甘薯生物技术研究进展

新兴的生物技术为甘薯这一古老的农作物带来了新的发展契机。细胞大规模培养、体细胞融合、基因转导等技术的研究和应用,可望从根本上改变甘薯传统的生产和育种模式。本文综合近年来国内外甘薯体细胞胚胎发生、原生质体培养和基因工程等方面的研究进展,对影响甘薯体胚发生体系及原生质体再生体系建立的诸多因素进行了详细论述,讨论了甘薯基因工程研究的应用潜力和目前存在的一些问题。     

西番莲生物技术研究进展(综述)

本文综述近年来西番莲组织培养、原生质体培养以及基因工程的研究进展,并提出应用前景。     

2,4 -D对甘薯体细胞胚胎发生的调控

将来源于‘徐薯18’叶片的胚性愈伤组织,接种在含有不同2,4-D浓度的液体MS培养基中进行悬浮培养,悬浮细胞表现出不同的形态结构、分裂方式和发育途径：2,4-D浓度为1 mg/L时,细胞均等分裂,增殖迅速;不含2,4-D时,细胞多进行不均等分裂,并发育成体细胞胚。不同2,4-D浓度中培养的悬浮细胞,其胞外过氧化物同工酶谱及其随时间变化的方式有很大差异,并与细胞的生长、发育过程密切相关。     

2，4_D对甘薯体细胞胚胎发生的调控

将来源于‘徐薯１８’叶片的胚性愈伤组织,接种在含有不同２,４Ｄ浓度的液体ＭＳ培养基中进行悬浮培养,悬浮细胞表现出不同的形态结构、分裂方式和发育途径：２,４Ｄ浓度为１ｍｇ／Ｌ时,细胞均等分裂,增殖迅速;不含２,４Ｄ时,细胞多进行不均等分裂,并发育成体细胞胚。不同２,４Ｄ浓度中培养的悬浮细胞,其胞外过氧化物同工酶谱及其随时间变化的方式有很大差异,并与细胞的生长、发育过程密切相关     

我国枣生物技术研究进展

生物技术的发展为枣种质资源的研究、创新及新品种培育提供了更多的途径。本文综述了近年来我国枣生物技术的研究进展,主要包括离体培养、分子标记、基因工程3个方面的内容。目前,生物技术是枣传统育种的有效补充,已成为枣遗传改良、种质资源创新和科学研究的重要技术。     

柑橘生物技术研究进展

综述了近年来国内外柑橘生物技术的研究进展,主要涉及到以下4个方面:(1)组织培养(包括胚培养、胚珠培养、胚乳培养、花药培养和营养器官培养)与快繁、脱毒和种质资源保存;(2)原生质体培养、再生和融合及体细胞杂种在柑橘砧木及接穗品种改良中的应用;(3)分子标记技术在柑橘遗传多样性检测、基因定位、亲缘关系分析及体细胞杂种鉴定等方面的应用;(4)转基因技术。目前,现代生物技术是柑橘传统育种的有效补充,已成为柑橘遗传改良、种质资源创新和科学研究的重要技术。     

香蕉生物技术研究进展

近50年来香蕉的生产得到了稳步的发展,同时正遭受越来越严重的病虫、霜冻和台风的侵害。鲜食蕉雌雄性高度不育的特性,使得传统的育种方法难以进行香蕉的遗传改良。这些现状迫切要求香蕉生物技术的不断发展和深入。近10年来,在香蕉体细胞胚胎发生、原生质体培养、基因克隆和序列分析以及基因转化等方面都取得了可喜的成果,并预计于2006年完成香蕉基因组的测序 。     

甘薯叶柄原生质体有效植株再生

将甘薯（Ｉｐｏｍｏｅａｂａｔａｔａｓ（Ｌ．）Ｌａｍ．）‘元气’和‘白星’（‘ＷｈｉｔｅＳｔａｒ’）的叶柄原生质体培养在含有０．０５ｍｇ·Ｌ－１２,４Ｄ和０．５ｍｇ·Ｌ－１ＫＴ的改良ＭＳ液体培养基中,３～４ｄ后细胞开始分裂。培养８～９周后,将直径达１～２ｍｍ的愈伤组织转移到添加０．０５～０．２ｍｇ·Ｌ－１２,４Ｄ和０～０．５ｍｇ·Ｌ－１ＫＴ或添加０．５～２．０ｍｇ·Ｌ－１ＮＡＡ和１．０～３．０ｍｇ·Ｌ－１ＢＡＰ的ＭＳ固体增殖培养基上使其增殖。转移３～５周后,将愈伤组织再转移到ＭＳ基本培养基或转移到添加２．０～３．０ｍｇ·Ｌ－１ＢＡＰ的ＭＳ培养基上。当进一步转移到ＭＳ基本培养基上后,从愈伤组织或从愈伤组织形成的不定根上再生出植株。‘元气’植株再生率高达６０．０％,ＷｈｉｔｅＳｔａｒ高达４３．４％。     

Plant regeneration via somatic embryogenesis, and transient gene expression in sweet potato protoplasts

