0＋）; （3） zero erucic acid, low glucosonolates （00, canola quality）. Diversity was estimated on 32 plants per cultivar, with 16 simple sequence repeat （SSR） markers covering each of the B. rapa linkage groups. The analysis of molecular variance （AMOVA） showed that genetic variations within cultivars, across cultivars and across regions （Europe and China） were significant, with about 60% of the total variation within cultivars. There was a slight, but non-significant loss in genetic diversity within cultivars when comparing the three breeding periods as indicated by effective number of alleles （2.39, 2.23, and 1.99 for breeding periods 1, 2, and 3, respectively）, Shannon information index （0.93, 0.90, 0.75）, and expected heterozygosity （0.51, 0.49, 0.42）. By cluster analysis （UPGMA dendrogram） and principal coordinate analysis, Chinese and European cultivars were clearly divided into two distinct groups. In conclusion, quality improvement did not significantly reduce the genetic diversity of European and Chinese B. rapa cultivars.