Effects of Nitrogen Fertilizer Management on Biological Traits and Physiological Indexes at Seedling Stage and Yield of Directly-sown Rapeseed(Brassica napus L.)

Field experiments were carried out to study the effects of different nitroge- napplication rates and application times on biological traits and physiological indexes of directly-sown rapeseed （Brassica napus L.） at the seedling stage and investigate the relationship between these biological traits or physiological indexes at the seedling stage and yield, so as to provide scientific theoretical support for high yield and efficient fertilization management in production of winter rapeseed. Field trials were conducted in Chengdu plain of Sichuan Province under rice-rapeseed rotation system during the period of 2011-2012. The nitrogen application rate trial consisted of five nitrogen levels （0, 90, 180, 270 and 360 kg/hm2） and the nitrogen application time trial included NTl（single application as base fertilized）, NT2 （bottom application ＋one time of topdressing at seedling stage） and NT3 （bottom application＋two times of topdressing at seedling stage） under the same nitrogen rate （225 kg/hm2）. The results indicated that compared with no nitrogen application （NO） treatment, the in- crease of nitrogen fertilizer is beneficial to the increase of biological traits including plant height, green leaf number, leaf area index and dry weight of rapeseed at the seedling stage, the improvement of physiological indexes including total nitrogen content, chlorophyll content and soluble protein content of functional leaves, and the reduction of soluble sugar content. Nitrogen rate was linearly correlated with various biological traits at the seedling stage and physiological indexes including total nitro- gen content, chlorophyll content and soluble sugar content in functional leaves over- a/I, but in parabolic correlation with soluble protein content. Under the same nitrogen rate, NT2 treatment exhibited biological traits remarkably or significantly higher than NT1 treatment and NT3 treatment. The nitrogen application times were linearly cor- related with the physiological indexes of functional leaves at the seedling stage. The various biological traits and physiological index of functional leaves at the seedlings stage were in quadratic function parabolic correlation with seed yield, and the corre- lation was significant （P〈0.05）. Therefore, under the rice-rapeseed rotation system in Chengdu plain, the economic rational nitrogen rate is 180-225 kg/hm2, and the mode of bottom application ＋ one time of topdressing （NT2） is suitable.

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.

Comparions of Required Nitrogen Fertilizers by Hybrid Cultivar and Conventional Cultivar of Rapeseed(Brassica napus L.)

[Objective] The aim of this study was to understand the difference of N fertilizer requirement between hybrid rapeseed and conventional rapeseed. [Method] Two hybrid cultivars, ZY5628 and ZY7819, and the conventional cultivar ZS10, were compared through two field experiments. In Experiment 1, seed yield and optimum N application rate were assessed in the field with five N application treatments. In Expedment 2, N was applied uniformly at 180 kg/hm2, and plant biomass and N accumulation were measured at several developmental stages, while N use efficien- cy was calculated for rape at maturity. [Results] The experiment 1 results showed that seed yields of ZY5628 and ZY7819 were both significantly higher than that of ZS10, and compared to ZS10, optimum yield （plateau yield） was higher by 18.7% and 20.2%, while the recommended N application rate was lower by 9.5% and 9.6% for ZY5628 and ZY7819, respectively. The experiment 2 results showed that during vegetative development, all three cultivars exhibited similar accumulations of plant biomass and N, but through flowering and maturity ZY5628 and ZY7819 pro- duced more biomass, acquired more N, and utilized acquired N more efficiently to- wards seed production than ZS10. [Conclusion] With equivalent inputs, the hybrid rapeseed cultivars ZY5628 and ZY7819 tested herein yield more seed with higher N use efficiency than the conventional rapeseed ZS10. This information will be valu- able for growers seeking to improve efficiency while reducing costs of rape production in China.

