镉胁迫对小白菜(Brassica campestris L.)抗氧化机理的影响

采用水培的方法,研究了不同Cd2+水平(0、1、2.5、5、10、15mg·L-1)对小白菜(Brassica campestris L.)抗氧化酶(SOD、POD、CAT)活性、非酶物质(SH、GSH、PCs)含量以及生长的影响。结果表明,小白菜叶片和根系SOD活性随Cd处理质量浓度的增加呈降低的变化趋势,POD、CAT活性以及MDA含量随Cd处理质量浓度的增加而增加。小白菜的生物量、根长、株高、叶绿素质量分数随Cd处理质量浓度的增加显著降低(P<0.05),表明Cd抑制了小白菜的生长,破坏了叶绿素的合成。小白菜地上、地下部镉质量分数均随Cd处理质量浓度的增加而显著增加(P<0.05)。当Cd处理质量浓度为15mg·L-1,小白菜地上、地下部镉质量分数分别达到637.5、1663.0mg·kg-1,表明小白菜对Cd有良好的富集效果。小白菜根系与叶片中SH、GSH和PCs含量均随Cd处理质量浓度增加而增加的变化趋势,表明SH、GSH和PCs在解毒小白菜Cd毒害中起着重要作用。

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.

Effect of the Antisense BcMF12 Driven by the BcA9 Promoter on Gene Silencing in Brassica campestris L.ssp.chinensis

The study analyzed the silencing of BcMF12 gene regulated by BcA9 promoter in the transgenic pakchoi and confirmed the effect of antisense BcMF12 gene on the pollen development. A conserved BcMF12 gene fragment was amplified from the cDNA of flower buds in pakchoi （Brassica campestris L. ssp. chinensis, syn. B. rapa L. ssp. chinensis） and was fused to the anther specific BcA9 promoter. The plant antisense expression vector was constructed and then introduced into pakchoi via Agrobacterium-mediated transformation. The transgenic plants were screened by antibiotics and molecular analysis. PCR and Southern blot revealed that the antisense BcMF12-GUS fusion gene regulated by BcA9 promoter was integrated into transgenic plants. Northern blot suggested that the expression of BcMF12 gene was down-regulated significantly. The pollen germination rate of transgenic plants with antisense BcMF12 gene decreased as compared with that of the control plants. The expression of the gene BcMF12 related to the pollen development was inhibited by the antisense BcMF12 driven by BcA9 promoter, which consequently affected the pollen development in pakchoi.

Effects of Different Cadmium Levels on Active Oxygen Metabolism and H_2O_2-Scavenging System in Brassica campestris L.ssp.chinensis

The effects of different Cd (Cadmium) levels on generation of active oxygen speceies(AOS) and H2O2-scavenging system in the leaves of Brassica campestris L. ssp. chinensiswere studied. The results showed that generation rate, and H2O2 content were enhancedand malondialdehyde (MDA) content increased with the increase of Cd concentrations inthe growth medium. The activities of ascorbate peroxidase (APX), dehydroascorbatereductase (DR) and glutathione reductase (GR) were promoted by the addition of Cd.Exposed to Cd also increased the contents of ascorbate (AsA) and glutathione (GSH) in theleaves.

Identifying Cytoplasmic Male Sterile Types of Chinese Cabbage(Brassica campestris L.)by Molecular Markers

