甘蓝型油菜脂肪酸碳链延长酶BnaA.FAE1与BnaC.FAE1的底物特异性分析

为提供信息改良油料种子脂肪酸,研究脂肪酸碳链延长酶1（FAE1）的底物特异性,将甘蓝型油菜A、C基因组的BnaA.FAE1和BnaC.FAE1分别在亚麻荠种子中表达。其转基因种子中山嵛酸与芥酸含量的比值（C22:0/C22:1）分别为0.18和0.88,表明BnaA.FAE1对单不饱和脂肪酸亲和力较高,而BnaC.FAE1则对饱和脂肪酸亲和力较高,这种差异在各转基因世代表现稳定。通过分析T3转基因家系种子中酰基辅酶A（Acyl-CoAs）的组成,进一步证明了上述结论。但是在拟南芥中分别异源表达上述基因,并没有观察到类似的底物特异性差异。在甘蓝型油菜祖先种,白菜型油菜和甘蓝种子中调查其C22:0/C22:1比值,同样未发现其FAE1底物特异性存在差异。综上认为BnaA.FAE1和BnaC.FAE1在亚麻荠中存在底物特异性。     

植物芥酸合成代谢与遗传调控研究进展

芥酸是十字花科植物种子中特异积累的长链脂肪酸,是目前油菜品质育种的重要对象之一.FAE1基因是控制芥酸合成的关键基因.由FAE1基因编码的β-酮酯酰-CoA合酶(KCS)是芥酸合成的限速酶.目前发现的FAE1基因在植物中高度同源,只含一个开放阅读框,长度为1521bp左右,不含有内含子.目前的低芥酸油菜品种主要来自ORO低芥酸血缘,其低芥酸特性是由于高芥酸品种FAE1基因的点突变造成的,导致编码的蛋白质在282位上的氨基酸产生差异,高芥酸品种中是丝氨酸,低芥酸品种中是苯丙氨酸.卢长明等在我国双低油菜品种中发现并克隆获得一种新型FAE1基因,标志着在国际上找到第二个低芥酸基因源.对FAE1基因的深入了解使得从分子水平培育高芥酸和低芥酸品种成为可能.     

湘油5号油菜芥酸含量的基因分析

为了弄清控制中国甘兰型油菜芥酸含量的基因数目,每个芥酸基因即携带芥酸的量,以及它与欧洲类型油菜的等位关系,特进行了湘油5号芥酸含量的基因分析试验。试验结果表明:(1)湘油5号油菜芥酸含量受两对基因控制,每个芥酸基因即携带芥酸的量为12％     

大豆子叶互生突变体的发现

大豆品种N8855种子浸种后播于消毒土的盆钵内,置于无光照的生长箱内,生长温度为29℃,于第8天发现-株突变体(M0)子叶表现互生现象,而其余植株子叶表现对生(图A)。此株子叶互生突变体(M0)的M1株系置光照培养箱是生长,同N8855一样表现子叶对生;而经暗室诱导子叶表现互生,植株其余性状同于N8855(图B)。M2代表现同M1一致。这一经暗诱导表现子叶互生现象在双子叶植物上是首例报道。 　　大豆正常子叶对生情况下,位于子叶节以下的茎状轴称为下胚轴,子叶节至第一对真叶节部分称为上胚轴;暗诱导的子叶互生突变体,其发育的组织结构变得复杂,正常对生子叶节拉开,两片子叶的节间可能为中胚轴,而中胚轴在禾本科植物中常见、在双子叶植物未见报道     

花生种子萌发过程中内源激素含量的变化

种子的休眠和萌发是植物生活史重要的两个环节,植物激素在其中起到关键的调节作用。本研究利用ELISA方法测定了弱休眠性花生品种Chico(CC)和强休眠性丰花1号(FH1)花生种子在萌发过程不同部位中脱落酸(ABA)、赤霉素(GA3)、油菜素内酯(BR)和吲哚乙酸(IAA)的含量。结果表明,FH1新鲜收获种子和干种子中不同部位ABA含量水平明显高于CC;吸水萌发过程中,两品种子叶中ABA含量和ABA/GA3比例变化趋势呈现明显差异,但两品种整体ABA含量及ABA/GA3比例随吸胀降低。研究表明,ABA在检测的三个部位中均发挥作用。萌发中后期,两品种子叶中GA3含量上升,表明GA3主要在子叶发挥作用。两品种IAA及BR含量在种子萌发过程变化趋势一致,它们主要在胚轴及胚根发挥作用。新鲜种子中IAA含量较高,吸胀后呈"波浪型"变化趋势,总体维持明显低于新鲜收获的种子中的水平;且FH1中IAA含量水平明显低于CC品种。萌发过程中两品种BR含量整体呈上升趋势,FH1的BR含量明显高于CC种子。总之,不同品种间内源激素含量水平存在差异,FH1中较高的ABA水平与其较强的休眠性有关;萌发过程中GA3、BR的提高和较低的IAA水平促进胚轴伸长及胚根生长。     