Exogenous application of a low concentration of melatonin enhances salt tolerance in rapeseed(Brassica napus L.) seedlings

Melatonin is a naturally occurring compound in plants. Here, we tested the effect of exogenous melatonin on rapeseed（Brassica napus L.） grown under salt stress. Application of 30 μmol L^-1 melatonin alleviated salt-induced growth inhibition, and the shoot fresh weight, the shoot dry weight, the root fresh weight, and the root dry weight of seedlings treated with exogenous melatonin increased by 128.2, 142.9, 122.2, and 124.2%, respectively, compared to those under salt stress. In addition, several physiological parameters were evaluated. The activities of antioxidant enzymes including peroxidase（POD）, catalase（CAT） and ascorbate peroxidase（APX） were enhanced by 16.5, 19.3, and 14.2% compared to their activities in plants without exogenous melatonin application under salt stress, while the H2O2 content was decreased by 11.2% by exogenous melatonin. Furthermore, melatonin treatment promoted solute accumulation by increasing the contents of proline（26.8%）, soluble sugars（15.1%） and proteins（58.8%）. The results also suggested that higher concentrations（〉50 μmol L^-1） of melatonin could attenuate or even prevent the beneficial effects on seedling development. In conclusion, application of a low concentration of exogenous melatonin to rapeseed plants under salt stress can improve the H2O2-scavenging capacity by enhancing the activities of antioxidant enzymes such as POD, CAT and APX, and can also alleviate osmotic stress by promoting the accumulation of osmoregulatory substances such as soluble proteins, proline, and water soluble glucan. Ultimately, exogenous melatonin facilitates root development and improves the biomass of rapeseed seedlings grown under salt stress, thereby effectively alleviating the damage of salt stress in rapeseed seedlings.

Genetic Diversity of Testa Pigments and RAPD Marker of Yellow-Seeded Rapeseed (Brassica napus L.)

14 yellow-seeded rapeseed lines (Brassia napus L.) from different genetic sources were used to analyze diversity of testa pigments content, oil and protein content, and RAPD markers. The results showed that the anthocyanin and melanin were the most important pigments in testa and their content were responsible for the variation in seed color ranging from orange to black yellow, 14 yellow-seeded lines could be classified into 3 groups: high anthocyanin content group with anthocyanin content over 2. 54 mg g-1 DW, the seed color was light yellow or orange; low pigments content group with low content of anthocyanin and melanin, the testa was transparent and the seed color was light yellow, greenish yellow or twany; high melanin content group with melanin content over 178. 4U(A290nm) , the testa was black, the seed color was black yellow. Oil content changed from 36.2% to 45. 5%, protein content from 21.1% to 27.7% , and the correlation analysis revealed that the oil content is highly significantly negatively correlated with the protein content. The cluster analysis showed that the extensive genetic variation existed among 14 yellow-seeded lines by using unweighted paired group method with arithmetic average (UPGMA) based on RAPD markers which were amplified with decamer primers, the genetic similarity among them ranged from 0. 25 to 0.909, and 14 yellow-seeded lines could put into 2 clusters corresponding to genome difference.

Foliar K application delays leaf senescence of winter rapeseed(Brassica napus L.) under waterlogging

To better understand waterlogging effect on leaf senescence in winter rapseed (Brassica napus L.) during flowering stage, experiments were designed to explore foliar K application influences on adverse effects of waterlogging stress. Winter rapeseed was sprayed with K after waterlogging at initial flowering stage. Results indicated that waterlogging significantly decreased leaf net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr). It also declined maximum quantum yield of PS II (Fv/Fm), quantum yield of electron transport (ΦPS II) and photochemical quenching (qP), but increased leaf non-photochemical quenching (NPQ) and minimal fluorescence (Fo). Interestingly, exogenous application of K significantly alleviated waterlogging-induced photosynthesis inhibition. Foliar K application increased RuBisCO activation, chlorophyll and soluble protein contents, while significantly decreased MDA content under waterlogging stress. Moreover, K supplementation improved accumulation of K+, Ca2+, Mg2+, N, Zn2+, Mn2+, Fe2+ in leaves. In general, foliar K application is effective inalleviating deleterious effects of waterlogging stress and delays leaf senescence of winter rapeseed.