Different sterile cytoplasm types of nine cabbage cytoplasmic male sterile materials were identified by molecular marker in the study, in order to better use molecular marker to conduct the assisted breeding in the future. Genomic DNA was isolated from Chinese cabbage by CTAB method. The design of two pairs of specific primers was performed on conserved flanking region of orf138 gene in the GenBank. PCR was performed with genomic DNA of the nine Chinese cabbage materials. The bands were sequenced. The homologous comparison was conducted in NCBI, and finally, the type of sterile cytoplasm was determined. The results showed that the bands were amplified only in four Chinese cabbage male sterile materials with two pairs of specific primers PUPIl and PIII/PIV, while the other five materials did not obtain the relative bands. The result was consistent with the field sterility identification. And then four molecular markers of Chinese cabbage Ogura cytoplasmic male sterility （CMS） were obtained. After conducting a homologous comparative analysis with BLAST in GenBank, it was found that the homologous degree was 100% in specific segments of tbe tbree sterility materials （L1-CI, L3-CI and L3- F1 ） and Ogu orf138 gene （GenBank accession No. ： HQ149728） of the reported broccoli Ogu CMS. The homologous degree of L1-F1 was 99% with a variation point. The type of cytoplasmic male sterility of the other five materials needed further research. Four materials of the nine were identified as the radish cytoplasmic male sterility materials and four molecular markers were obtained.

Genetic linkage map of Brassica campestris L.using AFLP and RAPD markers

A genetic linkage map comprised of 131 loci was constructed with an F2 population derived from an inter-subspecific cross between Brassica campestris L.ssp.chinensis cv.aijiaohang” and ssp.rapifera cv.,”'isihai”.The genetic map included 93 RAPD loci,36 AFLP loci and 2 morphological loci organized into 10 main linkage groups(LGs) and 2 small groups,covering 1810.9cM with average distance between adjacent markers being approximately 13.8cM.The map is suitable for identification of molecular markers linked to important agronomic traits.QTL analysis,and even for marker-assisted selection in breeding programs of Chinese cabbage and turnip.

Genetic Variation and Correlation Analysis on Seed Oil Content and Protein Content of Brassica campestris L.Germplasm Resources

The content of oil and protein in 84 germplasm materials of Brassica campestris L. from all over the country was tested. In Guiyang environment,the oil content and protein content of these materials showed abundant variation,and were divided into three groups. Correlation analysis showed that there was a significant negative correlation between oil content and protein content of B. campestris L. seeds,and the application and formation mechanism of the negative correlation were also discussed.

国五国六柴油车尾气颗粒物对小白菜(Brassica campestris L.)的生态毒性

为研究柴油车尾气颗粒物对植物的毒性效应,本研究以执行国五、国六两种排放标准的柴油车为研究对象,测定其尾气颗粒物中重金属含量,并以小白菜(Brassica campestris L.)为受试植物,分析了两种颗粒物对小白菜的毒性效应.结果表明:(1)国五、国六柴油车尾气颗粒物中13种重金属总含量分别为1.04 g·kg^(-1)和0.47 g·kg^(-1),国五柴油车尾气颗粒物重金属含量高于国六柴油车;(2)在两种颗粒物的高浓度胁迫下,小白菜体内叶绿素以及蛋白质的含量均出现显著降低趋势;(3)随着两种颗粒物浓度的升高,植物体内部分氧化应激的酶指标超氧化物歧化酶(SOD)、过氧化氢酶(CAT)呈先上升后下降的趋势,而过氧化物酶(POD)以及丙二醛(MDA)、谷胱甘肽(GSH)呈上升趋势,颗粒物的污染能对小白菜产生较为显著的氧化胁迫效应.(4)21 d的毒性实验后,国五、国六柴油车尾气颗粒物对小白菜鲜重的半数有效浓度(EC50)值分别为76.27 mg·L^(-1)和104.48 mg·L^(-1).综合来看,国六标准的实施有效控制了颗粒物中重金属的含量,并一定程度地降低了其对小白菜的毒性.

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.

Role of nitrification inhibitor DMPP(3,4-dimethylpyrazole phosphate) in NO^-_3-N accumulation in greengrocery( Brassica campestris L. ssp. chinensis ) and vegetable soil

The influence of nitrification inhibitor(NI) 3,4 dimethylpyrazole phosphate(DMPP) on nitrate accumulation in greengrocery( Brassica campestris L. ssp. chinensis ) and vegetable soil at surface layer were investigated in field experiments in 2002 and 2003 Results showed that NI DMPP took no significant effect on yields of edible parts of greengrocery, but it could significantly decrease NO - 3 N concentration in greengrocery and in vegetable soil at surface layer. In addition, NI DMPP could reduce the NO - 3 N concentration during the prophase stage of storage.

