芝麻种质资源及相关分子生物学研究进展

芝麻是重要的优质传统油料作物,素有"油料皇后"的美称。我国拥有丰富的芝麻种质资源,深入研究、评价和有效利用芝麻种质资源是保护其遗传多样性、拓宽遗传基础进而提高芝麻产量和品质的关键。本文对芝麻种质资源的收集保存、鉴定评价、利用现状、品种选育概况及相关分子生物学研究进展进行综述,期望能对芝麻遗传及应用研究提供一些参考。     

Comparative Analysis of Root Transcriptome Profiles of Sesame (Sesamum indicum L.) in Response to Osmotic Stress

Journal of Plant Growth Regulation - Sesame (Sesamum indicum L) is a high-value oilseed cash crop grown across different geographies. Although sesame is traditionally considered drought-tolerant,...     

Development of polymorphic microsatellite markers in sesame (Sesamum indicum L.)

Fifty microsatellite sequences (SSRs) were isolated from an enriched library of sesame (Sesamum indicum L.) using a modified protocol. After screening, 10 polymorphic microsatellites were used to determine their usefulness in diversity analysis among 16 sesame accessions. The number of alleles ranged from three to six alleles per locus with an average of 4.6 alleles. The fragment size varied from 150 bp to 307 bp. Expected heterozygosites (H_E) and polymorphism information contents (PICs) ranged from 0.437 to 0.858 and 0.34 to 0.80, respectively, which indicates the highly informative nature of the microsatellites reported here. These microsatellite markers will be very useful in diversity analysis among a large germplasm collection of sesame present in our Korean gene bank and also in the establishment of its core collection.     

Genotypic effects on pollen morphology in sesame (Sesamum indicum L.)

Summary The morphology (shape, exine wall pattern, diameter, volume, surface area) of mature pollen grains from eight genotypes, four within each of two capsule types (dehiscent, indehiscent) was studied. The shape was a flattened sphere (oblate) with a P (polar axis diameter): E (equatorial axis diameter) ratio = 0.69. The exine wall pattern consisted of a series of furrows passing through the poles and intersecting the equatorial plane at right (90°) angles. In cross section, the furrows appeared to be associated with shallow U-shaped structures with the intine protruding between these structures. Over the eight genotypes, the diameter, volume, and surface area were 65 m, 147300 m³, and 13444 m², respectively. For all three related characters, highly significant differences between capsule type and genotypes within capsule type were obtained. For each character, the dehiscent capsule type mean was larger than the indehiscent capsule type mean with minimum overlap among the four genotype means within each capsule type. Possibly, the numerous and diverse pleiotropic effects associated with this simply-inherited recessive indehiscent capsule type character includes pollen dimensions.     

Ovicidal activity of Sesamum indicum (L.) oil against Spodoptera littoralis (Boisd.)

In the research for alternative tools and botanical products to control Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae). Sesamum indicum (L.) (Lamiales: Pedaliaceae) oil was assayed as an ovicide. The mortality increased with existence of fatty acids. Chemical analysis of S. indicum oil using GLC analysis showed palmitic acid as the major fatty acid (51.27%), while the major hydrocarbon and sterols were found to be heneicosane (58.63%) and β-sitosterol (2.60%), respectively. Generally, the values of LC₅₀s indicated that one-day-old egg masses are more susceptible than three-day-old eggs. Also, the leaf dip technique is more efficient than the spraying one. Results showed several features of chorionic surface deformation treated with sesame and KZ oils than control using scanning electron microscopy. Meanwhile, the tested oils caused significant reduction in both total soluble protein and transaminase enzymes as compared to control. Additionally, the oils elongated the incubation period and larval duration than control.     

A genetic linkage map construction for sesame (Sesamum indicum L.)

Sesame (Sesamum indicum L.) is one of the oldest oilseed crops with high seed oil quality. The first sesame genetic linkage map based on F2 segregating population of an intraspecific cross between two cultivars was constructed. Using three types of PCR-based markers, 284 polymorphic loci including 10 EST-SSR marker, 30 AFLP marker and 244 RSAMPL marker, respectively, had been screened. Subsequently, a total of 220 molecular markers were mapped in 30 linkage groups covering a genetic length of 936.72 cM, and the average distance between markers was 4.93 cM. In this map, the linkage groups contained from 2 to 33 loci each and ranged in distance from 6.44 cM to 74.52 cM. Based on map information, sesame genome length was estimated to be approximately 1,232.53 cM, and genome coverage of this map was about 76.0%. As a starting point of sesame genome study, the genetic linkage map will be hopeful to tag traits of breeding interest and further aid in the sesame molecular breeding. Furthermore, RSAMPL marker had been also appreciated in this paper, for its first usage in genetic map construction and higher utilization potential in some crop species lacking much genome information.     

