红花油酸去饱和酶基因的克隆及序列分析

【目的】对红花油酸去饱和酶FAD2基因进行克隆和生物信息学分析,为深入研究该酶的功能提供理论依据。【方法】提取红花种子总RNA,通过RT-PCR方法进行反转录,PCR扩增得到FAD2基因全长cDNA序列。运用生物信息学方法,对红花FAD2氨基酸序列的理化性质、系统进化、蛋白定位和跨膜区域等进行预测和分析。【结果】成功克隆获得了红花FAD2基因,其开放阅读框cDNA长1 140bp,编码380个氨基酸,预测分子质量43.6ku,理论等电点8.37,带有正电残基(强酸性)30个、负电残基(强碱性)34个。FAD2蛋白含有3个极度保守的His-Box,不存在明显的信号肽,存在6个跨膜结构域,与疏水区域预测结果一致。红花FAD2核苷酸的分子进化树分析显示,其与日本栽培稻的亲缘关系较近。红花FAD2氨基酸序列比对结果表明,不同植物的FAD2具有较高的同源性,同源性平均达72.94%。【结论】成功克隆了红花FAD2基因,并对其编码的蛋白进行了生物信息学分析。     

Combining ability for main quality traits in peanut (Arachis hypogaea L.)

High-oleic peanuts has been recognized by processing sectors, seed sellers and consumers for their longer shelf life, longer seed life and mutiple healthe benefits. High oleate is becoming a requisite ​for varietal releases in many peanut breeding programs at present. To select desirable parents for high-oleic peanut breeding, the study was conducted to evaluate the combining ability of 5 high-oleic donors from our research team, based on quality of individual single seeds. General combining ability was significant for oleic, linoleic, stearic and palmitic acid, oil and protein, while specific combining ability was significant for the traits except oil. Among them, oil content was found to be conditioned solely by additive gene actions, and for other quality traits, additive gene effects were more important than non-additive gene effects. High-oleic CTW and normal-oleic Xiaojingsheng were selected as the best general combiners for peanut oleic acid improvement. Narrow-sense heritability was high for quality traits other than protein, suggesting that there was high potential for genetic improvement in these traits.     

Effect of variety and seed dressing on emergence of high-oleic peanut under low temperature and high soil humidity conditions

Low temperature coupled with high soil moisture during sowing to emergence generally results in poor peanut stand, thereby posing a non-negligible threat to peanut production in north and northeast China. Five high-oleic (HO) peanut cultivars and 4 seed dressing treatments capable of controlling several diseases and insect pests along with untreated checks were used to find the best combinations to cope with the dual stresses during sowing to emergence period. High broad-sense hereditability estimates of seedling emergence indicated great potential for genetic improvement of this trait. Analysis of variance in the split-plot experiment showed that the main effects of variety and seed dressing and their interaction on seedling emergence were significant. Seed dressing treatments increased seedling emergence percentage by 2.09–35.00 percent points. Four of the 5 HO peanut cultivars yielded satisfactory results. For Huayu 665, Huayu 668 and Huayu 965, Huweisanbao may be the best option; for Huayu 962, Weilidan was highly acceptable. These combinations will be evaluated further in multiple environments before large-scale extension.     

Characterization of carotenoid pigments and their biosynthesis in two yellow flowered lines of Sandersonia aurantiaca (Hook)

The basis of the novel cream/yellow flower color found in two Sandersonia aurantiaca lines was examined as part of a project to develop new colors for this cut flower crop in New Zealand. The original color, bright orange, is due to the accumulation of the carotenoid pigments zeaxanthin and β-cryptoxanthin. The cream/yellow lines have much lower levels of total carotenoid pigments (17% and 21%) in their tepal tissue compared to the wild type progenitor. Microscopic analysis of epidermal cells showed alteration in the pigment cluster bodies of tepal tissue of the cream/yellow lines compared to the orange wild type. HPLC analysis of the pigments showed that one cream/yellow line (Y-H) produced the same pigment profile as the wild type (zeaxanthin and β-cryptoxanthin). In comparison, the other cream/yellow line (Y-S) produced the carotenoid profile normally found in green vegetative tissue (β-carotene and lutein). Analysis of carotenoid biosynthetic gene expression in Sandersonia indicated that the cream/yellow Y-H line showed expression patterns similar to the wild type, and gene expression in the Y-S line is decreased relative to the wild type and the Y-H line. This revised version was published online in July 2006 with corrections to the Cover Date.     