Effect of Nitrogen and Sulfur Supply on Glucosinolates in Brassica campestris ssp.chinensis

Glucosinolates （GSs） are a group of plant secondary metabolites containing abundant nitrogen （N） and sulfur （S） mainly in Brassica and have the beneficial effects on human health including anti-carcinogenic, cholesterol-reducing and other pharmacological effects. The objective of this study was to investigate the effect of different concentrations of N （5, 10, and 20 mmol L-a, denoted by N5, N10 and N20） and S （0,5, 1, and 2 mmol L^-1, denoted by S0.5, S1 and S2） on the yield and GSs in pakchoi （Brassica campestris L. ssp. chinensis var. communis） in hydroponics. Results showed that N10 and N20 significantly enhanced the yield compared with N5, however, N20 had a negative effect relative to N10. Only with N10 and N20 low S supply （S0.5） reduced the yield. The concentrations of aliphatic GSs, aromatic GS and total GSs were enhanced by N5 and indolyl GSs were enhanced by N20. S2 enhanced the concentration of individual GS and total GSs. The concentrations of indolyl GSs were maximized in N20S2 treatment, whereas the highest concentrations of aliphatic GSs, aromatic GS and total GSs were found in N5S2 treatment. Effects of N and S on aliphatic GSs were higher than on indolyl GSs. The results suggest that the accumulation of aliphatic GSs and aromatic GS could be enhanced by low N and high S and restricted by high N while that of indolyl GSs could be enhanced by high N and high S.

Differential Expression Analysis of Genic Male Sterility A／B Lines in Chinese Cabbage—Pak—Choi（Brassica campestris ssp.chinensis Makino）

To determine differential expression of genie male sterility A/B lines in Chinese cabbage-pak-choi (Brassica campestris ssp. chinensis Makino var. communis Tsen et Lee), we used the RNA fingerprinting technique, cDNA-AFLP analysis, in different developmental stages and different tissues. While no obvious differential expressions were observed in rosette leaves, florescence leaves, and scapes, some differential expressions were found in alabstrums of A/B lines and among leaves, scapes and alabstrums. We analyzed the al-abstrums collected in different developmental stages with 10 primer combinations. We got a unique band between middle size alabstrums and large alabstrums in B line in one of the ten pair primers, and in another one pair, one band reflecting a higher gene-expression level in A line than that in B line was obtained. No unique bands were found with the other primer combinations. The bands reflecting different gene-expression level were confirmed by Northern hybridization. The results indicated that cDNA-AFLP was a suitable tool for studying differential expression of genie male sterility in plants. SDS-polyacrylamide gel electrophoresis patterns of soluble proteins further verified the difference in A/B lines.

Nitrogen Dioxide-Induced Responses in Brassica campestris Seedlings: The Role of Hydrogen Peroxide in the Modulation of Antioxidative Level and Induced Resistance