Identification of suitable reference genes in leaves and roots of rapeseed (Brassica napus L.) under different nutrient deficiencies

Nutrient deficiency stresses often occur simultaneously in soil. Thus, it＇s necessary to investigate the mechanisms underlying plant responses to multiple stresses through identification of some key stress-responsive genes. Quantitative real-time PCR （qRT-PCR） is essential for detecting the expression of the interested genes, of which the selection of suitable reference genes is a crucial step before qRT-PCR. To date, reliable reference genes to normalize qRT-PCR data under different nutrient deficiencies have not been reported in plants. In this study, expression of ten candidate reference genes was detected in leaves and roots of rapeseed （Brassica napus L.） after implementing different nutrient deficiencies for 14 days. These candidate genes, included two traditionally used reference genes and eight genes selected from an RNA- Seq dataset. Two software packages （GeNorm, NormFinder） were employed to evaluate candidate gene stability. Results showed that VHA-E1 was the highest-ranked gene in leaves of nutrient-deficient rapeseed, while VHA-G1 and UBC21 were most stable in nutrient-deficient roots. When rapeseed leaves and roots were combined, UBC21, HTB1, VHA-G1 and A CT7 were most stable among all samples. To evaluate the stabilities of the highest-ranked genes, the relative expression of two target genes, BnTrxl;1 and BnPhtl;3 Were further determined. The results showed that the relative expression of BnTrxl;1 depended on reference gene selection, suggesting that it＇s necessary to evaluate the stability of reference gene prior to qRT-PCR. This study provides suitable reference genes for gene expression analysis of rapeseed responses to different nutrient deficiencies, which is essential for elucidation of mechanisms underlying rapeseed responses to multiple nutrient deficiency stresses

Recent Advances,Problems and Outlooks in Rapeseed(Brassica napus L.)Breeding in China

As a big rapeseed （Brassica napus L.） producing and consuming country, China provides more and more rapeseea oil year by year. With the development of demand for rapeseed and import of edible oil, rapeseed breeding and production is fac- ing a great challenge. New situation has proposed higher requirements to yield, oil quality and safety, etc. In the review, some aspects about rapeseed breeding in China were reported, including breeding of high-oil content rapeseed, breeding of extremely early-maturing rapeseed, development of mechanization and development of chemical emasculation. Some prospects and expec- tations were also proposed.

Worldwide rapeseed (Brassica napus L.) research:A bibliometric analysis during 2011–2021

Rapeseed(Brassica napus L.) is the world?s second produced oilseed and accounts for nearly 12% of world major vegetable oil production.For the last 10 years,the production,planting area,and yield of rapeseed have been stable,with improvement of seed quality and especially seed oil content.This paper presented the worldwide rapeseed research by using the bibliometric analysis of papers published during the period 2011–2021.In total,7617 articles and reviews were included in this analysis.Our results showed that the global publication on rapeseed increased substantially in the past 11 years,and the number of publications of China grew significantly in particular.China was the largest contributor to rapeseed research with higher H-index value and number of citations compared to the other countries.China also had the largest number of leading universities and institutions,of which Huazhong Agricultural University was the most productive.The scientific mapping including co-authorship network of countries/regions and authors,and co-occurrence network of author keywords were analyzed using VOSviewer software.The most common rapeseed research topics included oil,rapeseed meal,yield,biodiesel,fatty acids,salt stress,and proteins,while the current research focused on topics such as:abiotic stress,evolution,expression analysis,phylogenetic analysis,heterosis,polyploidy,and transcriptomics.This paper depicts the knowledge structure of current global rapeseed research that may help direct the future studies for relevant researchers.

Comparison of transcriptomes undergoing waterlogging at the seedling stage between tolerant and sensitive varieties of Brassica napus L.