In Vitro Multiplication of Sesame (Sesamum indicum) through Tissue Culture

Tissue cultures were established from different parts of sesame(Sesamum indicum L. cv. PT) seedlings. A callus tissue derivedfrom hypocotyl segments produced embryo like structures. Shoottips with cotyledons excised from 8 to 10-d-old seedlings producedmultiple shoot buds on a cytokinin-enriched medium. Presoakingand germination of seeds in BA or 2iP (8 mg l–1) enhancedthe development of shoot buds. Upon isolation and culture theshoots buds formed rooted plantlets in a charcoal-enriched medium. Sesamum, multiple buds, plantlets     

不同耐渍基因型芝麻在厌氧胁迫下根系的生理与结构变化

利用4种耐渍性不同的芝麻基因型,在厌氧胁迫条件下检测了根部无氧呼吸酶活性、内源乙烯含量并调查了根形态和解剖结构,以比较研究旱生植物耐渍性的主要机制。同时设计了田间分期多次淹水试验,观察早期淹水训练对芝麻生长和产量的影响。结果表明：耐渍种质的乙烯释放量在根中增加了6．06倍,茎中1．76倍,不定根数量增加了4．0～5．0倍,在初生根和不定根皮层形成典型的通气组织。非耐渍种质中未检测到乙烯变化,不定根数量增加了0．79～1．8倍,根中无明显的通气组织发生,但是乙醇脱氢酶(ADH)活性可增加4．2～9．3倍,高于耐渍种质。分期淹水试验以四对真叶期和初花期处理产量较高,与对照无显著差异,而终花期一次性淹水产量损失最大。综合分析认为,不定根增生和根皮层通气组织的形成是芝麻耐渍性的重要机制,根中内源乙烯的增加与结构适应变异有关。淹水训练能够有效地改善芝麻品种耐渍能力为结构适应提供了进一步的证据。     

Comparative Analysis of RAPD and ISSR Markers for Characterization of Sesame (Sesamum indicum L) Genotypes

The determination of genetic differences among crop genotypes has become the primary need to grant patent and the protection of Plant Breeder Rights (PBR). In the present study RAPD and ISSR markers were employed for the characterization of 16 sesame genotypes. Twenty six RAPD and 17 ISSR primers that generated clear and reproducible banding patterns amplified 194 and 163 bands, respectively among 16 sesame genotypes. Both RAPD and ISSR primers showed maximum discrimination power, and produced putative variety specific bands, which could be used for the identification of all the sesame genotypes, individually. However, only AG and CA based ISSR primers were found effective in the discrimination of genotypes. A poor correlation was observed between the matrices produced by RAPD and ISSR primers, which might be due to the array of different sites of the genome. Though, there was greater similarity among sesame genotypes (0.78 for RAPD and 0.71 for ISSR), the observed genetic diversity (0.22 for RAPD and 0.29 for ISSR), was found effective for the characterization of sesame genotypes. It is suggested that putative variety specific RAPD and ISSR markers could be converted to Codominant sequence characterized amplified region/sequence tagged site (SCAR /STS) markers to develop robust variety specific markers.     

Development and characterization of microsatellite markers in Indian sesame (Sesamum indicum L.)

The genetic characterization of Indian sesame cultivars and related wild species was analysed using 102 simple sequence repeat (SSR; microsatellite) markers. Of these, 62 were novel sesame-specific microsatellites isolated in the course of the present investigation by constructing genomic libraries. Characterization of the 68 sesame accessions and three related wild species using 72 polymorphic SSR primers resulted in the detection of 170 alleles. The number of alleles ranged from two to four with an average of 2.5 alleles per locus. Polymorphic information content of the markers ranged from 0.43 to 0.88 with an average of 0.66. UPGMA cluster analysis grouped all the accessions into two major clusters with a genetic similarity ranging from 0.40 to 0.91. A moderate to high level of genetic variability was observed. The three wild accessions used in the study formed separate clades and distant genetic relationships were observed between the cultivar lines and wild species. Differentiation of genotypes according to geographical region was not observed. Analysis of molecular variance (AMOVA) analysis revealed that a high percentage of variation was within populations (87.1 %). An overall F _st of 0.11 among the populations indicated low population differentiation. The SSR markers developed will be useful for further genetic analysis, linkage mapping and selection of parents in future breeding programmes.     