甘蓝型油菜Δ9硬脂酰ACP脱氢酶（SAD)基因的克隆与表达分析

为改良甘蓝型油菜菜籽油脂肪酸的组分,根据拟南芥Δ9硬脂酰ACP脱氢酶（SAD)核酸序列特征,检索白菜全基因组SAD基因和cDNA的可能序列,通过同源序列法克隆获得6个甘蓝型油菜SAD基因。比对结果显示,这6个基因编码的氨基酸序列同源性达53.2%~96.3%。系统进化分析显示,甘蓝型油菜SAD基因与蓖麻、大豆、芝麻、葵花等6个油料作物SAD基因的序列相似性很高,甘蓝型油菜与这些高等植物的SAD基因在进化上具有较高的保守性。本文还对4个甘蓝型油菜SAD基因BnSAD1:1、BnSAD2:1、BnSAD2:2和BnSAD2:3进行了表达模式分析,发现它们在种子发育过程中表达,并且都在40d的种子中表达量达到最高值,推测这4个基因均参与了硬脂酰ACP (C18:0-ACP)脱氢生成油酰基ACP(Δ9C18:1-ACP)的过程,尤其是BnSAD2:3可能为种子特异表达基因。     

红麻、苘麻的子叶、叶序与花瓣旋向

红麻和茼麻都是双子叶植物。种子里的两片子叶呈重叠摺曲状态，包着胚芽、胚茎，一片子叶稍外而偏大，另一片子叶靠内而略小。当红麻种子发芽出土后，稍外的一片子叶明显较大，基部两侧叶缘微有突出，另一片靠内的子叶则较小，基部两侧叶缘无明显突出(见图1)。     

单基因控制白菜型油菜种皮颜色和下胚轴颜色

用绿色下胚轴、黄籽材料与早花野生类型品系和品种Torch杂交,调查白菜型油菜(Brassica campestris L.)下胚轴和种皮颜色的关系,发现下胚轴颜色和种皮颜色存在着完全相关。该研究与单隐性基因控制下胚轴和种子色素产生的假说相一致,并对培育白菜型黄籽油菜进行了讨论。 白菜型油菜种皮颜色遗传的研究表明:种皮颜色受一至三对独立基因控制(Ahmed和Zuberi,1971;Mohammed,1942;Stringam,1980)。最近对四个品种的研究表明:种皮颜色受两对独立显性基因Br_1和Br_3控制(Stringam,1980)。     

UV-A辐射对大豆芽苗菜中抗坏血酸含量的影响

以黑暗培养为对照,以白光、红光、蓝光、黄光、UV-A和UV-B为处理,研究了不同光质对大豆芽苗菜生长和抗坏血酸含量的影响。结果表明:与对照相比,光照处理显著降低了大豆芽苗菜下胚轴的长度(白光除外),且显著提高了下胚轴和子叶中抗坏血酸含量。与其它光质处理相比,UV-A连续光照36 h后,下胚轴和子叶中抗坏血酸含量提高最显著。进一步着重研究了UV-A的调节机理,与对照相比,UV-A连续光照36 h后,大豆芽苗菜子叶中谷胱甘肽含量显著升高,下胚轴和子叶中DHAR、GR酶活性及其基因的相对表达量均显著提高。综上所述,光照有利于大豆芽苗菜中抗坏血酸含量的积累;UV-A可能是通过提高DHAR、GR酶活性及基因的表达量显著提高抗坏血酸的含量。     

RNAi干扰油菜Δ12-脂肪酸脱饱和酶基因的表达效果

为进一步研究RNAi介导的Δ12-脂肪酸脱饱和酶（FAD2）干扰基因对油菜内源FAD2基因表达的影响,以油菜肌动蛋白(β-Actin)基因为内参照基因,提取转基因油菜幼嫩种子总RNA,通过半定量RT-PCR检测内源FAD2基因的相对表达量。结果表明,T1,T3代转基因种子中FAD2基因的相对表达量与对照相比明显降低。对T3代种子的油酸含量的分析表明：转基因油菜种子中油酸的含量比野生型增加了13.90到32.20个百分点,直接说明RNAi干扰体下调了FAD2基因的表达。因此,种子内源表达的FAD2基因被RNAi干扰体有效沉默,并且产生了能够稳定遗传两代的表型变化。     