RNA sequencing of the sensitive GH01 variety of Brassica napus L. seedling roots under 12 h of waterlogging was compared with previously published data of the ZS9 tolerant variety to unravel genetic mechanisms of waterlogging tolerance beyond natural variation. A total of 2 977 genes with similar expression patterns and 17 genes with opposite expression patterns were identiifed in the transcription proifles of ZS9 and GH01. An additional 1 438 genes in ZS9 and 1 861 genes in GH01 showed strain speciifc regulation. Analysis of the overlapped genes between ZS9 and GH01 revealed that waterlogging tolerance is determined by ability to regulate genes with similar expression patterns. Moreover, differences in both gene expression proifles and abscisic acid (ABA) contents between the two varieties suggest that ABA may play some role in waterlogging tolerance. This study identiifes a subset of candidate genes for further functional analysis.

油菜(B.napus L.)硼素营养与结实性的研究

硼营养不足,油菜植株各器官含硼量均下降,下降幅度因器官而异,而以花器官下降幅度最大。缺硼时,花器发育异常,雄蕊在解剖生理上的异常现象尤为突出,严重时花粉败育,花蕾脱落,甚至出现颗粒无收的现象。花粉败育表现为花粉囊空瘪,核质解体,无孢原组织分化,绒毡层发育异常,小孢子原生质团溢出药壁外等现象。硼营养不足降低了花药中可溶性糖、淀粉、游离脯氨酸和可溶性蛋白质含量。同时花粉活力和呼吸强度也降低。研究还表明油菜品种对硼营养反应存在基因型差异。宁油8号比宁油7号对缺硼反应更为敏感。缺硼条件下,改善硼营养后,油菜各器官含硼量提高最多的是花器,并使有效分枝数、有效角果数和每角平均实粒数增加,从而提高油菜籽粒产量。

Exogenous strigolactones promote lateral root growth by reducing the endogenous auxin level in rapeseed

Strigolactones(SLs)are newly discovered plant hormones which regulate the normal development of different plant organs,especially root architecture.Lateral root formation of rapeseed seedlings before winter has great effects on the plant growth and seed yield.Here,we treated the seedlings of Zhongshuang 11(ZS11),an elite conventional rapeseed cultivar,with different concentrations of GR24(a synthetic analogue of strigolactones),and found that a low concentration(0.18μmol L–1)of GR24 could significantly increase the lateral root growth,shoot growth,and root/shoot ratio of seedlings.RNA-Seq analysis of lateral roots at 12 h,1 d,4 d,and 7 d after GR24 treatment showed that 2301,4626,1595,and 783 genes were significantly differentially expressed,respectively.Function enrichment analysis revealed that the plant hormone transduction pathway,tryptophan metabolism,and the phenylpropanoid biosynthesis pathway were over-represented.Moreover,transcription factors,including AP2/ERF,AUX/IAA,NAC,MYB,and WRKY,were up-regulated at 1 d after GR24 treatment.Metabolomics profiling further demonstrated that the amounts of various metabolites,such as indole-3-acetic acid(IAA)and cis-zeatin were drastically altered.In particular,the concentrations of endogenous IAA significantly decreased by 52.4 and 75.8%at 12 h and 1 d after GR24 treatment,respectively.Our study indicated that low concentrations of exogenous SLs could promote the lateral root growth of rapeseed through interaction with other phytohormones,which provides useful clues for the effects of SLs on root architecture and crop productivity.

Regional Evaluation of Winter Rapeseed Response to K Fertilization, K Use Efficiency, and Critical Level of Soil K in the Yangtze River Valley

The investigation was carried out to study the response of winter rapeseed to potassium （K） feritlization and the critical soil available K level for current winter rapeseed production in the Yangtze River Valley （YRV） of China. A total of 132 field experiments were conducted in fields of farmers in the major winter rapeseed growing areas in YRV in 2000/2001 and 2004/2005 to 2006/2007 during growing season. Results of these field experiments showed that the average rapeseed yield increment resulting from 100 kg K ha-1 application was 358 kg ha-1, an increase over the control CK （no K） of 18.0% in 2005/2006 and 2006/2007. The average internal use efficiency （IE） of K was higher in the CK treatment （21.9 kg grain, kg-1 K uptake） than in the ＋K （100 kg K ha-1） treatment （17.7 kg grain, kg-1 K uptake）. Winter rapeseed required 68.1 kg of K to produce 1 000 kg seed. The recovery efficiency of K fertilizer in rapeseed production averaged 39.3%. The K balance was negative, with an average net removal of 117.6 kg K ha-1 in the CK treatment annually, and 56.8 kg K ha-1 in the ＋K treatment. The results indicated that there was a significant negative relationship between yield increments by K application and soil available K content. Based on the relative yield of CK/＋K at 90% level, the critical level of soil available K （NH4OAc-extractable K） was 135 mg kg-1.

