BnGLO4 gene cloning and bioinformatics analysis in Brassica napus L

High oleic acid rapeseed oil offers superior nutritional and health benefits,but its mass production is limited due to poor resistance and slightly lower yield.Photosynthesis serves as the foundation of biological survival and closely correlates with crop resistance to stresses,yield,and quality.To identify photosynthesis-related genes,transcriptome sequencing was conducted on high oleic acid rapeseed Gaoyousuan No.1 and low oleic acid rapeseed Xiangyou 15 resulting in the identification of a total of 9396 differentially expressed genes(4669 upregulated and 4727 down-regulated).From these genes nine candidate genes were screened using GO and KEGG analysis with BnGLO4 being selected for cloning purposes.The BnGLO4 gene fragment has a length of 1161 bp with an ORF sequence of 1092 bp encoding a theoretical isoelectric point of pI 7.60;it encodes an unstable lipid-soluble protein localized in peroxisomes without transmembrane structural domains or signal peptides.Its amino acid sequence homology was highest with that of BnaA01G0355200ZS,BnaA01G0355600ZS,BnaA05G0410400ZS,BnaC01G0441800ZS,and Brassica rapa(XP_009117145.1),Brassica napus(CDY39100.1),Brassica cretica(KAF3533604.1)and Brassica oleracea var.oleracea(XP_013610644.1)belonging to the same cruciferous family.The BnGLO4 gene may be associated with responses to abiotic stresses such as salt,drought,and temperature extremes along with photosynthesis and growth in rapeseed plants.The expression levels of the GLO4 gene(BnaA01G0355200 ZS)were highest in filaments while being higher at each stage in seeds and siliques with the highest expression level at day 14 in seeds.Expression was significantly upregulated after 3 h of salt stress treatment,reaching a maximum at 12 h before slightly decreasing at 24 h.The findings of this study lay a foundation for further investigation on photosynthesis and stress response in high oleic rapeseed.

Responses of Seed Yield and Economic Benefit of Winter Oilseed Rape(Brassica napus L.) to Different NPK Ratio and Dose

Field experiments were conducted during 2008-2010 to investigate the ef- fects of NPK fertilization on seed yield and economic benefit of a new hybrid cultivar of winter oilseed rape （Brassica napus L.） - Xiangzayou763, and to determine the optimum NPK ratio and dose in Hunan, China. The results showed that NPK ratio （1：0.50：0.50） with 180 kg/hm2 N, 90 kg/hm2 P2O5 and 90 kg/hm2 K20 was the optimum combination for the highest seed yield （2 231.13 kg/hm2） and economic benefit （9 816.97 Yuan/hm2）, of which 1 641.23 Yuan/hm2 being set for fertilizer in- vestment （VCR=4.11）. Besides, the effects of N, P and K fertilizers on seed yield and oil production of winter oilseed rape were not identical. N had the greatest ef- fect on plant growth of winter oilseed rape, followed by P and K. Total leaf number, green leaf number, leaf length and width, rhizome diameter, branch number, dry weight per plant and other agronomic characters in high N treatments were higher than those in low N treatments. By correlation and path analysis of yield components, the contribution rate to seed yield was found： effective silique number per plant〉seed number per silique〉l 000-seed weight.

A Study on Triacylglycerol Composition and the Structure of High-Oleic Rapeseed Oil

The composition of fatty acids in triacylglycerides （TAGs） and their position on the glycerol backbone de- termine the nutritional value of vegetable oil. In this study, gas chromatography and high-performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS） were used to analyze the compo- sition and distribution of fatty acids in TAGs of different rapeseed oils. Our results show the content of oleic acid in higb-oleic-acid rapeseed oil to be about 80%. In terms of the number of acyl carbon atoms （CN）, TAGs with CN52-54 were most abundant, with a maximum concentration at CN54 （80%）. The main type of TAG was oleic-oleic-oleic （OOO）, accounting for 71.75%, while oleic-oleic-linoleic （OOL） accounted for ？.56%, oleic-oleic-linolenic （OOLn） accounted for 4.81%, and stearic-oleic-oleic （SO0） accounted for 4.74%. Oleic acid in high-oleic-acid rapeseed oil was distributed in the following order of preference： sn-2 〉 sn-1/3. In high-erucic-acid rapeseed oil, however, oleic acid was enriched at the sn-1/3. These data show that the content of oleic acid can be as high as about 80% in high-oleic-acid material. This finding suggests that high-oleic-acid rapeseed oil has high nutritional value.

Identification and evaluation of high nitrogen nutrition efficiency in rapeseed(Brassica napus L.)germplasm