种子芥酸和硫苷含量对甘蓝型油菜遗传转化的影响

选取低硫苷低芥酸含量的甘蓝型油菜品种“湘油15号”和“Westar”,高硫苷高芥酸含量的甘蓝型油菜品系“GX-272”和“GX29”,利用农杆菌介导法,以pFGC5941为目标载体,分别对其进行遗传转化。以磷化麦黄酮（PPT）作为筛选剂,分别对4个油菜品种（系）的子叶柄分化率和转化率进行统计。结果表明,双低油菜“湘油15号”、“Westar”的子叶柄分化率高于高硫苷高芥酸油菜“GX-272”和“GX29”;而高硫苷高芥酸油菜“GX-272”和“GX29”的转化率则高于双低油菜“湘油15号”、“Westar”。初步认为种子中硫苷和芥酸含量对甘蓝型油菜子叶柄遗传转化的分化率和转化率有一定影响。     

花生脂肪酸延长酶基因ＡｈＦＡＥ１及其启动子的克隆与功能分析

为探讨花生脂肪酸中低芥酸含量的原因,从花生中克隆了脂肪酸延长酶FAE1及其启动子序列,并进行了功能分析。结果表明,AhFAE1全长cDNA为2 202bp,含有441bp的5?非翻译区及201bp的3?非翻译区,编码蛋白含519aa,分子量58.17Da,理论等电点9.15,AhFAE1与麻疯树（Jatropha curcas ALB76796.1）、黄麻（Corchorus capsularis OMO87584.1）、拟南芥AtKCS4亲缘关系较近。亚细胞定位结果显示AhFAE1定位于内质网。qRT-PCR结果显示,AhFAE1在各个组织中均有表达,在种子中随着种子的发育成“钟”型变化,花后60d表达量最高。构建了植物表达载体,通过农杆菌介导法转化拟南芥研究启动子功能,利用GUS组织化学染色研究其表达特征,在任何组织中未发现GUS活性。推测AhFAE1可能参与了花生长链脂肪酸的合成,但是该基因启动子转录活性弱可能是造成花生中低芥酸含量的主要原因。      

大豆原生质膜及混合细胞器膜脂脂肪酸对干旱胁迫的反应

本文分析了大豆复叶、真叶、子叶和发育子叶原生质膜及混合细胞器膜脂脂肪酸的组成、配比以及脂肪酸不饱和指数对干旱胁迫的反应。研究结果表明:大豆原生质膜及混合细胞器膜脂中主要有六种脂肪酸:豆蔻酸、棕榈酸、硬脂酸、油酸、亚油酸、亚麻酸,还有少量的月桂酸和花生酸和一种未标记的脂肪酸。干旱胁迫不改变大豆不同叶类组织原生质膜和混合细胞器膜脂脂肪酸的组成,但配比和组分含量却发生了很大变化。脂肪酸组分中变化最显著的是亚麻酸,其次是亚油酸和棕榈酸。亚麻酸与脂肪酸不饱和指数呈极显著的正相关。耐旱型品种(庆选101)膜脂对干旱的反应,为脂肪酸的饱和化作用较慢,不饱和脂肪酸含量高于不耐旱品种(黑农11)。同一品种不同叶类对干旱的抗性表现的顺序为:复叶>真叶>发育子叶>子叶。     

Vernonia galamensis,a natural source of epoxy oil: variation in fatty acid composition of seed and leaf lipids

Vernonia galamensis is a new potential industrial oilseed crop with origin in East Africa. The seed oil has unique chemical and physical properties, that will permit its use in the formulation of reactive diluents, products to serve as solvents that become part of the dry paint surface and do not evaporate to pollute the air. A collection of 41 accessions was evaluated for seed and leaf fatty acid composition. In the seed, vernolic acid (C18:10) varied from 54 to 74%, and linoleic acid (C18:2) from 3 to 32%. In the leaf linolenic acid (C18:3) varied from 41 to 59%, palmitic (C16:0) from 12 to 22% and C18:4 from 8 to 17%. Correlation analysis between the seed fatty acids showed that vernolic acid is negatively correlated with C16:0, C18:0, C18:2, C18:3. In the leaf, negative correlations between C18:3 and the other leaf fatty acids were observed. C18:2 and C18:3 showed negative and positive correlations, respectively between the leaves and the seed. In general, there is a wide range of fatty acid composition specially vernolic and linolenic acids in the seed and in the leaf, respectively which might indicate the potential for oil quality improvement of V. galamensis.     