不同生态区冬油菜根系生长及碳氮积累分配特征

【目的】作物产量受到生态环境的显著影响。研究不同气候条件下冬油菜的产量形成机制,为冬油菜高产品种选育和高产栽培提供理论基础。【方法】选择高产油菜品种秦优1618(Q1618)、油菜材料QF1以及常规油菜品种中双11(ZS11),2020-2021年在黄淮地区(陕西永寿)和长江中游地区(湖北阳逻)分别进行大田试验,研究不同生态区3个不同品种冬油菜的生长发育和生理特性。【结果】不同生态区显著影响冬油菜根系生长特性、干物质积累分配和碳氮积累特征。两个生态区均以Q1618的根系生长最为旺盛,其根长在越冬期较ZS11和QF1分别平均提高了21.0%和6.0%。此外,在阳逻3个品种油菜花期的根系主要集中分布在土壤浅层(0-15 cm),永寿点主要集中分布在土壤深层(15-30 cm)。与ZS11和QF1相比,两个地点的Q1618油菜花期的深层根长、根表面积、根系平均直径、根尖数分别平均提高了138.1%、78.8%、24.2%、83.3%和104.8%、103.1%、44.2%、41.6%。油菜越冬期和花期根系生长与产量显著正相关,且在永寿点相关性更强;越冬期,黄淮产区油菜地上部干物质积累减缓,叶片氮含量降低,根部可溶性糖含量积累,各器官(根、茎、叶)中蔗糖、果糖含量整体表现为QF1>Q1618>ZS11,且该区各器官可溶性糖含量与产量正相关。长江中游产区冬油菜根茎叶基本处于同步生长期,其越冬期干物质积累量整体较黄淮产区提高3.0倍,而该区越冬期干物质积累与单株有效角果数显著正相关。抽薹期后,两个试验点均以Q1618的干物质积累量最大,永寿试验点冬油菜成熟期的干物质积累量和角果中的干物质分配比例提高,分别较阳逻点显著提高10.3%和39.0%。整体而言,长江中游产区提高了冬油菜单株有效角果数,但黄淮产区冬油菜通过提高每角粒数和千粒重,其实测产量(除ZS11受冻害严重减产外)较长江中游产区平均提高了21.1%。相关性分析也表明,永寿点油菜产量与每角粒数和千粒重显著正相关,阳逻点油菜产量与单株有效角果数显著正相关。【结论】长江中游地区通过促进油菜冬前生长,提高单株有效角果数。黄淮产区则通过适当控制越冬期油菜地上部营养体的生长,抽薹期后促进根和茎秆的干物质向籽粒分配来提高每角粒数和千粒重,有利于实现冬油菜高产。

油菜抗咪唑啉酮类除草剂基因BnALS1R等位基因特异PCR标记的开发与应用

油菜抗咪唑啉酮类除草剂基因BnALS1R是从抗性突变体M9中克隆获得,抗性基因BnALS1R与野生型基因BnALS1存在1处SNP,即乙酰乳酸合酶第638位丝氨酸残基被天冬酰胺酸替代。为获得油菜抗除草剂基因BnALS1R的分子标记,根据该处点突变,结合获得的BnALS3与BnALS1序列,开发30条等位基因特异PCR(allele-specific PCR,AS-PCR)引物,采用筛选出的3条AS-PCR引物在F2、BC1和BC2群体中进行PCR扩增。结果表明,该标记有效检测出群体中存在的3种基因型,其分离比分别为1∶2∶1、1∶1、1∶1,均遵循单基因遗传规律。应用该标记对获得的抗性恢复系进行PCR扩增,结果发现所有抗性恢复系均能扩增出抗性基因BnALS1R目的条带,表明3条标记引物可应用于抗性基因的检测。AS-PCR标记的获得将促进以抗性基因进行油菜抗除草剂分子标记辅助选择育种。