This article investigates the responses of Brassica campestris seedlings to an acute level of nitrogen dioxide （NO2） exposure in a plant growth chamber, and examines whether pretreating plants with hydrogen peroxide （H2O2） will alleviate NO2-caused injury. Twenty-eight-day-old B. campestris plants sprayed with 10 mmol L^-1 H2O2 aqueous solution （corresponding to approximate 1.0 mg H2O2 per single plant） were exposed to different concentrations of NO2 （0.25, 0.5, 1.0, and 2.0 μL L^-1, respectively） for 24 h under controlled environment. To measure the plant biomass, the plants were fumigated with the same NO2 concentrations as mentioned above for 7 h per day （8.00-15.00） for 7 days. As a control, charcoal filtered air alone was applied. Data were collected on plant biomass, total chlorophyll, photosynthetic rate, stomatal conductance, nitrate and nitrate reductase （NR）, antioxidative enzymes, ascorbate （ASA）, and malondialdehyde （MDA）, immediately after exposure. The results showed that exposure to a moderate dose of NO2 （e.g., 0.25 μL L^-1） had a favorable effect on plants, and the dry weight of the above-ground part increased, whereas the exposure to high NO2 concentrations （e.g., 0.5 μL L^-1 or higher） caused a reduction in the plant biomass and the total chlorophyll, when compared with the control. In addition, at 0.5 μL L^-1 or higher NO2 concentrations, prominent increases in the MDA level and superoxide dismutase （SOD） and NR activities were observed. Exposure to 1 μL L^-1 and higher NO2 resulted in necroses appearing on older leaves, and an increase in catalase （CAT） activity, decrease in ASA content, increased accumulation of NO3^-, and reduction in photosynthesis, when compared with the controls. No changes were detected in stomatal conductance under NO2 fumigation. The pretreatment with 10 mmol L^-1 H2O2 alleviated significantly NO2- caused biomass decrease and photosynthetic inhibition when compared with H2O2-untreated plants. Under NO2 fumigation, further induction in SOD and CAT activities occurred in H2O2 treated plants when compared with H2O2- untreated plants. The effect of NO2 on the ASA and MDA contents was also absent in H2O2-treated plants. However, the H2O2 treatment did not alter the nitrate content and NR activity in plants under NO2 fumigation. The H2O2 treatment caused a lower rate of stomatal conductance. Taken together, these data suggest that fumigation with an acute level of NO2 causes oxidative damage to B. campestris seedlings. The H2O2 pretreatment markedly protects plants against NO2 stress and this may be associated with inducible antioxidative level. NO2 fumigation contributes, at least in part, to the enhanced levels of nitrate in B. campestris leaves.

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.

Cloning and Characterization of the Microspore Development-Related Gene BcMF2 in Chinese Cabbage Pak-Choi （Brassica campestris L. ssp. chinensis Makino）

For the sake of providing some important information relevant to the study of the molecular mechanism of genic male sterility in plants, gene differential expression in flower buds at different developmental stages, as well as in rosette leaves, florescence leaves, and scapes was analyzed using cDNA amplified fragment length polymorphism (cDNA-AFLP) in the genic male sterile A and fertile B line of Chinese cabbage pak-choi. Following amplification of 125 pairs of primer combinations, 11 differential fragments were obtained, of which eight were from the B line and the other three were from the A line. Of 11 differential fragments, four were verified by Northern hybridization that were expressed preferentially in fertile flower buds. Results of GenBank BLAST showed that one fragment was with unknown function, whereas the other fragments have strong nucleotide sequence similarities with the polygalacturonase (PG) gene, the pectinesterase (PE) gene, and the polygalacturonase inhibitory protein (PGIP4) gene. Only full-length cDNA from the differential fragment BcMF-A18T16-1 was amplified by rapid amplification of cDNA ends (RACE) and Northern analysis showed that this fragment was expressed only in medium and large-sized flower buds of the B line. The full-length cDNA, designated as BcMF2 (Brassica campestris Male Fertile 2), was 1 485 bp long and was composed of a 1 263-bp open reading frame, which had 83% nucleotide similarity to a PG gene from Arabidopsis encoding polygalacturonase. Analysis of the basic structure of the protein revealed that it had one polygalacturonase active site (RVTCGPGHGLSVGS) at 256th site of amino acids and was classified as being a member of family 28 of the glycosyl hydrolases. The role of the BcMF2 gene on microspore development is discussed in the present paper.