Transesterified sesame (Sesamum indicum L.) seed oil as a biodiesel fuel

The sesame (Sesamum indicum L.) oil was extracted from the seeds of the sesame that grows in Diyarbakir, SE Anatolia of Turkey. Sesame seed oil was obtained in 58wt/wt%, by traditional solvent extraction. The methylester of sesame (Sesamum indicum L.) seed oil was prepared by transesterification of the crude oil. Transesterification shows improvement in fuel properties of sesame seed oil. This study supports the production of biodiesel from sesame seed oil as a viable alternative to the diesel fuel.     

Effects of germination on chemical composition and functional properties of sesame (Sesamum indicum L.) seeds

The changes of chemical composition and functional properties of derooted sesame (Sesamum indicum L.) seeds (DSS) before, during, and after germination were investigated. Sesame seeds germinated in dark chambers maintained near 100% relative humidity at 35 degrees C without presoaking reached >99% germination rate in 4 days with the final moisture content stayed ca. 2% (w/w), characterizing sesame seeds as orthodox seeds that are suitable for long term storage at low temperature and humidity under defined environment. With noticeable reduction in fat content (23%), germinated DSS were found rich in linolenic acid, P, and Na, increasing from 0.38% (w/w), 445 mg/100 g, and 7.6 mg/100 g before germination to 0.81% (w/w), 472 mg/100 g, and 8.4 mg/100 g after germination, respectively. DSS after germination contained considerable amount of Ca (462 mg/100 g), higher than that of soybean. Germinated DSS presents an excellent source of sesamol (475 mg/100 g), a potent natural antioxidant, and alpha-tocopherol (32 mg/100 g), the most active form of vitamin E.     

Hepatoprotective Effect of Wheat-Based Solid-State Fermented Antrodia cinnamomea in Carbon Tetrachloride-Induced Liver Injury in Rat

Antrodia cinnamomea (A. cinnamomea) is an indigenous medical fungus in Taiwan and has multiple biological functions, including hepatoprotective and immune-modulatory effects. Currently, the commercially available A. cinnamomea are mainly liquid- and solid-state fermented A. cinnamomea. However, the hepatoprotective effect of solid-state fermented A. cinnamomea has never been reported. Here we evaluate the ability of air-dried, ground and non-extracted wheat-based solid-state fermented A. cinnamomea (WFAC) to protect against carbon tetrachloride (CCl₄)-induced hepatic injury in vivo. The results showed that oral administration of WFAC dose dependently (180, 540 and 1080 mg/kg) ameliorated the increase in plasma aspartate aminotransferase and alanine aminotransferase levels caused by chronic repeated CCl₄ intoxication in rats. WFAC significantly reduced the CCl₄-induced increase in hepatic lipid peroxidation levels and hydroxyproline contents, as well as reducing the spleen weight and water content of the liver. WFAC also restored the hepatic soluble protein synthesis and plasma albumin concentration in CCl₄-intoxicated rats, but it did not affect the activities of superoxide dismutase, catalase, or glutathione peroxidase. In addition, a hepatic morphological analysis showed that the hepatic fibrosis and necrosis induced by CCl₄ were significantly ameliorated by WFAC. Furthermore, the body weights of control rats and WFAC-administered rats were not significantly different, and no adverse effects were observed in WFAC-administered rats. These results indicate that WFAC is a nontoxic hepatoprotective agent against chronic CCl₄-induced hepatic injury.     

Global gene expression responses to waterlogging in roots of sesame (Sesamum indicum L.)