播种期降水偏多对油菜重要农艺性状和产量的影响

为了解播种期降水偏多对油菜产量的影响,选用10个国家区试高产优质油菜新品种,分析正常年份(2019/2020)与降水偏多年份(2020/2021)在长江中游11个生态点的重要农艺性状、产量、品质和抗性,评估2020/2021年减产原因。通过正常年份与渍害年份逐月降雨量、温度等气象数据变化与产量与农艺性状变化进行相关和回归分析,结果发现,即使在正常排灌情况下,灾害年份油菜产量显著下降,播种期平均推迟11.5 d,生育期缩短11.2 d,产量和产油量分别极显著下降21.8%和23.2%。其中油菜株高、单株有效角果数和收获密度分别下降9.2%、21.1%和6%,均达到显著或极显著水平,而含油量、芥酸、硫苷、千粒重、角粒数、菌核病病指等性状变化不显著。回归分析表明,10月降雨大幅增加、形成渍害是减产的直接原因,而次生灾害如降雨导致播期推迟、秋季气温偏低和冬季降水减少导致的间接影响更大,对减产的贡献分别达到25.4%、50.5%和33%。对10个品种的产量和产油量分析,耐渍品种的选择应综合考虑正常年份产量、耐渍指数和含油量等指标,其中H1951、越优577、9zyYP12等品种正常年份产油量比对照增产11%~16.5%,灾害年份比对照增产5.4%~18.4%,生产上在做好开沟降渍的同时,抢播早播并增加密度可有效提高产量,有利于最大程度减轻灾害损失。

油菜乙酰乳酸合酶突变体S638N的酶学特性及其对ALS类除草剂的抗性

在对油菜抗咪唑啉酮类除草剂基因Bn ALS1R克隆与功能验证基础上,为比较抗性基因编码的乙酰乳酸合酶突变体S638N酶学特性及其对ALS类除草剂抗性与野生型的差异,构建基因原核表达载体,在大肠杆菌中表达S638N和野生型的重组融合蛋白。SDS-PAGE和Western blot分析表明,S638N和野生型均能表达出约74 k D的特异性重组蛋白。纯化目的蛋白,在不同温度和pH条件下,测定S638N和野生型的酶活性。结果显示,温度和pH对突变酶活性的影响与野生型相同,表现为先升后降,在37℃、pH 7.0条件下催化活性均最高。同时,该突变酶的酶学动力学参数Km和Vmax与野生型没有显著差异,其对3个辅助因子的响应曲线也与野生型类似,缺少其中任何一个辅助因子均使突变酶S638N基本都没有活性。然而,突变酶S638N对IMI类除草剂抗性显著高于野生型,而对Su类除草剂敏感性和野生型相同。因此,突变酶S638N具有对IMI类除草剂的专一抗性,但未改变酶学反应特征。

甘蓝型油菜木质素合成关键基因F5H、4CL和COMT的定量表达

以甘蓝型油菜(Brassica napus L.)抗倒伏品种浙平1号和易倒伏品种高芥1号为材料,采用荧光定量PCR方法对木质素合成关键基因F5H(阿魏酸-5-羟基化酶)、4CL(4-香豆酸CoA连接酶)和COMT(咖啡酸/5-羟基阿魏酸-O-甲基转移酶)在薹期和角果期根颈部、茎部的相对表达量进行了分析。结果显示,F5H在薹期和角果期根颈部的相对表达量,易倒伏材料高于抗倒伏材料;茎部的相对表达量,抗倒伏材料高于易倒伏材料。4CL和COMT基因在薹期根颈部、茎部和角果期根颈部的相对表达量,易倒伏材料高于抗倒伏材料;角果期茎部的相对表达量,抗倒伏材料显著(P<0.05)高于易倒伏材料。结果表明,油菜角果期茎部木质素合成关键基因F5H、4CL和COMT的相对高量表达可能有助于增强植株的抗倒伏能力。