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。

甘蓝型油菜RIL群体苗期根系耐铝性鉴定及评价方法研究

为减少铵肥的大量施用以及酸雨频降引发的耕地酸化,从而影响作物的生长,利用综合评价方法通过幼苗期根系表型筛选耐铝种质.以甘蓝型油菜重组自交系(RIL)亲本10D130和中双11为材料筛选苗期适宜的铝胁迫浓度,使用该浓度处理RIL内138个品种(系)幼苗,对其根长、根表面积、根平均直径、根体积、根交叉数、根尖数和根干质量7个根系指标的铝毒单项耐性系数进行变异系数分析、相关性分析、主成分分析、系统聚类分析和逐步回归分析,并采用隶属函数法综合评价不同油菜品种(系)根系的耐铝特性.结果表明:138份油菜品种(系)间各项根系指标差异有统计学意义(p<0.05);筛选出甘蓝型油菜幼苗期耐铝毒品种(系)27034,27036和27007等.根据灰色关联度及逐步回归分析结果,认为根据根长、根表面积、根体积、根交叉数等7个关键指标,可以初步判断甘蓝型油菜种质幼苗期的耐铝毒特性.通过这些方法综合评价油菜对铝的耐受性,可以避免单一指标的片面性和不稳定性,结果更为可靠.

Characterization of a novel gene, BcMF7,that is expressed preferentially in pollen of Brassica campestris L. ssp. chinensis Makino

Pollen formation is important for plant sexual reproduction. To identify the genes that are involved in pollen formation, we performed the genome-wide transcriptional profiling in the flower buds of both male meiotic cytokinesis (mmc) mutant and its wild-type plants of Brassica campestris L. ssp. chinen-sis, syn. B. rapa L. ssp. chinensis. cDNA-amplified fragment length polymorphism (cDNA-AFLP) analy-sis showed that the mmc mutation resulted in changes in expression of a variety of genes. BcMF7, a transcript-derived fragment (TDF) accumulated in the wild-type flower buds was further characterized. The BcMF7 gene has 1161 bp in length with two introns. The full-length BcMF7 cDNA has 609 bp in length and encodes a protein of 129 amino acids. The deduced amino acid sequence of BcMF7 protein shares no similarity to any function-known protein in Swiss-Prot database, but has 8 protein kinase C phosphorylation sites, 2 casein kinase II phosphorylation sites, 2 tyrosine kinase phosphorylation sites, 2 N-glycosylation sites and 2 N-myristoylation sites. Spatial and temporal expression patterns analysis showed that BcMF7 was expressed exclusively in pollen. The expression signal of BcMF7 was first detected at the tetrad stage of microspore development, reached a peak level at the uninucleate stage, and decreased to a slightly low level at the mature pollen stage. All these results show that BcMF7 may play a certain role in the signal transduction during pollen development.

BnbHLH92a negatively regulates anthocyanin and proanthocyanidin biosynthesis in Brassica napus

Yellow seed trait is a desirable characteristic with potential for increasing seed quality and commercial value in rapeseed,and anthocyanin and proanthocyanidins(PAs)are major seed-coat pigments.Few transcription factors involved in the regulation of anthocyanin and PAs biosynthesis have been characterized in rapeseed.In this study,we identified a transcription factor gene BnbHLH92a(BnaA06T0441000ZS)in rapeseed.Overexpressing BnbHLH92a both in Arabidopsis and in rapeseed reduced levels of anthocyanin and PAs.Correspondingly,the expression profiles of anthocyanin and PA biosynthesis genes(TT3,BAN,TT8,TT18,and TTG1)were shown by quantitative real-time PCR to be inhibited in BnbHLH92a-overexpressing Arabidopsis seeds,indicating that BnbHLH92a represses the anthocyanin and PA biosynthesis pathway in Arabidopsis.BnbHLH92a physically interacts with the BnTTG1 protein and represses the biosynthesis of anthocyanins and PAs in rapeseed.BnbHLH92a also binds directly to the BnTT18 promoter and represses its expression.These results suggest that BnbHLH92a is a novel upstream regulator of flavonoid biosynthesis in B.napus.