To establish identification and evaluation methods of N(nitrogen)absorption and utilization of rapeseed(Brassica napus L.),difference of N nutrition efficiency(NNE)among rapeseed germplasms and relationship between NNE and plant traits under various N application rates were analyzed in this research.Pot cultivating experiments were conducted to investigate NNE with 3 N application rates in soil(0.05,0.2 and 0.3 g/kg).A total of 12 rapeseed germplasms were planted,nitrogen absorption efficiency(NAE)and nitrogen utilization efficiency(NUE)in seedling stage,bolting stage,initial flowering stage,final flowering stage,and maturity stage were obtained.Results showed that bolting stage was the best period for NAE identification and evaluation.Low N application rate in soil(0.05 g/kg)was the best for NAE,and the indirect indexes were basal stem diameter,plant root dry weight and above ground plant dry weight.Maturity stage was the best period for NUE identification and evaluation.High N application rate in soil(0.3 g/kg)was the best for NUE,and indirect indexes were above ground plant dry weight and basal stem diameter.N application rates of 0.05 g/kg in soil was the best for nitrogen harvest index at maturity stage,and indirect indexes was number of pods per plant.Plant traits of rapeseed germplasms affected NNE.Higher basal stem diameter,plant root dry weight and above ground plant dry weight at bolting stage under low N application rate were important characteristics of N absorption in rapeseed.Higher above ground plant dry weight and basal stem diameter at maturity stage under high N application rate were important characteristics of N utilization.Higher number of pods per plant at maturity stage under lowe N application rate was an important characteristic of N harvest index.These results provided a reliable index for N management and provided theoretical basis for guiding rapeseed breeding.

Regulatory mechanisms of rapeseed petal color formation:Current research status and future perspectives

Flower color,an important rapeseed character,has great practical value and research significance.It has become an area of intensive research in recent years.This paper summarizes the latest research progress on rape flower color in terms of variety,source,pigment composition,formation mechanism,and omics.Moreover,it provides an overview of rape flower color breeding and omics.

Origin and evolution of fatty acid desaturase genes in oil crop Brassica napus

Fatty acid(FA)desaturases,as the key enzymes in lipid metabolism,are responsible for biosynthesis of the unsaturated fatty FAs,which play important roles in maintaining cell membrane integrity and multiple stress responses.Although attention has been drawn to some plant FA desaturase genes,their global landscape in oil crops is still lacking.Here,we performed systematic characterization and phylogenomic synteny network analyses of the FA desaturase gene family in polyploid oil crop B.napus and other 54 species covering major streptophyte lineages.A total of 1653 FA desaturase genes were identified from these plant genomes.Based on the broad-scale family phylogeny and functional domains,we proposed a unified eight-group classification system for angiosperm FA desaturases,and found that the origin of genes responsible for FA desaturation evolved early and some genes were absent in different species.Phylogenomic analyses revealed deeply conserved syntenic relationships within each of the eight FA desaturase groups.B.napus contains up to 93 FA desaturase genes from the eight groups.Recurrent duplication events in Brassicaceae contributed to the expansion of FA desaturase genes in B.napus,leading to further functional diversification.These FA desaturase genes exhibited spatio-temporal specific expression patterns in different tissues of B.napus,and a set of FA desaturase genes seem to be orchestrated by key transcriptional factors during seed development,such as zf-HD,B3,GATA3,PEI1,NFYA7,YAB1 and YAB2.Altogether,our data have inferred the evolutionary trajectory of this important gene family across distinct plant lineages,providing theoretical basis for future manipulation of FA desaturase genes to improve the seed oil quality of B.napus.

Progress of CRISPR/Cas9 technology in breeding of Brassica napus

Gene editing technology provides important technical basics for the research in plant functional genes and crop genetic improvement.CRISPR/Cas9-mediated gene editing is an effective experimental tool for crop genome directed editing in recent years,which has been widely used in many crops as rice,wheat and other crops.CRISPR/Cas9 system was expected to be a powerful experimental tool in genetic improvement and molecular design breeding of rapeseed.This paper,which based on the development history and the latest research of CRISPR/Cas9-mediated gene editing technology in rapeseed,summarized the progress of CRISPR/Cas9 including plant type improvement,yield traits,quality improvement,disease and stress resistance improvement,yellow seed creation and other utilizes at present.The application scope,development direction and target analysis method of this technology in rape were focused.The problems of CRISPR/cas9 system in rapeseed breeding were analyzed and the improvement strategies were discussed.Finally,views on direction of rapeseed breeding by gene editing were emphasized.

Identification of differentially expressed genes between Sclerotinia-resistant and its near-isogenic susceptible lines of Brassica napus infected with Sclerotinia sclerotiorum

The gene-expression profiles between the Sclerotinia-resistant and its nearisogenic susceptible rapeseed lines (Brassica napus) infected with Sclerotinia sclerotiorum were examined by microarray analysis. 102 differentially expressed genes (DEGs)were successfully identified, including genes highly related to pathogen resistance. Among these DEGs, 46 were up-regulated and 56 were down-regulated. To verify the reliability of microarray, 2 up-regulated genes (NM_130355 and NM_126666) and 1 down-regulated gene (NM_100191) were chosen and their expression level were detected by real-time fluorescence-based quantitative PCR analysis (RT-PCR). Subsequently, the 102 DEGs were GO (gene ontology) annotated, and to be classified into 22 categories, including enzymes,binding proteins, transcription factors, and proteins with unknown functions. Further subcellular localization prediction demonstrated that these DEGs might be located in/on intracellular region, cell wall, cell membrane, cytoplasm, nucleus, endoplasmic reticulum, chloroplasts and mitochondria. The analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways revealed that 10 DEGs were participated in several known biological pathways, including lysine biosynthesis, sulfur assimilation, cysteine metabolism, carotenoid biosynthesis, glyoxylic acid and oxalic acid metabolism etc. Taken together, the preliminary results would provide important information for exploring the molecular basis of Sclerotinia-resistance in Brassica napus.