Waterlogging stress lowers yields in sesame (Sesamum indicum L.). A major component of waterlogging stress is the lack of oxygen available to submerged tissues. Although the morphology and physiology of plants grown under anaerobic conditions have been studied in detail, limited work has been done to elucidate adaptations at the molecular level. To gain comprehensive insight into how sesame responds to hypoxia at the genome level, we performed gene expression profiling at two time points during a 36-h period following hypoxic treatment using a whole-genome RNA-Seq analysis. We identified sets of significantly positively and negatively expressed genes (induced and repressed, respectively) in response to hypoxia with distinct temporal profiles. The genes that were affected were associated with glycolysis, nitrogen metabolism, starch and sucrose metabolism and plant hormone signal transduction and indicated the upregulation of particular pathways (glycolysis/glycogenesis) in the Kyoto Encyclopedia of Genes and Genomes. Moreover, significant changes in the expression of genes were found for pathways, including flavone and flavonol biosynthesis, steroid biosynthesis, photosynthesis, cysteine and methionine metabolism, glutathione metabolism, as well as phenylpropanoid biosynthesis, spliceosome, circadian rhythm. This study helps in elucidating the molecular mechanisms of waterlogging tolerance and provides a basis for the genetic engineering of sesame.     

Biological effects of low-energy C ion implantation on sesame (Sesamum indicum L.)

Field cultivation experiments on white sesame (Sesamum indicum L.)seeds implanted with low-energy C ion showed that different dosages of C ion implantation produce different biological effects.Sesame plants in 6 different dosage groups with C ion density respectively at 1×1011,1×1012,1×1015,5×1015,1×1016,5×1016 ion/cm2 were superior to the control group in plant height,leaf number,stalk diameter and leaf size.Further,sesame plants in these groups flower and seed earlier than those in the control group,and single plant yield also increased.Of all the groups,the 5×1015 ion/cm2 dosage group yielded the best effect,whereas the 1×1017/cm2 dosage group showed an evident inhibitory effect of ion implantation on the germination and growth of the sesame seeds.     

Hypoglycemic Effect of a Hot-water Extract from Defatted Sesame (Sesamum indicum L.) Seed on the Blood Glucose Level in Genetically Diabetic KK-Ay Mice

Genetically diabetic (type II) KK-A^y mice, male and 5 weeks of age, were divided into one group of 12 mice that were fed on a basal (BAS) diet and three groups of 6 mice each that were fed on the test diets for 4 weeks. Each test diet contained 4.0% of the hot-water extract (HES) from defatted sesame (Sesamum indicum L.) seed, 1.4% of the water eluent fraction (WFH) of HES or 0.7% of the methanol eluent fraction (MFH) of HES from a glass column packed with HP-20 resin. At the end of the feeding period, the BAS group was divided into the MAL and MALH groups which were respectively force-fed with 1 ml per mouse of a 20% maltose solution in water with or without 4.0% HES. The plasma glucose concentration and amount of urinary excreted glucose were lower from the HES and MFH diets than from the BAS and WFH diets. The levels of plasma glucose and serum insulin were lower in the MALH group than in the MAL group. These results indicate that HES and MFH had a reductive effect on the plasma glucose concentration of KK-A^y mice, and this effect is suggested to have been caused by the delayed glucose absorption.     

Control of hypocotyl gravitropism by photochrome in a dicotyledonous seedling (Sesamum indicum L.)

Abstract The present study was prompted by the question as to whether the strong effect of red and far-red light treatments on blue-light-mediated phototropism in the sesame (Sesamum indicum L.) hypocotyl (Woitzik & Mohr, 1988) should be attributed in part to changes initialed by light in the gravitropic counter-response. Light treatments, operating through phytochrome, do indeed strongly affect the gravitropic response. However, the direction of the light effect is the same in gravitropism, as in phototropism. Thus, the gravitropic counter-response leads to an underestimate, rather than an overestimate, of the importance of phytochrome action on phototropic responsiveness. The effect of red and far-red light, operating via phytochrome, on the gravitropic response of the sesame hypocotyl could be studied in the present paper without any interference due to phototropism or light control of longitudinal growth. It was found that the effects of red and far-red pretreatments (given prior to the onset of the stimulus) as well as the action of simultaneously applied red or far-red light (simultaneous to the phototropic or gravitropic stimulus) are very similar in both phototropism and gravitropism. In particular, the seedling is capable of superimposing information about the actual light conditions during bending on the ‘memory’ it has about the light conditions prior to the onset of phototropism or gravitropic stimulation, This striking similarity between the phototropic and gravitropic responses possibly indicates that phytochrome affects the signal-response-chain at a relatively late stage, after the phototropic and the gravitropic signal-response chains have merged. From a teleonomic point of view the action of red and far-red light on phototropic, as well as gravitropic, responsiveness can be conceived as part of a shade escape strategy.