A method for regenerating plants from petiole protoplasts of the in vitro-raised sweet potato cultivar Jewel is described. Protoplast yields of 3.0–5.0×10⁶ were obtained following 4–6 h digestion of 1- to 2-cm petioles (1 g fresh weight) with 1% Cellulase-R10, 2% Macerozyme-R10, and 0.3% Pectolyase Y-23 in a washing solution with 9% mannitol. A plating density of 10⁵ protoplasts/ml was optimal for subsequent division. An initial division frequency of 12–15% was obtained in liquid or agarose-solidified KP8 culture medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) (0.9 μm), and zeatin (2.3 μm). Colonies consisting of 100–200 cells were formed after 4 weeks in the dark at 24±2°C. The frequency of colony formation was improved by the gradual addition of fresh liquid KP8 medium of lower osmoticum. Protocalli (1–2 mm in diameter) were formed after an additional 4–6 weeks under continuous illumination and regular dilution with fresh culture medium. Morphogenic callus formed globular and heart-shaped embryos that developed into cotyledon stage embryos, following transfer of calli onto medium containing 2,4-D (11.3 μm) and benzylaminopurine (2.2 μm). Subsequently, embryo conversion to plantlets was obtained on basal medium with 2% sucrose and 3.5 μm gibberellic acid. Regenerated plantlets were successfully transplanted in soil. Mature plants appeared phenotypically normal. The same petiole protoplast populations showed transient expression of the gusA gene introduced using electroporation. Received: 10 October 1997 / Revision received: 10 February 1998 / Accepted: 2 March 1998     

Optimisation of somatic embryogenesis in fourteen cultivars of sweet potato [Ipomoea batatas (L.) Lam.]

Culture procedures have been developed to facilitate the induction and maintenance of somatic embryogenic tissues in 14 out of 16 tested cultivars of sweet potato [Ipomoea batatas (L.) Lam]. Both the size of the axillary bud explant and the type of auxin were found to be critical for the successful induction of somatic embryogenesis. Of the five auxins screened 2,4-dichlorophenoxyacetic acid 2,4-D and 2,4,5-trichlorophenoxyacetic acid were the most effective, with use of the latter inducing the production of embryogenic tissues in 7 cultivars which responded poorly or not at all to 2,4-D. Procedures for secondary/cyclic embryogenesis, formation of mature embryos and their conversion to plants are also described. Received: 24 September 1996 / Revision received: 16 December 1996 / Accepted 27 January 1997     

湖南甘薯种质资源曲叶病毒检测分析初报

本研究依托"第三次全国农作物种质资源普查与收集行动",利用巢式PCR(Nested PCR)检测技术,对从湖南各地区采集的甘薯种质资源进行甘薯曲叶病毒的调查、检测、统计与分析,获得该地区甘薯种质资源曲叶病毒的感染和分布情况。对收集的246份甘薯种质资源进行了甘薯曲叶病毒病症状的调查,记录了每份种质资源的田间生长特性;建立了一种甘薯曲叶病毒巢式PCR检测技术,该技术相对其他技术具有特异性强、灵敏度高、检测通量大、检测成本低的特点。利用建立的巢式PCR检测技术对选取的样品进行甘薯曲叶病毒检测,分析检测结果发现:(1)巢氏PCR共检测出14份甘薯种质资源感染甘薯曲叶病毒,根据病毒基因测序结果分析湖南省至少存在2种曲叶病毒株系。(2)田间调查共发现8份甘薯种质资源的叶片具有甘薯曲叶病毒病典型的卷曲症状,但是其中仅有4份资源与曲叶病毒巢氏PCR检测结果一致;另外4份资源虽然具有明显的卷叶现象但是未检测出曲叶病毒。(3)曲叶病毒检测呈阳性的14份甘薯种质资源分别来源于邵阳市、长沙市、永州市和株洲市4个地区,占种质资源总数的5.7%;4个地区甘薯种质资源的病毒感染率分别为17.6%、14.5%、7.1%和6.7%;全省范围内的种质资源染病情况具有较大的地域差异性;综合甘薯种植情况和地理环境分析,商品薯的跨区域流通和农民自留种的种植习惯是影响甘薯病毒传播的主要因素。本研究首次利用巢式PCR技术对湖南地区甘薯曲叶病毒进行检测和调查,为甘薯种质资源的保存、繁殖、鉴定与利用提供了重要的技术支撑,也为湖南地区甘薯曲叶病毒侵染情况及相关的分子生物学研究提供了数据参考。     

Cryopreservation of embryogenic tissue of a range of genotypes of sweet potato (Ipomoea batatas [L] Lam.) using an encapsulation protocol

Embryogenic tissue of nine sweet potato [Ipomoea batatas (L.) Lam] genotypes from Asia, Africa and the Americas was established from in vitro axillary buds on Murashige and Skoog medium supplemented with 2,4-dichlorophenoxyacetic acid or 2,4,5-trichlorophenoxyacetic acid. Embryogenic aggregates, 1.0–2.0 mm in diameter, were encapsulated in alginate gel, precultured on medium containing elevated levels of sucrose and dehydrated prior to rapid freezing in liquid nitrogen. The maximum survival of embryogenic tissue ranged from 4% to 38%, depending on the genotype. With the incorporation of a slow-cooling step, survival was generally much higher than that obtained after rapid freezing alone. Five of eight genotypes tested with this protocol gave survival percentages in excess of 55%, and a further two in excess of 33%, all after evaporative dehydration. The most effective sucrose treatment(s), however, varied with the genotype. Received: 7 October 1996 / Revision received: 16 December 1996 / Accepted 27 January 1997