特早熟春性甘蓝型油菜sBnFLD基因的克隆及表达

【目的】克隆特早熟春性甘蓝型油菜A基因组上的sBnFLD基因,并对其进行表达研究,为该基因的功能及其在成花转变中的作用研究奠定基础。【方法】根据GenBank中已报道的拟南芥和白菜型油菜FLD同源基因的保守序列设计引物,采用PCR和RT-PCR扩增特早熟春性甘蓝型油菜86号品系(光周期不敏感)的FLD同源基因,用qRT-PCR技术检测sBnFLD基因在86号品系不同发育时期茎、叶和茎尖中的表达情况。【结果】克隆出了sBnFLD基因,命名为sBnFLD,在GenBank中的登录号为KR003079.1。sBnFLD基因cDNA全长2 376bp,有3个内含子,4个外显子,编码791个氨基酸残基,分子量86.5ku,等电点8.5;sBnFLD为非分泌蛋白和非膜蛋白;sBnFLD蛋白N端有2个保守的结构域α螺旋结构域(SWIRM)和NAD(P)-binding-8结构域,该蛋白有多个α螺旋和β折叠。生物信息学分析显示,sBnFLD蛋白与已报道的甘蓝型油菜未知蛋白(CDX73929.1)和电子克隆的白菜型油菜FLD(XP_009135110.1)氨基酸序列相似性达99%,与拟南芥FLD氨基酸序列相似性达87%。qRT-PCR分析结果显示,sBnFLD基因在油菜苗期和现蕾初期茎、叶、茎尖中均有表达,但在蕾期茎尖中表达量最高。【结论】克隆出的sBnFLD基因为甘蓝型油菜的FLD同源基因,该基因在春性特早熟甘蓝型油菜开花调控中可能起着重要的调节作用。

北方寒旱区甘蓝型冬油菜的春化特性与抗寒性

【目的】研究甘蓝型冬油菜春化特性与抗寒性的关系,为超强抗寒甘蓝型冬油菜品种的选育和抗寒性评价提供理论依据。【方法】以强冬性品种16-2444、17-2251,冬性品种天油14号、天油2238,弱冬性品种甘杂9号、秦早1号等6个甘蓝型冬油菜品种为材料,通过春播,测定春化率、株高标准化值,分析春化特性;秋播冬前测定株高、根长、根颈直径、生物量,并统计越冬率,同时结合低温发芽试验,利用抗寒系数和综合抗寒系数对品种抗寒性进行评价,利用相关性分析研究品种春化特性与抗寒性之间的关系。【结果】6个甘蓝型冬油菜越冬率为20.9%~74.4%,根颈直径为10.7~18.0 mm,根鲜质量为9.3~23.2 g/株;4℃发芽率为26.4%~56.4%,各品种发芽率由高到低依次为17-2251>16-2444>天油14>天油2238>甘杂9号>秦早1号。6个甘蓝型冬油菜春播的春化率为0~79.3%;株高标准化值为0.017~0.892,其变化趋势由高到低依次表现为秦早1号、甘杂9号>天油2238>天油14号>16-2444>17-2251。通过计算综合春化系数和综合抗寒系数对其抗寒性进行综合评价,其中17-2251和16-2444为抗寒性品种,天油14号和天油2238为弱抗寒性品种,甘杂9号和秦早1号为不抗寒品种。相关性分析结果表明,综合抗寒系数与越冬率、根颈直径、4℃发芽期抗寒系数、根鲜质量呈极显著正相关关系,与地上部鲜质量、地上部干质量、根干质量呈显著正相关关系,与春播综合春化系数、春化率、株高标准化值呈显著或极显著负相关关系。【结论】强冬性品种16-2444和17-2251可在北方寒旱区种植,越冬率、低温冻害前根颈直径大小、根鲜质量、4℃发芽率、春播春化率是北方地区强抗寒性甘蓝型冬油菜新品种选育和抗寒性评价的可靠指标。