Allelic Variation at the TaZds-A1 Locus on Wheat Chromosome 2A and Development of a Functional Marker in Common Wheat

ζ(zeta)-carotene desaturase (ZDS) is a key enzyme for carotenoid biosynthesis,demonstrating high association with the yellow pigment (YP) content in wheat grain.Cloning ZDS gene and developing function...     

甘蓝型油菜油酸脱氢酶基因(fad2)多个拷贝的发现及分析

以甘蓝型油菜湘油15为材料, 随机挑选56个来自基因组的fad2基因克隆、47个来自幼苗整株的fad2基因cDNA克隆和9个授粉27 d后种子中fad2 cDNA克隆进行双向测序。基因组中56个fad2序列的碱基同源性为91.0%~99.9%, 从中得到11个差异序列, 即11个不同的fad2基因拷贝。将其翻译成氨基酸序列发现, 6个拷贝在编码区中出现多个终止密码子, 另外5个的同源性为90.60%~99.74%, 与47个来自幼苗整株的fad2基因cDNA序列进行比较, 发现fad2基因没有内含子。从种子中的9个fad2 cDNA克隆序列中找到2个有差异的cDNA, 它们的编码区中没有终止密码子, 说明在种子中有多个fad2基因表达。基因组中的11个拷贝根据同源性可分成两组, 命名为fad2I和fad2II。RT-PCR分析发现在授粉27 d的种子中fad2I有较强表达, fad2II没有表达; 但在叶片中两者都有表达。     

Inventory of Fatty Acid Desaturases in the Pennate Diatom Phaeodactylum tricornutum

The diatom Phaeodactylum is rich in very long chain polyunsaturated fatty acids (PUFAs). Fatty acid (FA) synthesis, elongation, and desaturation have been studied in depth in plants including Arabidopsis, but for secondary endosymbionts the full picture remains unclear. FAs are synthesized up to a chain length of 18 carbons inside chloroplasts, where they can be incorporated into glycerolipids. They are also exported to the ER for phospho- and betaine lipid syntheses. Elongation of FAs up to 22 carbons occurs in the ER. PUFAs can be reimported into plastids to serve as precursors for glycerolipids. In both organelles, FA desaturases are present, introducing double bonds between carbon atoms and giving rise to a variety of molecular species. In addition to the four desaturases characterized in Phaeodactylum (FAD2, FAD6, PtD5, PtD6), we identified eight putative desaturase genes. Combining subcellular localization predictions and comparisons with desaturases from other organisms like Arabidopsis, we propose a scheme at the whole cell level, including features that are likely specific to secondary endosymbionts.     

Effects of dietary alpha‐linolenic acids on growth performance,lipid metabolism and antioxidant responses of juvenile Russian sturgeon Acipenser gueldenstaedtii

Five isonitrogenous diets were formulated with graded alpha‐linolenic acid (LNA) levels (0, 5, 10, 15 and 20 g/kg) to investigate LNA requirement of juvenile Russian sturgeon Acipenser gueldenstaedtii. Weight gain and specific growth rate of fish fed LNA5 and LNA10 were significantly higher than those in other groups, while the feed conversion ratio of these two groups was lower than others. Dietary LNA increased n‐3 polyunsaturated fatty acid and n‐3/n‐6 ratio, but decreased saturated fatty acid contents in the liver. DHA in the fish tissue also increased with the increased dietary LNA. The superoxide dismutase activity was highest in fish fed LNA5. Fish fed LNA10 showed the highest catalase activity and the highest malondialdehyde content. A 459‐bp fragment of Δ6 fatty acid desaturase and a 474‐bp fragment of elongases of very long chain fatty acids 5 were cloned and analysed. The expressions of these two genes were higher in fish fed LNA15 and LNA20. The highest hepatic lipase activity occurred in fish fed LNA 20, and the malate dehydrogenase activity peaked in the LNA5 group. Based on SGR and FCR, the range of optimum dietary LNA concentration for juvenile Russian sturgeon is recommended at 6.85–10.69 g/kg.