Responses of Seed Yield and Quality to Nitrogen Application Levels in Two Oilseed Rape (Brassica napus L.) Varieties Differing in Nitrogen Efficiency

Abstract

The relationship between nitrogen efficiency (NE), defined as seed yield per unit nitrogen (N) application, and seed quality was examined in two oilseed rape (Brassica napus L.) varieties at 5 N application levels, 0.6, 3, 6, 12, 15 mmol L?¹, N₁, N₂, N₃, N₄ and N₅, respectively. Seed yield, oil yield and protein content were increased with the increase in N application level, but NE and oil content were decreased, and the fatty acid composition in seed was hardly changed. Analysis of seven fatty acids revealed aslight decrease in the contents of erucic acid and arachidonic acid with the increase in N application level, but no obvious change in the contents of palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid. Compared with the low NE variety H29, the seed yield and contents of erucic acid and arachidonic acid in the high NE variety bin270 were more markedly increased with the increase in N application level, and the oil content was hardly changed. The seed yield, oilcontent and oil yield were higher in the high NE variety than in the low NE variety at all 5 N application levels. There were no significant differences in protein, palmitic acid, stearic acid and oleic acid contents between the varieties at any of the 5 N application levels, but there were slight differences in the linoleic acid and linolenic acid contents between the two varieties. In brief, N application improved oil yield more greatly in the high NE variety than in the low NE variety, but hardly affected the fatty acid composition. Therefore, the seed quality and oil content of oilseed rape may not be decreased by breeding of a high NE variety with a high N absorption efficiency and high N use efficiency.     

Lipase mediated hydrolysis of Mimusops elengi and Parkinsonia aculeata seed oils for the determination of positional distribution of fatty acids

Two medicinally important seed oils viz. Mimusops elengi and Parkinsonia aculeata were analyzed for fatty acids distribution pattern in triacylglycerols using pancreatic lipase hydrolysis method. The seed oils contain high percentage of unsaturated acids (M. elengi 64.8% and P. aculeata 82.7%). The lipolytic data revealed that linoleic acid dominates at 2-position of triacylglycerols of all seed oils. M. elengi contain erucic acid in small amount (0.3%).     

Breeding prospects of Lunaria annua L.

Lunaria annua is a biennial cruciferous oil seed crop. The seeds contain 30–35% oil, which consists of 67% long chain fatty acids (44% erucic acid, C22:1, and 23% nervonic acid, C24:1). The oil is suitable as lubricant. In addition, recent developments indicate that nervonic acid may be used as raw material for the production of a medicine against multiple sclerosis. The biennial character of Lunaria is a main constraint for an economically feasible production of Lunaria oil. The crop has to be sown early in the summer to achieve vigorous plant development required for vernalization during the winter. It would be a great advance when Lunaria could be sown later in the summer after an early harvested crop. From 1993, breeding research in Lunaria has been performed at CPRO-DLO, Wageningen, The Netherlands. A collection of 76 accessions was maintained and evaluated for agronomic performance. In 1995, a selection of 24 accessions were sown at four sowing dates, from end June until end of August and in 1996, 12 promising accessions were sown again at 15 and 30 July. Three accessions showed suitability for delayed sowing until beginning of August. Delay in sowing time caused also delay of flowering and seed ripening. Seed yield amounted to 1200 kg/ha in 1996 and 1700 kg/ha in 1997. Seed oil content varied from 30–38%. Severe infection of Albugo candida and Alternaria occurred and might have reduced seed yield in both years. Most accessions sustained severe winter frost of−17°C very well. It is concluded that within the evaluated gene pool promising variation is available to select for ability for late sowing, to improve the disease resistance and to increase seed yield and seed oil content.     

Novel seed oil types of Ethiopian mustard with high levels of polyunsaturated fatty acids

Oils rich in polyunsaturated fatty acids linoleic acid and linolenic acid have important industrial applications, both as drying oils in the manufacture of paints and coatings as well as in formulation of pharmaceuticals and nutraceuticals. However, no oil types with high levels of polyunsaturation have been developed so far in Brassica oilseed crops. The objective of the present research was to select for high levels of linoleic acid and linolenic acid in Ethiopian mustard (Brassica carinata A. Braun). Selection started from the F₃ (S₀) seed generation of crosses involving the high oleic acid, high erucic acid line N2-3591, the low linolenic, high erucic acid line HF-186, and the zero erucic acid line 25X-1. The analysis of individual S₀ seeds showed ranges of variation with maximum levels of 68.9% linoleic acid and 36.4% linolenic acid. Selection for increased levels of linoleic acid resulted in a S_1:2 high linoleic acid line BC-HL that showed average linoleic acid contents of 62.5%, 58.3%, and 59.6%, respectively in three contrasting environments, compared to 47.8%, 45.8%, and 52.1%, respectively in a high linoleic acid check line. Selection for increased levels of linolenic acid resulted in a S_1:2 high linolenic acid line BC-HLN that showed average linolenic acid contents of 27.1%, 25.8%, and 26.3%, respectively in the mentioned environments, compared to 23.9%, 21.2%, and 19.4%, respectively in a high linolenic acid check line. Both lines developed in the present research possess novel fatty acid profiles not available so far in Brassica oilseed crops and they may contribute to broaden the potential of Brassica oils for industrial applications.